WO2025059489A1

WO2025059489A1 - Sequential dual alignment of two-dimensional (2d) platelets in composite matrix structure printing and nanoparticle modified 2d platelets therefor

Info

Publication number: WO2025059489A1
Application number: PCT/US2024/046657
Authority: WO
Inventors: Yong Huang; Yunxia CHEN
Original assignee: University of Florida; University of Florida Research Foundation Inc
Current assignee: University of Florida; University of Florida Research Foundation Inc
Priority date: 2023-09-15
Filing date: 2024-09-13
Publication date: 2025-03-20
Anticipated expiration: 2026-03-15

Abstract

Systems, apparatuses, methods, and computer program products are described herein for yield-stress support bath sequential dual-alignment of two-dimensional (2D) platelets in a curable liquid matrix of a build material being supported within the yield-stress support bath. An initial alignment of the 2D platelets in the build material can be achieved by choosing a particular dispensing nozzle that exerts suitable shear forces on the build material, causing the 2D platelets to at least partially align. Printing the build material in the yield-stress support bath forms an intermediate article. An external field, such as a magnetic field, can be exerted by a field generator on the intermediate article, causing a subsequent alignment of the 2D platelets. The yield-stress support bath and/or the field generator can be rotated relative to each other such that any alignment direction can be achieved for the subsequent alignment relative to the initial alignment of the 2D platelets.

Description

SEQUENTIAL DUAL ALIGNMENT OF TWO-DIMENSIONAL (2D) PLATELETS IN

COMPOSITE MATRIX STRUCTURE PRINTING AND NANOPARTICLE MODIFIED

2D PLATELETS THEREFOR

Cross-Reference to Related Applications

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63/538,608, filed September 15, 2023 and entitled “Sequential Dual Alignment of Two-Dimensional (2D) Platelets in Composite Matrix Structure Printing and Nanoparticle Modified 2D Platelets Therefor,” the entire disclosure of which is hereby incorporated herein by reference in its entirety for all purposes.

Statement of Government Support

[0002] This invention was made with government support under Grant No. DE- SC0023389, awarded by the US Department of Energy, and Grant No. 1762941, awarded by the National Science Foundation. The government has certain rights in the invention.

Field

[0003] This disclosure relates to printing inks for formation of articles and structures into a yield-stress support material, alignment of two-dimensional (2D) platelets in the printing ink, and modification of 2D platelets for alignment thereof using an external field.

Background

[0004] Additive manufacturing, also commonly known as three-dimensional (3D) printing, encompasses a range of technologies used to fabricate parts by adding material to build up the part rather than by subtracting unwanted material away from a bulk starting workpiece. For freeform 3D printing of functional structures, liquid extrusion, sometimes know n as direct ink writing, can be used due to its ease of implementation, high efficiency, and wide range of printable materials. However, conventional direct ink writing methods are typically not appropriate for aligning two-dimensional (2D) plate-like materials within the build material during printing articles. Summary

[0005] Described herein are systems, apparatuses, methods, and computer program products are described herein for yield-stress support bath sequential dual-alignment of two- dimensional (2D) platelets in a curable liquid matrix of a build material being supported within the yield-stress support bath. An initial alignment of the 2D platelets in the build material can be achieved by choosing a particular dispensing nozzle that exerts suitable shear forces on the build material, causing the 2D platelets to at least partially align. Printing the build material in the yield-stress support bath forms an intermediate article. An external field, such as a magnetic field, can be exerted by a field generator on the intermediate article, causing a subsequent alignment of the 2D platelets. The yield-stress support bath and/or the field generator can be rotated relative to each other such that any alignment direction can be achieved for the subsequent alignment relative to the initial alignment of the 2D platelets.

[0006] Aspects of the present disclosure are directed to sequential dual alignments that introduce a synergistic effect on hexagonal boron nitride platelets for superior thermal performance, such as described in Chen, Y., Gao, Z., Hoo. S.A., Tipnis, V., Wang, R., Mitevski, I., Hitchcock, D., Simmons, K.L., Sun, Y ., Samtinoranont, M., Huang, Y., “Sequential Dual Alignments Introduce Synergistic Effect on Hexagonal Boron Nitride Platelets for Superior Thermal Performance,” (2024) Advanced Materials, p. 2314097, https://doi.org/10.1002/adma.202314097, the entire disclosure of which is hereby incorporated herein by reference in its entirety for all purposes.

[0007] According to a first aspect, a method can be carried out that comprises: causing a print nozzle to move along a predefined pathway through a yield-stress support material; while causing the print nozzle to move along the predefined pathway through the yield-stress support material, communicating a printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material to form an intermediate structured article; exposing the intermediate structured article in the yield-stress support material to an external field, thereby causing at least partial alignment of the printing material in the intermediate structured article in an alignment direction; and at least partially curing the intermediate structured article in the yield-stress support material to form a finished structured article.

[0008] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, the method can further comprise: rotating the rotatable platform, while exposing the intermediate structured article in the yield-stress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the alignment direction is a second alignment direction, and wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material. In some embodiments, the first alignment direction is different than the second alignment direction. In some embodiments, the yield-stress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0009] In some embodiments, the method can further comprise: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, the method can further comprise: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesO-i) nanoparticles. [0010] According to a second aspect, a method can be carried out that comprises: communicating a printing ink through a printing nozzle and into a yield-stress support material while moving the nozzle along a predefined pathway through the yield-stress support material to form an intermediate structured article, wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material; after communicating the printing ink into the yield-stress support material to form the intermediate structured article, exposing the intermediate structured article in the yield-stress support material to an electromagnetic field or an electrical field, thereby- inducing a second alignment direction to be formed in the intermediate structured article, the second alignment direction being different than the first alignment direction; and exposing the intermediate structured article in the yield-stress support material to heat, a curing agent, or a curing light, thereby at least partially curing the printing ink in the intermediate structured article.

[0011] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, the method can further comprise: rotating the rotatable platform, while exposing the intermediate structured article in the yield-stress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the yield-stress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0012] In some embodiments, the method can further comprise: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, the method can further comprise: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesCh) nanoparticles. [0013] According to a third aspect, a method can be carried out that comprises: causing a print nozzle to move along a predefined pathway through a yield-stress support material; while causing the pnnt nozzle to move along the predefined pathway through the yield-stress support material, communicating a printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material to form an intermediate structured article, wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material; exposing the intermediate structured article in the yield-stress support material to an electromagnetic field or an electrical field, thereby causing at least partial alignment of the printing material in the intermediate structured article in a second alignment direction; and at least partially curing the intermediate structured article in the yield-stress support material to form a finished structured article.

[0014] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, the method can further comprise: rotating the rotatable platform, while exposing the intermediate structured article in the yield-stress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the second alignment direction is different than the first alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the yield-stress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0015] In some embodiments, the method can further comprise: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, the method can further comprise: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesCh) nanoparticles. [0016] According to a fourth aspect, an apparatus can be provided that comprises: at least one processor; and at least one memory' storing instructions thereon that, when executed by the at least one processor, cause the apparatus to perform at least: causing a print nozzle to move along a predefined pathway through a yield-stress support material; while causing the print nozzle to move along the predefined pathway through the yield-stress support material, communicating a printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material to form an intermediate structured article; exposing the intermediate structured article in the yield-stress support material to an external field, thereby causing at least partial alignment of the printing material in the intermediate structured article in an alignment direction; and at least partially curing the intermediate structured article in the yield-stress support material to form a finished structured article.

[0017] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, the instructions stored on the at least one memory, when executed by the at least one processor, further cause the apparatus to perform: rotating the rotatable platform, while exposing the intermediate structured article in the yieldstress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the alignment direction is a second alignment direction, and wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material. In some embodiments, the first alignment direction is different than the second alignment direction. In some embodiments, the yield-stress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0018] In some embodiments, the instructions stored on the at least one memory, when executed by the at least one processor, further cause the apparatus to perform: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, the instructions stored on the at least one memory, when executed by the at least one processor, further cause the apparatus to perform: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesCh) nanoparticles.

[0019] According to a fifth aspect, an apparatus can be provided that comprises: at least one processor; and at least one memory storing instructions thereon that, when executed by the at least one processor, cause the apparatus to perform at least: communicating a printing ink through a printing nozzle and into a yield-stress support material while moving the nozzle along a predefined pathway through the yield-stress support material to form an intermediate structured article, wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material; after communicating the printing ink into the yield-stress support material to form the intermediate structured article, exposing the intermediate structured article in the yield-stress support material to an electromagnetic field or an electrical field, thereby inducing a second alignment direction to be formed in the intermediate structured article, the second alignment direction being different than the first alignment direction; and exposing the intermediate structured article in the yield-stress support material to heat, a curing agent, or a curing light, thereby at least partially curing the printing ink in the intermediate structured article.

[0020] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, the instructions stored on the at least one memory, when executed by the at least one processor, further cause the apparatus to perform: rotating the rotatable platform, while exposing the intermediate structured article in the yieldstress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the yield-stress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0021] In some embodiments, the instructions stored on the at least one memory, when executed by the at least one processor, further cause the apparatus to perform: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, the instructions stored on the at least one memory, when executed by the at least one processor, further cause the apparatus to perform: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesO-i) nanoparticles.

[0022] According to a sixth aspect, an apparatus can be provided that comprises: at least one processor; and at least one memory⁷ storing instructions thereon that, when executed by the at least one processor, cause the apparatus to perform at least: causing a print nozzle to move along a predefined pathway through a yield-stress support material; while causing the print nozzle to move along the predefined pathway through the yield-stress support material, communicating a printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material to form an intermediate structured article, wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material; exposing the intermediate structured article in the yield-stress support material to an electromagnetic field or an electrical field, thereby causing at least partial alignment of the printing material in the intermediate structured article in a second alignment direction; and at least partially curing the intermediate structured article in the yield-stress support material to form a finished structured article.

[0023] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, the instructions stored on the at least one memory, when executed by the at least one processor, further cause the apparatus to perform: rotating the rotatable platform, while exposing the intermediate structured article in the yieldstress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the second alignment direction is different than the first alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the yield-stress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0024] In some embodiments, the instructions stored on the at least one memory, when executed by the at least one processor, further cause the apparatus to perform: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, the instructions stored on the at least one memory, when executed by⁷ the at least one processor, further cause the apparatus to perform: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesCfi) nanoparticles.

[0025] According to a seventh aspect, a computer program product, such as a non- transitory computer readable storage medium can be provided that comprises instructions stored thereon that, when executed by a processor, cause a machine to perform at least: causing a print nozzle to move along a predefined pathway through a yield-stress support material; while causing the print nozzle to move along the predefined pathway through the yield-stress support material, communicating a printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material to form an intermediate structured article; exposing the intermediate structured article in the yieldstress support material to an external field, thereby causing at least partial alignment of the printing material in the intermediate structured article in an alignment direction; and at least partially curing the intermediate structured article in the yield-stress support material to form a finished structured article.

[0026] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: rotating the rotatable platform, while exposing the intermediate structured article in the yield-stress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the alignment direction is a second alignment direction, and wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material. In some embodiments, the first alignment direction is different than the second alignment direction. In some embodiments, the yieldstress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0027] In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesC ) nanoparticles.

[0028] According to an eighth aspect, a computer program product, such as a non- transitory computer readable storage medium can be provided that comprises instructions stored thereon that, when executed by a processor, cause a machine to perform at least: communicating a printing ink through a printing nozzle and into a yield-stress support material while moving the nozzle along a predefined pathway through the yield-stress support material to form an intermediate structured article, wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material; after communicating the printing ink into the yield-stress support material to form the intermediate structured article, exposing the intermediate structured article in the yield-stress support material to an electromagnetic field or an electrical field, thereby inducing a second alignment direction to be formed in the intermediate structured article, the second alignment direction being different than the first alignment direction; and exposing the intermediate structured article in the yield-stress support material to heat, a curing agent, or a curing light, thereby at least partially curing the printing ink in the intermediate structured article.

[0029] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: rotating the rotatable platform, while exposing the intermediate structured article in the yield-stress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the yield-stress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0030] In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesCfi) nanoparticles.

[0031] According to a ninth aspect, a computer program product, such as a non-transitory computer readable storage medium can be provided that comprises instructions stored thereon that, when executed by a processor, cause a machine to perform at least: causing a print nozzle to move along a predefined pathway through a yield-stress support material; while causing the print nozzle to move along the predefined pathway through the yield-stress support material, communicating a printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material to form an intermediate structured article, wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material; exposing the intermediate structured article in the yield-stress support material to an electromagnetic field or an electrical field, thereby causing at least partial alignment of the printing material in the intermediate structured article in a second alignment direction; and at least partially curing the intermediate structured article in the yield-stress support material to form a finished structured article.

[0032] In some embodiments, the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field. In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: rotating the rotatable platform, while exposing the intermediate structured article in the yield-stress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction. In some embodiments, the second alignment direction is different than the first alignment direction. In some embodiments, the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article. In some embodiments, the yield-stress support material comprises a Carbopol microgel. In some embodiments, the printing ink comprises at least one of: a cross-linkable material, a curable material, a monomeric material, a prepolymer, an epoxy, or a resin. In some embodiments, the external field comprises one or more of: an electromagnetic field, a magnetic field, an electrical field, radiation, a gravitational field, radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, or gamma rays.

[0033] In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink. In some embodiments, the 2D platelets comprise at least one of: hexagonal boron nitride (hBN), modified hBN, graphene, reduced graphene oxide flakes, or transition metal dichalcogenides comprising a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. In some embodiments, when executed by the processor, the instructions stored on the non-transitory computer readable storage medium further cause the machine to perform at least: at least partially coating the 2D platelets with smaller particles that are responsive to the external field before communicating the 2D platelets into the curable liquid matrix. In some embodiments, the smaller particles comprise iron oxide (FesC nanoparticles.

Brief Description of the Drawings

[0034] Having thus described the invention in general terms, reference will now be made to the accompanying drawings. The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e g., functionally similar and/or structurally similar elements).

[0035] FIG. 1 provides a block flow diagram of an example system for carrying out yieldstress support bath-enabled sequential dual-alignment of 2D platelets in build material during three-dimensional (3D) printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure.

[0036] FIGs. 2A-2I provide schematics of a 3D printing assembly for carrying out yieldstress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to embodiments of the present disclosure. FIG. 2A illustrates a process for yield-stress support bath-enabled sequential dualalignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure. FIG. 2B illustrates a portion of a process for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure. FIG. 2C illustrates a portion of a process for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure. FIG. 2D illustrates a portion of a process for yield-stress support bath- enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure. FIG. 2E illustrates a portion of a process for yield-stress support bath-enabled sequential dualalignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure. FIG. 2F illustrates a portion of a process for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure. FIG. 2G illustrates a portion of a process for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure. FIG. 2H illustrates a portion of a process for yield-stress support bath- enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure. FIG. 21 illustrates a portion of a process for yield-stress support bath-enabled sequential dualalignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure.

[0037] FIG. 3 provides a block flow diagram of an example process for carrying out yieldstress support bath-enabled sequential dual-alignment of 2D platelets in build material during three-dimensional (3D) printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure.

[0038] FIGs. 4A-4D provide schematics of a 3D printing assembly for carrying out yieldstress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to embodiments of the present disclosure. FIG. 4A illustrates the 3D printing assembly throughout a process for carrying out yield-stress support bath-enabled sequential dual -alignment of 2D platelets in build material during 3D printing of an article in the yield-stress support bath, according to an embodiment of the present disclosure. FIG. 4B illustrates the 3D printing assembly during a portion of the process for carrying out yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in the yield-stress support bath, according to an embodiment of the present disclosure. FIG. 4C illustrates the 3D printing assembly during a portion of the process for carry ing out yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in the yield-stress support bath, according to an embodiment of the present disclosure. FIG. 4D illustrates the 3D printing assembly during a portion of the process for carrying out yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during 3D printing of an article in the yield-stress support bath, according to an embodiment of the present disclosure. [0039] FIGs. 5A-5E provide schematics of a 3D printing assembly and process for carrying out yield-stress support bath-enabled sequential dual -alignment of 2D platelets in build material during 3D printing of an article in a yield-stress support bath, according to embodiments of the present disclosure. FIG. 5A illustrates the 3D printing assembly comprising the yield-stress support bath and being configured to apply a rotating magnetic field before, during, and/or after printing of a composite ink into the yield-stress support bath, according to embodiments of the present disclosure. FIG. 5B illustrates the process for initially printing a composite ink into a yield-stress support bath of the 3D printing assembly of FIG. 5A. FIG. 5C illustrates a first portion of the process of FIG. 5B in which the composite ink is being printed into the yield-stress support bath, according to embodiments of the present disclosure. FIG. 5D illustrates a second portion of the process of FIG. 5B, according to embodiments of the present disclosure. FIG. 5E illustrates the printing direction relative to the rotating magnetic field direction during the process of FIG. 5B, according to embodiments of the present disclosure.

[0040] FIG. 6 illustrates a measurement setup for measuring heat dissipation from a heat sink, according to embodiments of the present disclosure. The top inset illustrates heat flow along the fins of the heat sink. The bottom inset is a photograph of a 3D printed heat sink for which the measurement setup can be used to measure heat dissipation therefrom, according to an embodiment of the present disclosure.

[0041] FIG. 7 provides an array of infrared (IR) images of heat dissipation performance for a variety of different 3D printed heat sinks, including a control heat sink and heat sinks printed from 40 wt.% mhBN composite ink, and either exposed to no alignment force, a single alignment force, or dual -alignment forces, as a function of heat sink performance measurement time (duration of heat sink exposure before IR image was taken) for heat sinks printed into a yield-stress support bath material, according to embodiments of the present disclosure.

[0042] FIG. 8 is a graph of temperature profile at a top surface of the heat sink fins of the heat sinks in FIG. 7 during heating, according to some embodiments of the present disclosure. The error ranges around each line represent ± one sigma (o), or one standard deviation.

[0043] FIG. 9 is a graph of temperature profile at a top surface of the heat sink fins of the heat sinks in FIG. 7 during cooling, according to some embodiments of the present disclosure. The error ranges around each line represent ± one sigma (o), or one standard deviation. [0044] FIG. 10 provides a schematic of an example computing device configured to 3D print according to any of the approaches or methods of the present disclosure.

[0045] FIG. 11 provides a schematic of an example external computing device configured to 3D print according to any of the approaches or methods of the present disclosure.

[0046] FIG. 12 illustrates a process flow diagram of a method for carrying out yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during three- dimensional (3D) printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure.

[0047] FIG. 13 illustrates a process flow diagram of a method for carry ing out yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during three- dimensional (3D) printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure.

[0048] FIG. 14 illustrates a process flow diagram of a method for carrying out yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during three- dimensional (3D) printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure.

[0049] FIG. 15 illustrates a process flow diagram of a method for carrying out yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during three- dimensional (3D) printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure.

[0050] FIG. 16 illustrates a process flow diagram of a method for carrying out yield-stress support bath-enabled sequential dual-alignment of 2D platelets in build material during three- dimensional (3D) printing of an article in a yield-stress support bath, according to an embodiment of the present disclosure.

[0051] FIG. 17 is a scanning electron microscope (SEM) image of amhBN control sample, according to an embodiment of the present disclosure. The scale bar illustrates 2 pm.

[0052] FIG. 18 is an SEM image of cross-sectional morphology of mhBN aligned in a sample printed with relatively small extrusion-induced shear force conditions, according to an embodiment of the present disclosure. The inset schematic illustrates the mhBN orientation state. The scale bar illustrates 2 pm.

[0053] FIG. 19 is an SEM image of cross-sectional morphology of mhBN aligned in a sample printed with relatively large extrusion-induced shear force conditions, according to an embodiment of the present disclosure. The inset schematic illustrates the mhBN orientation state. The scale bar illustrates 2 pm.

[0054] FIG. 20 is a graph illustrating thermal conductivity versus shear force conditions, with * representing a p < 0.05, ** representing a p < 0.01, and *** representing a p < 0.001, according to some embodiments of the present disclosure. For all sample groups, n=5.

[0055] FIG. 21 is an SEM image of cross-sectional morphology of mhBN aligned in a cast sample printed with a static magnetic field applied, according to an embodiment of the present disclosure. The inset schematic illustrates the mhBN orientation state. The scale bar illustrates 2 pm.

[0056] FIG. 22 is an SEM image of cross-sectional morphology of mhBN aligned in a cast sample with a rotating magnetic field applied, according to an embodiment of the present disclosure. The inset schematic illustrates the mhBN orientation state. The scale bar illustrates 2 pm.

[0057] FIG. 23 is a graph illustrating respective thermal performance relative to magnetic field applied for the samples illustrated in FIGs. 19 and 20. with * representing ap < 0.05, ** representing ap < 0.01, and *** representing a p < 0.001, according to embodiments of the present disclosure. For all sample groups, n=5.

[0058] FIG. 24 is an SEM image of cross-sectional morphology of mhBN aligned in a sample printed with relatively small extrusion-induced shear force conditions and with a rotating magnetic field applied, according to an embodiment of the present disclosure. The inset schematic illustrates the mhBN orientation state. The scale bar illustrates 2 pm.

[0059] FIG. 25 is an SEM image of cross-sectional morphology of mhBN aligned in a sample printed with relatively large extrusion-induced shear force conditions and with a rotating magnetic field applied, according to an embodiment of the present disclosure. The inset schematic illustrates the mhBN orientation state. The scale bar illustrates 2 pm.

[0060] FIG. 26 is a graph illustrating the results of x-ray diffraction (XRD) analysis of 20 wt.% mhBN/epoxy composite samples under different observation directions, including dually-aligned samples observed parallelly and perpendicularly to the printing direction, according to some embodiments of the present disclosure. For all sample groups, n=5.

[0061] FIG. 27 is a graph illustrating the thermal conductivity of samples prepared under different alignment methods and improved due to synergistic effects of shear force conditions and magnetic field conditions during printing, with * representing ap < 0.05, ** representing a p < 0.01, and *** representing ap < 0.001, according to some embodiments of the present disclosure. For all sample groups, n=5.

[0062] FIG. 28 is a graph illustrating the thermal performance of samples prepared from different composite ink compositions as a factor of mhBN concentration, according to some embodiments of the present disclosure. For all sample groups, n=5.

[0063] FIG. 29 is a graph comparing thermal conductivity of hBN/epoxy composites under the dual-alignment approach with results achieved according to different approaches and systems. The error bars represent ± one sigma (o), or one standard deviation.

[0064] FIG. 30 is a graph comparing shear rate versus viscosity of various inks with different mhBN concentrations as well as linear regression models of the same, according to some embodiments of the present disclosure. The error bars represent ± one sigma (o), or one standard deviation.

[0065] FIG. 31 is a graph comparing flow consistency index (K) and power-law index (n) for various inks with different mhBN concentrations, according to some embodiments of the present disclosure.

[0066] FIG. 32 is a graph comparing maximum shear stress when using different dispensing nozzles having different sizes (gauges), according to some embodiments of the present disclosure.

[0067] FIG. 33 is a schematic diagram of a force analysis of a single mhBN platelet in an external magnetic field, according to some embodiments of the present disclosure.

[0068] FIG. 34 is a graph comparing magnetic torque versus viscous torques as a function of mhBN platelet orientation, according to some embodiments of the present disclosure.

[0069] FIG. 35 is a graph of net torque as a function of mhBN platelet orientation, according to some embodiments of the present disclosure.

[0070] FIG. 36 is a graph of composite ink viscosity as a function of mhBN/epoxy composite ink post-mixing time at which the viscosity⁷ was measured, according to some embodiments of the present disclosure. The error bars represent ± one sigma (o), or one standard deviation.

[0071] FIG. 37 is agraph of time needed or alignment of platelets within the ink for various inks with different mhBN concentrations as a function of ink post-mixing times when alignment is carried out, according to some embodiments of the present disclosure.

[0072] FIG. 38Ais an image of a mhBN dispersion in deionized (DI) water. [0073] FIG. 38B is an image of mhBN in DI water that has settled to the bottom of a beaker in an absence of an externally applied magnetic field and a bubble foam floating at a top of the beaker that formed due to continuous shaking during the process of preparing the mhBN/DI water mixture.

[0074] FIG. 38C is an image of mhBN response to an externally applied magnetic field placed nearby the beaker resulting in at least partial redispersion of the mhBN within the DI water and a bubble foam floating at a top of the beaker that formed due to continuous shaking during the process of preparing the mhBN/DI water mixture.

[0075] FIG. 39 is a bright-field transmission electron microscopy (TEM) image of FestTi nanoparticles on the surface of a hBN platelet, according to an embodiment of the present disclosure.

[0076] FIG. 40 is an image generated using energy dispersive X-ray spectroscopy in scanning transmission electron microscopy (STEM-EDS) of a selected area on the surface of an mhBN platelet, according to an embodiment of the present disclosure.

[0077] FIG. 41 is a STEM-EDS image of the selected area on the surface of the mhBN platelet from FIG. 40 indicating the presence of iron within the selected area on the surface of the mhBN platelet, according to an embodiment of the present disclosure.

[0078] FIG. 42 is a STEM-EDS image of the selected area on the surface of the mhBN platelet from FIG. 40 indicating the presence of oxygen within the selected area on the surface of the mhBN platelet, according to an embodiment of the present disclosure.

[0079] FIG. 43 is a STEM-EDS image of the selected area on the surface of the mhBN platelet from FIG. 40 indicating the presence of boron within the selected area on the surface of the mhBN platelet, according to an embodiment of the present disclosure.

[0080] FIG. 44 is a STEM-EDS image of the selected area on the surface of the mhBN platelet from FIG. 40 indicating the presence of nitrogen or nitrogen-comprising materials within the selected area on the surface of the mhBN platelet, according to an embodiment of the present disclosure.

[0081] FIG. 45 is an image of a selected area on the surface of a sample of mhBN/epoxy composite ink selected for EDS analysis and element mapping taken from a top-down perspective of the surface rather than a cross-sectional perspective, according to an embodiment of the present disclosure. [0082] FIG. 46 is a carbon (C) EDS element map of the selected area on the surface of the mhBN/epoxy composite ink sample in FIG. 45 and showing that mhBN platelets coated with Fe^Ch nanoparticles are homogenously dispersed in the epoxy matrix, according to an embodiment of the present disclosure. The scale bar represents 10 pm.

[0083] FIG. 47 is a boron (B) EDS element map of the selected area on the surface of the mhBN/epoxy composite ink sample in FIG. 45 and showing that mhBN platelets coated with FesOr nanoparticles are homogenously dispersed in the epoxy matrix, according to an embodiment of the present disclosure. The scale bar represents 10 pm.

[0084] FIG. 48 is a nitrogen (N) EDS element map of the selected area on the surface of the mhBN/epoxy composite ink sample in FIG. 45 and showing that mhBN platelets coated with FesO4 nanoparticles are homogenously dispersed in the epoxy matrix, according to an embodiment of the present disclosure. The scale bar represents 10 pm.

[0085] FIG. 49 is an iron (Fe) EDS element map of the selected area on the surface of the mhBN/epoxy composite ink sample in FIG. 45 and showing that mhBN platelets coated with FesO-i nanoparticles are homogenously dispersed in the epoxy matrix, according to an embodiment of the present disclosure. The scale bar represents 10 pm.

[0086] FIG. 50 is an oxygen (O) EDS element map of the selected area on the surface of the mhBN/epoxy composite ink sample in FIG. 45 and showing that mhBN platelets coated with FesO4 nanoparticles are homogenously dispersed in the epoxy matrix, according to an embodiment of the present disclosure. The scale bar represents 10 pm.

[0087] FIG. 51 A is a perspective image of a printing setup, according to an embodiment of the present disclosure.

[0088] FIG. 5 IB is a perspective image of a dual -alignment setup within the printing setup of FIG. 51 A. according to an embodiment of the present disclosure.

[0089] FIG. 52 is a graph illustrating a maximum shear stress measured for several different dispensing nozzles having different sizes, according to an embodiment of the present disclosure.

[0090] FIG. 53 is an image of a filament encased with an epoxy shell possibly formed due to wall friction during printing with a nozzle having a diameter of 580 pm, according to an embodiment of the present disclosure. The dashed rectangle emphasizes the epoxy shell. [0091] FIG. 54 is an image of a filament encased with an epoxy shell possibly formed due to wall friction during printing with a nozzle having a diameter of 279 pm, according to an embodiment of the present disclosure. The dashed rectangle emphasizes the epoxy shell.

[0092] FIG. 55 is a graph comparing shell thickness about a filament and shell thickness ratio to nozzle diameter, according to embodiments of the present disclosure.

[0093] FIG. 56 is a graph comparing thermal conductivity values under different alignment approaches, according to embodiments of the present disclosure.

[0094] FIG. 57 is a graph of XRD measurement data to evaluate the degree of composite heterogeneity as a function of alignment methods for magnetic field intensity.

[0095] FIG. 58 is a graph of XRD measurement data to evaluate the degree of composite heterogeneity as a function of alignment methods for relative intensity (I100/I002))) and mhBN concentration. The error bars represent ± one sigma (o), or one standard deviation.

[0096] FIG. 59 is a graph of XRD measurement data to evaluate the degree of composite heterogeneity as a function of alignment methods for intensity.

[0097] FIG. 60 is a graph of XRD measurement data to evaluate the degree of composite heterogeneity as a function of alignment methods for relative intensity. The error bars represent ± one sigma (o), or one standard deviation.

[0098] FIG. 61 is a graph comparing a pure thermal enhancement factor (TEF_P) of an mhBN/epoxy composite printed using a dual -alignment approach, according to an embodiment of the present disclosure, to the TEF_P of existing composites. The error bars represent ± one sigma (o), or one standard deviation.

[0099] FIG. 62 is a graph comparing a relative TEF (TEFr) of mhBN/epoxy composite printed using a dual-alignment approach, according to an embodiment of the present disclosure, to the TEFr of existing composites. The error bars represent ± one sigma (o), or one standard deviation. TEFr is defined as the relative thermal enhancement factor as calculated by benchmarking against non-aligned counterparts with the same hBN concentration as the baseline.

[0100] FIG. 63 is a graph of thermal conductivity measured along a through-plane direction through 20 wt.% mhBN/epoxy composite samples fabricated using different alignment approaches, according to embodiments of the present disclosure. The error bars represent ± one sigma (o), or one standard deviation. [0101] FIG. 64 illustrates a measurement direction for measuring dielectric properties of a 40 wt.% mhBN/epoxy composite sample fabricated with no alignment of platelets, according to an embodiment of the present disclosure.

[0102] FIG. 65 illustrates a measurement direction for measuring dielectric properties of a 40 wt.% mhBN/epoxy composite sample fabricated with single alignment of platelets, according to an embodiment of the present disclosure.

[0103] FIG. 66 illustrates a measurement direction for measuring dielectric properties of a 40 wt.% mhBN/epoxy composite sample fabricated with dual alignment of platelets, according to an embodiment of the present disclosure.

[0104] FIG. 67 is a graph of dielectric constant for mhBN/epoxy composite samples fabricated and measured as illustrated in FIGs. 64, 65, and 66. according to embodiments of the present disclosure. The error bars represent ± one sigma (o), or one standard deviation.

[0105] FIG. 68 is a graph of dissipation factor as a function of frequency for mhBN/epoxy composite samples fabricated and measured as illustrated in FIGs. 64. 65, and 66. according to embodiments of the present disclosure. The error bars represent ± one sigma (o), or one standard deviation.

[0106] FIG. 69 is a graph comparing magnetic and viscous torque responses to ink viscosity for samples having platelets aligned according to a range of different platelet orientations, according to embodiments of the present disclosure.

[0107] FIG. 70 is a graph comparing magnetic and viscous torque responses to magnetic field strength for samples having platelets aligned according to a range of different platelet orientations, according to embodiments of the present disclosure.

[0108] FIG. 71 is a graph comparing net torque responses to ink viscosity for samples having platelets aligned according to a range of different platelet orientations, according to embodiments of the present disclosure.

[0109] FIG. 72 is a graph comparing net torque responses to magnetic field strength for samples having platelets aligned according to a range of different platelet orientations, according to embodiments of the present disclosure.

[0110] FIG. 73 is a graph of thermal conductivity values for epoxy and epoxy composites having an hBN concentration of 30 wt.%, according to an embodiment of the present disclosure. The error bars represent ± one sigma (o), or one standard deviation. Detailed Description

[0111] The present disclosure more fully describes various embodiments with reference to the accompanying drawings. It should be understood that some, but not all embodiments are shown and described herein. Indeed, the embodiments may take many different forms, and accordingly this disclosure should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0112] Various embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. The term “or” is used herein in both the alternative and conjunctive sense, unless otherwise indicated. The terms “illustrative” and “exemplary ” are used to be examples with no indication of quality level. Like numbers refer to like elements throughout.

[0113] As used herein, the terms “instructions,” “file,” “designs,” “data,” “content,” “information,” and similar terms may be used interchangeably, according to some example embodiments of the present invention, to refer to data capable of being transmitted, received, operated on, displayed, and/or stored. Thus, use of any such terms should not be taken to limit the spirit and scope of the disclosure. Further, where a computing device is described herein to receive data from another computing device, it w ill be appreciated that the data may be received directly from the other computing device or may be received indirectly via one or more computing devices, such as, for example, one or more servers, relays, routers, network access points, base stations, and/or the like.

[0114] As used herein, the term “computer-readable medium” refers to any medium configured to participate in providing information to a processor, including instructions for execution. Such a medium may take many forms, including, but not limited to a non-transitoiy computer-readable storage medium (for example, non-volatile media, volatile media), and transmission media. Transmission media include, for example, coaxial cables, copper wire, fiber optic cables, and carrier waves that travel through space without wires or cables, such as acoustic waves and electromagnetic waves, including radio, optical, and infrared waves. Signals include man-made transient variations in amplitude, frequency, phase, polarization, or other physical properties transmitted through the transmission media. Examples of non- transitory computer-readable media include a floppy disk, a flexible disk, hard disk, magnetic tape, any other non-transitory magnetic medium, a compact disc read only memory (CD- ROM), compact disc compact disc-rewritable (CD-RW), digital versatile disc (DVD), Blu- Ray, any other non-transitory optical medium, punch cards, paper tape, optical mark sheets, any other physical medium with patterns of holes or other optically recognizable indicia, a random access memory (RAM), a programmable read only memory (PROM), an erasable programmable read only memory (EPROM), a FLASH-EPROM, any other memory chip or cartridge, a carrier wave, or any other non-transitor ' medium from which a computer can read. The term computer-readable storage medium is used herein to refer to any computer-readable medium except transmission media. However, it will be appreciated that where embodiments are described to use a computer-readable storage medium, other types of computer-readable mediums may be substituted for or used in addition to the computer-readable storage medium in alternative embodiments. By way of example only, a design file for a printed article may be stored on a computer-readable medium and may be read by a computing device, such as described hereinbelow, for controlling part or all of a three-dimensional (3D) printing process and associated apparatuses and components, according to various embodiments described herein.

[0115] As used herein, the term "‘circuitry” refers to all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry); (b) to combinations of circuits and computer program product(s) comprising software (and/or firmware instructions stored on one or more computer readable memories), such as (as applicable): (i) to a combination of processor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)). software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions described herein); and (c) to circuits, such as, for example, a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of “circuitry” applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term “circuitry” would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term “circuitry ” would also cover, for example and if applicable to the particular claim element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, other network device, and/or other computing device.

[0116] As used herein, the term “computing device” refers to a specialized, centralized device, network, or system, comprising at least a processor and a memory device including computer program code, and configured to provide guidance or direction related to the charge transactions carried out in one or more charging networks.

[0117] As used herein, the terms “about,” “substantially,” and “approximately” generally mean plus or minus 10% of the value stated, e.g., about 250 pm would include 225 pm to 275 pm, about 1.000 pm would include 900 pm to 1,100 pm. Any provided value, whether or not it is modified by terms such as “about,” “substantially.” or “approximately,” all refer to and hereby disclose associated values or ranges of values thereabout, as described above.

[0118] Systems, apparatuses, methods, and computer program products are described herein for yield-stress support bath sequential dual-alignment of two-dimensional (2D) platelets in a curable liquid matrix of a build material being supported within the yield-stress support bath. An initial alignment of the 2D platelets in the build material can be achieved by choosing a particular dispensing nozzle that exerts suitable shear forces on the build material, causing the 2D platelets to at least partially align with, e.g, a direction of flow of the build material through the nozzle. Once the build material is dispensed in the yield-stress support bath, an intermediate article is formed. An external field, such as an electromagnetic field, a magnetic field, or electric field, can be exerted by a field generator on the intermediate article, causing a subsequent alignment of the 2D platelets. The yield-stress support bath and/or the field generator can be rotated relative to each other and/or the printing nozzle such that any number of directions can be achieved for the subsequent alignment relative to the initial alignment of the 2D platelets.

[0119] This disclosure presents a sequential dual -alignment approach for the planar alignment of two-dimensional (2D) plate-like materials in desired directions in curable liquid matrix during printing composites or composite structures. The 2D material alignment can be achieved by using nozzle-based printing-induced shear forces for inducing an initial alignment during printing in a yield-stress support bath, followed by an additional torque being exerted on for a subsequent alignment of the 2D material after printing by using external magnetic, electric, and/or other field(s). The external field(s) are chosen to be reactive with the 2D materials being printed. Specifically, the dual-alignment mechanism is enabled by the yieldstress property of the support bath, which makes the external field-based post-printing alignment feasible. The yield-stress support bath can trap the extruded ink in situ and retain the printed shape in a 3D structure even though the ink has a low viscosity. This allows deposited 2D materials in 3D structures to be further aligned under an external field during the printing and post-printing phases. The dual-alignment technology’ enables the effective planar alignment of 2D plate-like materials in desired directions, allowing for the creation of intricate microstructures in printing three-dimensional (3D) composites or composite structures. This is impossible using available fabrication technologies, which are either manufacturing process- assisted only or external field-assisted only. The former is only able to partially align 2D fillers along the direction of a manufacturing path. The latter can only be utilized to align 2D materials suspended in a mold instead of free-form fabrication or printing.

[0120] The effectiveness of sequential dual alignments can be adjusted by controlling the dispensing nozzle geometry and external field setup. The technology' is applicable to a wide range of 2D plate-like materials that are responsive or can be made responsive to external fields as fillers in curable liquid matrix to produce composites or composite structures.

[0121] Some or all of the elements, steps, or components of the approaches described herein can be carried out by a computing device or an apparatus comprising a processor and memory. Examples of such computing devices and apparatuses are described in more detail below.

[0122] As should be appreciated, various embodiments of the present invention may be implemented as methods, apparatus, systems, computing devices, computing entities, and/or the like. As such, embodiments of the present invention may take the form of an apparatus, system, computing device, computing entity, and/or the like executing instructions stored on a computer-readable storage medium to perform certain steps or operations. Thus, embodiments of the present invention may also take the form of an entirely hardware embodiment, an entirely computer program product embodiment, and/or an embodiment that comprises combination of computer program products and hardware performing certain steps or operations.

[0123] Embodiments of the present invention are described below with reference to block diagrams and flowchart illustrations. Thus, it should be understood that each block of the block diagrams and flowchart illustrations may be implemented in the form of a computer program product, an entirely hardware embodiment, a combination of hardware and computer program products, and/or apparatus, systems, computing devices, computing entities, and/or the like carrying out instructions, operations, steps, and similar words used interchangeably (e.g., the executable instructions, instructions for execution, program code, and/or the like) on a computer-readable storage medium for execution. For example, retrieval, loading, and execution of code may be performed sequentially such that one instruction is retrieved, loaded, and executed at a time. In some exemplary embodiments, retrieval, loading, and/or execution may be performed in parallel such that multiple instructions are retrieved, loaded, and/or executed together. Thus, such embodiments can produce specifically-configured machines performing the steps or operations specified in the block diagrams and flowchart illustrations. Accordingly, the block diagrams and flowchart illustrations support various combinations of embodiments for performing the specified instructions, operations, or steps.

[0124] FIG. 1 provides, according to one or more embodiments of the present disclosure, an exemplar}' apparatus 100 for carrying out a sequential dual-alignment approach for planar alignment of two-dimensional (2D) plate-like materials in desired directions in a curable liquid matrix during printing of composites or composite structures. The apparatus 100 comprises a build material reservoir 101 configured to store a supply of a build material, which is also referred to herein as a printing material, an ink, a cross-linkable material, or the like. The build material reservoir 101 can also be configured to communicate volume(s) of the build material to or towards a printing environment. The build material can comprise the curable liquid matrix and the 2D plate-like materials (also called "platelets⁷’ herein) disposed or suspended therein. The apparatus 100 can further comprise a printing nozzle 102 in fluidic communication with the build material reservoir 101. The printing nozzle 102 can be configured to be moved in three dimensions (in the x, y, and z directions) within the printing environment and to dispose discrete volumes or continuous flows of the build material ink to particular locations within the printing environment.

[0125] In some embodiments, the printing nozzle 102 can be configured to exert shear forces on the build material during communication of the build material therethrough. The shear forces can cause an initial alignment or an initial partial alignment of the 2D material (platelets) in the build material, such as along a direction of flow of the build material through the nozzle.

[0126] In some embodiments, the printing environment can be or comprise a yield-stress support bath 103 comprising a yield-stress support material. Said otherwise, the printing nozzle 102 can be configured to dispose volumes or a flow of the build material into the yieldstress support bath 103. The yield-stress support material in the yield-stress support bath 103 can be configured to support (e.g., against deformation) the portions or volumes of build material that are disposed discretely or continuously into the yield-stress support material. Said otherwise, the yield-stress support material can be configured such that the build material can be disposed within a volume of the yield-stress support bath 103 during a first time to achieve a particular size and form factor, and the yield-stress support material can be configured to maintain the size and the form factor of the build material during a second time subsequent to the first time without the need for curing, cross-linking, binding, gelling, solidifying, or otherwise changing the chemical or physical state of the portion of build material being supported in the yield-stress support material.

[0127] More details about yield-stress support materials and freeform additive manufacturing techniques are provided in U.S. Patent No. 10,974,441, U.S. Patent No. 11,426.945, U.S. Patent No. 11,731,343, U.S. Patent No. 11,413,808. U.S. Patent No. 11,724.460, U.S. Patent No. 11.207,841, U.S. Patent No. 11,759,999. U.S. Patent No. 11,724,440, U.S. Patent No. 11,745,412, U.S. Patent Publication No. 2023-0226772, U.S. Patent Publication No. 2021-0236386, U.S. Patent Publication No. 2021-0236697, U.S. Patent Publication No. 2020-0276761, U.S. Patent Publication No. 2023-0256668, U.S. Patent Application No. 18/211,827. U.S. Patent Application No. 18/223,844, and International Patent Application No. PCT/US2023/067838. the entire disclosures of each of which are hereby incorporated herein by reference in their entireties for all purposes.

[0128] Once the build material is communicated into the yield-stress support bath 103, and since the yield-stress support material can maintain the size and form factor of the volume(s) of build material being disposed within the yield-stress support material, an intermediate article can be formed in the yield-stress support bath 103 without curing the curable liquid matrix of the build material. This can be helpful if a further/subsequent alignment or partial alignment of the 2D material (platelets) is desired before curing the curable liquid matrix of the build material in the intermediate article to form a finished article.

[0129] The apparatus 100 can further comprise a rotating element 104 that is operably coupled to the yield-stress support bath 103. In some embodiments, the rotating element 104 can be disposed beneath or about the yield-stress support bath 103 and configured to rotate the entire yield-stress support bath 103 about a center point of the yield-stress support bath 103. In some embodiments, the rotating element 104 can be disposed beneath or about the yield-stress support bath 103 and configured to rotate the entire yield-stress support bath 103 relative to the printing nozzle 102.

[0130] The apparatus 100 can further comprise a field generator 105 that is in operable communication with the yield-stress support bath 103. In some embodiments, the field generator 105 can be configured to generate a field, such as a magnetic field, an electromagnetic field, an electrical field, a radioactive field, or the like. This field generated by the field generator 105 can be communicated towards the yield-stress support bath 103, such as during or after printing of build material from the build material reservoir 101 into the yieldstress support bath 103 using the printing nozzle 102. The field can be configured to initiate or carry out full or partial curing, gelation, cross-linking, or the like on the build material in the yield-stress support bath 103.

[0131] The field exerted by the field generator 105 can be operable to cause a subsequent alignment or a subsequent partial alignment of the 2D material (platelets) in the build material after the volume(s) of build material are disposed/printed into the yield-stress support bath 103. For example, the 2D material (platelets) can comprise or be coated in a field-reactive material that causes the 2D material (platelets) suspended in the curable liquid matrix of the build material to react to the field generated by the field generator 105.

[0132] In some embodiments, the rotating element 104 can be configured to rotate the field generator 105 or a portion thereof, either instead of rotating the yield-stress support bath 103 or in addition to rotating the yield-stress support bath 103. In some embodiments, the rotating element 104 can be configured to rotate the yield-stress support bath 103 initially during printing of the build material into the yield-stress support bath 103 using the printing nozzle 102 in order for the printing nozzle 102 to achieve a desired pathway of travel through the yield-stress support bath 103, and then the rotating element 104 can be configured to rotate the field generator 105 during and/or after printing of the build material in to the yield-stress support bath 103 to achieve the subsequent alignment or partial subsequent alignment of the 2D material (platelets) in the curable liquid matrix of the build material without affecting the size or form factor of the intermediate article.

[0133] Illustration of the sequential dual alignments of 2D material platelets during printing composites and composite structures in a yield-stress support bath, (a) The alignment of 2D platelets before printing: (i) not aligned and (ii) aligned due to printing-induced shear force, (b) The alignment under the external field during and after printing: (i) 2D platelets alignment due to rotating external field, (c) After printing, the printed part is kept in the support bath until fully solidified.

[0134] In some embodiments, the 2D material (platelets) can be or comprise hexagonal boron nitride (hBN), graphene, reduced graphene oxide (rGO) flakes, and/or transition metal dichalcogenides (such as M0S2). These and other similar materials have garnered significant interest since these 2D materials exhibit exceptional electronic, optical, mechanical, and/or thermal properties, making them highly desirable for such applications. The unique structure and properties of these 2D materials contribute to their widespread commercial attention, attributed to their high thermal conductivity, electrical insulation property, exceptional chemical stability, impressive mechanical strength, and/or remarkable oxidation resistance. Consequently, these materials have emerged as promising candidates for various applications, driven by their distinctive characteristics and performance attributes.

[0135] While 2D materials exhibit exceptional properties, these characteristics are predominantly limited to their inherent planes. However, for the development of large-scale macroscopic devices comprising of 2D materials, precise control over the orientation of individual 2D units and their parallel alignment becomes crucial. Achieving planar alignment of 2D materials is essential to effectively represent their unique microscopic properties in such macroscopic structures. For instance, realizing the full potential of highly thermally conductive 2D platelets in functional composites may be hindered by phonon scattering for 2D boron nitride (BN) materials. This scattering can be mitigated through various approaches, including the creation of a robust and immobile interphase, enhancing the filler geometry, establishing a three-dimensional (3D) network, and/or aligning platelets within the composite matrix. Due to the anisotropic nature of thermal conductivity, heat can propagate more efficiently along the in-plane direction compared to the through-plane direction of platelets. Consequently, aligning 2D BN platelets within composites and constructing effective pathways for thermal conduction can significantly enhance heat conductivity, surpassing the values observed in randomly oriented 2D composites.

[0136] In order to form effective networks of ID or 2D fillers in a matrix, various techniques have been developed for their alignment. For ID materials, such as nanotubes and nanorods, they are usually aligned using electrospinning, acoustic field, magnetic field, or mechanical shear force. However, the alignment methods for ID materials may not work well for 2D materials because each 2D material platelet has two degrees of orientational freedom. As such, most of the aforementioned techniques except the rotating magnetic field approach may only result in partial alignment instead of planar alignment for 2D materials. Instead, the alignment of 2D materials (usually as platelets) as fillers in composites has been implemented using the manufacturing process-assisted and external field-assisted approaches.

[0137] The manufacturing process-assisted approach typically utilizes hot pressing or extrusion to introduce a process-induced shear force for alignment. During hot pressing, high pressure is applied to composites with 2D filler materials by two high-temperature rollers. Consequently, the 2D filler materials can be aligned along the in-plane direction, and significant thermal conductivity enhancement can be achieved. While 2D platelets can be pressed to orient along the in-plane direction, only 2D film-like instead of 3D structures can be produced. Besides, elevated temperature and high pressure are required during this process, which not only consumes high energy but also requires good thermal stability for the materials being processed. During extrusion, 2D materials can be aligned along the nozzle moving direction under the printing-induced shear force inside the nozzle. Nevertheless, the conventional printing-induced shear force alignment method is only able to partially align 2D fillers along the nozzle moving direction, resulting in unsatisfactory thermal conductivity.

[0138] On the other hand, the external field-assisted approach ty pically utilizes the electric field and magnetic field alignment methods. Both use an external field to modulate the filler direction, and the alignment can be controlled at arbitrary directions by adjusting the direction of the external field. The electric field alignment method requires a strong dielectric property for material polarization and motion, and the magnetic field alignment method is only effective for magnetic field-responsive materials. For the electric field alignment method, it only results in partial alignment, and the use of an electric field limits the use of polymer matrix due to possible polymer breakdown under high voltage. For the field alignment method, while a static field may result in partial alignment, a rotating field can achieve planar alignment. It should be noted that the effectiveness of the external field-assisted approach is dependent on the state of composite matrix, and it only works when the matrix is liquid and has a relatively low viscosity. The latter makes it challengeable to print 3D structures with aligned 2D fillers since liquid 3D structures cannot maintain their shape during printing.

[0139] As discussed, both the extrusion and electric field methods only result in the partial alignment of 2D filler. While both the hot pressing and field-assisted methods may lead to planar alignment, the former only works for 2D film-like structures and the latter requires a liquid matrix for it to be effective. Despite the tremendous efforts dedicated to developing 2D material alignment methods, as mentioned above, no documented success has been achieved in fabricating intricate 3D parts with planar alignment of 2D filler/platelets.

[0140] In the present disclosure, systems, apparatuses, devices, approaches, methods, and computer program products are described for 3D printing that utilizes a sequential dualalignment mechanism. In some embodiments, a composite ink consisting of 2D platelets and a curable matrix is printed in a yield-stress support bath using a dispensing nozzle to form 3D liquid structures while aligned by the nozzle printing-induced shear force. In some embodiments, the platelets in the deposited liquid structures are further aligned in situ using a rotating external field. Modification of the 2D platelets may be needed or helpful in certain instances in order to induce or increase their responsiveness to a particular external field being exerted during the subsequent/second in situ alignment of the 2D platelets in the intermediate article printed into and supported by the yield-stress support bath material.

[0141] Referring now to FIGs. 2A-2I, an apparatus 200 is illustrated that is configured for sequential dual-alignment of 2D platelets in a composite ink while 3D printing the composite ink into a yield-stress support bath.

[0142] In some embodiments, sequential dual alignment approaches may introduce synergistic effects on platelets, such as hexagonal boron nitride platelets, for superior thermal performance. Planarly aligning 2D platelets is challenging due to their additional orientational freedom compared to ID materials. However, using the apparatus 200, a sequential dualalignment approach, employing an extrusion-printing-induced shear force and rotating- magnetic-field-induced force couple for platelet planarly alignment in a yield-stress support bath, is possible. Without wishing to be bound by any particular theory, the partial alignment, which may be induced by a directional shear force, may facilitate subsequent axial rotation of the platelets for planar alignment under an external force couple, which may result in a synergistic alignment effect. This sequential dual-alignment approach, using the apparatus 200 illustrated in FIG. 2A achieves better planar alignment of 2D modified hexagonal boron nitride (mhBN). Specifically, the thermal conductivity of the 40 wt.% mhBN/epoxy composite is significantly higher (692%) than that of unaligned composites, surpassing the cumulative effect of individual methods (only 133%) with a 5 times more synergistic effect. For composites comprising 30 wt.% mhBN, 40 wt.% mhBN, and 50 wt.% mhBN, the thermal conductivity values (which are, respectively. 5.9 Wm^-1K^-1, 9.5 Wm^-1K^-1, and 13.8 Wm ¹ K ') show considerable improvement compared to the previously known highest values (which were, respectively, 5.3 Wm ¹ K '. 6.6 Wm ¹ K '. and 8.6 Wm ¹ K ¹ )

[0143] The apparatus 200 can be configured to print a variety' of different structures, such as a 3D mhBN/epoxy heat sink. It is demonstrated below that the apparatus 200 can be used to fabricate such devices and enable planar alignment of electrically or thermally conducting 2D fillers during 3D fabrication of articles within a yield-stress support bath.

[0144] 2D plate-like materials, including hexagonal boron nitride (hBN), graphene, reduced graphene oxide flakes, and transition metal dichalcogenides like M0S2, demonstrate outstanding performance in thermal management devices with excellent electronic, optical, mechanical, and thermal properties. Among these 2D materials, hBN has a unique combination of attributes, notably high thermal conductivity, electrically insulating, chemical stability, mechanical strength, and oxidation resistance. Without wishing to be bound by any particular theory', hBN's outstanding in-plane thermal conductivity, =2000 Wm 'k ¹ theoretically, may be attributed to the covalent bond between boron (B) and nitrogen (N) atoms. Moreover, unlike other 2D materials such as graphene and MXenes, BN is electrically insulating due to the wide bandgap (=5.6 eV) with a dielectric constant, low leakage current, and high voltage breakdown strength. Consequently, BN is an effective material in thermal management, particularly in electronic packaging, requiring both thermal conductivity and electrical insulation. Nevertheless, the full potential of hBN in functional composites remains restricted to the in- plane direction of the platelets.

[0145] In the context of large-scale macroscopic devices comprising millions of individual 2D platelets, precise control over the orientation of each platelet is crucial. Aligning the planes of these platelets in parallel may help with minimizing phonon scattering. As heat propagates faster in-plane than through-plane, the planar alignment of BN platelets in composites and the construction of effective thermal conductive pathways to utilize the anisotropic thermal conductivity of hBN presents a promising avenue for enhancing thermal conductivity in composites, surpassing the performance of randomly oriented hBN composites.

[0146] To align and establish effective networks of ID or 2D materials within polymer matrices, various alignment techniques are demonstrated herein. For ID materials like nanotubes and nanorods, electrospinning, acoustic fields, magnetic fields, or mechanical shear forces are typically employed for alignment. However, most of these approaches are ineffective for 2D materials due to their additional degree of orientational freedom, resulting in uniaxial alignment instead of much-needed planar alignment for 2D materials.

[0147] For 2D materials, their alignment is attempted through manufacturing-process- assisted and extemal-field-assisted approaches. The manufacturing-process-assisted approach typically utilizes hot pressing or extrusion printing (including electrospinning as a special case) to introduce a process-induced shear force for alignment. During hot pressing, while 2D platelets can be pressed to orient along a specified in-plane direction by a pressing-induced compressive force, only 2D filmlike instead of 3D structures can be produced. For extrusion printing, 2D materials are oriented within the dispensing nozzle under an extrusion-induced shear force. However, conventional methods of aligning 2D fillers under an extrusion-induced shear force can only achieve partial alignment along the direction of nozzle movement.

[0148] The extemal-field-assisted approach utilizes electric or magnetic fields to generate a force couple to align 2D dielectrically polarized or magnetic materials in arbitrary' directions. For the magnetic field alignment method, while a static-magnetic field (SMF) may result in partial alignment, a rotating magnetic field (RMF, or shortened as magnetic field if not specified) is commonly applied to achieve planar alignment. However, the extemal-field- assisted approach may work best (or only) for 2D materials as fillers in a low-viscosity matrix/medium contained in a mold, and the shape of resulting 3D composite structures is defined by molds.

[0149] The apparatus 200 can be configured to perform a sequential dual-alignment approach is proposed for the planar alignment of modified hexagonal boron nitride (mhBN) platelets, a type of model 2D platelet materials. The sequential dual-alignment approach consists of extrusion-induced shear force alignment and RMF -induced force couple alignment. [0150] First, the apparatus 200 can cause mhBN platelets of a mhBN platelet ink to be partially aligned by the extrusion-induced directional shear force when deposited into a yieldstress support bath to make 3D liquid structures. Second, the apparatus 200 can cause the partially aligned mhBN platelets in the deposited liquid structures to be further aligned in situ for planar alignment by an RMF-induced force couple.

[0151] Without wishing to be bound by any particular theory, the partial alignment of 2D platelets by a directional shear force may facilitate the axial rotation of the platelets for planar alignment under an extemal-force-couple-induced torque and the sequential dual alignments may result in a synergistic alignment effect. Without wishing to be bound by any particular theory, this sequential dual-alignment approach may be made feasible by adopting an advanced 3D printing technology in the apparatus 200 to print the 2D platelet suspension into a liquid 3D structure supported in a yield-stress-based support bath for alignment. The liquid 3D structure is controlled to be completely solidified after the printing and alignment steps are complete, which can be classified as a printing-then-solidification fabrication approach.

[0152] By way of example only, the apparatus 200 can be configured to use composite inks comprising, among other materials, hexagonal boron nitride, which has a single-crystal platelet structure with a mean particle size of 12 pm and a surface area of 2 m² g Additionally or alternatively, a ferrofluid solution containing FesCfi nanoparticles can be used. Additionally or alternatively, an epoxy resin (e.g, 635 thin epoxy resin) and/or a Carbopol powder (e.g., Carbopol 940) can be used.

[0153] Dried mhBN platelets can be dispersed in ethanol at 10 w/v% under probe sonication for 30 min, and epoxy (e.g., 635 thin epoxy system) part A can be added, e.g., at 6.67 w/v%, 10.00 w/v%, 15.56 w/v%, 26.67 w/v%, 60.00 w/v%, and/or other concentrations, into the mhBN suspension. The mixture can then be sonicated for another 30 min. After sonication, the ink can be put onto a magnetic stirring hot plate (e.g., at 500 rpm) to evaporate off the ethanol at 90 °C. Before printing, epoxy part B can be added into the ink at a ratio of part A:part B = 2: 1 and mixed using magnetic stirring at 500 rpm and at room temperature for 5 min to make an ink having a BN concentration of. e.g., 50 w/v%. 40 w/v%, 30 w/v%. 20 w/v%, 10 w/v%. and/or other concentrations, in the final composite ink for panting.

[0154] Magnetically responsive mhBN platelets can be prepared from these mhBN platelets by, for example, suspending 1 g hBN platelets at 2.0 w/v% in deionized (DI) water. Under continuous stirring, the ferrofluid can be incrementally added at 0.2 v/v% into the hBN suspension dropwise and stirred at 400 rpm for 1 h. The suspension can be incubated in an incubating mini shaker at a speed of 350 rpm for 12 h to coat the platelets with Festh nanoparticles from the ferrofluid. Following this, the coated platelets can undergo three consecutive washes with DI water, during which the supernatant can be replaced after platelet precipitation. Subsequently, the magnetized platelets can be subjected to drying at 90°C for a duration of 12 h. After this process, Fe?O4 nanoparticles were attached to the surface of hBN platelets, reflecting the successful synthesis of Fe?O i-coated hBN hybrid composites. The influence of FC3O4 nanoparticles on the mhBN composite thermal conductivity was evaluated. [0155] A yield-stress support bath material, e.g., a Carbopol-based yield-stress support bath material, can be prepared according to a variety of different protocols. For example, an appropriate amount of dry Carbopol powder(s) can be dispersed in DI water with continuous mixing for at least 20 min to ensure thorough hydration of the Carbopol powder(s). The pH value of the Carbopol suspension can be adjusted to neutral by adding aqueous 50% sodium hydroxide for use in the apparatus 200 during printing.

[0156] The apparatus 200 can then be used to print the mhBN/epoxy composite ink in the Carbopol yield-stress support bath with the dual -alignment approach. For example, the apparatus 200 can comprise an extrusion printer with 20-gauge and/or 23-gauge 1 in. long blunt needles having, respectively, an inner diameter of 0.584 mm and 0.330 mm.

[0157] An article for printing using the apparatus 200 can be designed using any suitable software or program. For example, as discussed below, thermal conductivity measurement samples and heat dissipation sinks can be designed using SolidWorks, exported as STL files, and sliced using the embedded Slic3r tools in the Repetrel control software for use by the apparatus 200 (e.g., the Hyrel 3D printer). The printing path speed can be set as 2 mm s '.

[0158] Before printing, the Carbopol support bath can be placed in the middle of a pair of magnets (e.g., grade N52 magnets with a magnetic flux density of 1.48 T), which can be separated by 42 mm and held in a customized rotating stage of the apparatus 200. The rotating stage can be configured to rotate at a speed of 0 (zero) revolutions s ' and 235 revolutions s ', respectively, for SMF and RMF platelet alignment conditions.

[0159] Scanning electron microscopy (SEM) can be used to examine the morphologies of the mhBN/epoxy composite samples. The samples can be quenched in liquid nitrogen and cryofractured perpendicular to the printing directions, coated with gold, and then observed using the SEM at an accelerating voltage of 5 kV.

[0160] Bulk samples with dimensions of 4 mm x 6 mm x 10 mm can be either cast or 3D printed and aligned using the extrusion only, magnetic force couple only, and dual-alignment approach, respectively, for testing. The alignment of mhBN platelets in epoxy can be evaluated and confirmed XRD at 45 kV and 40 mA. Samples can be irradiated from 5.1° to 90° at the same X-ray penetration depth. The step size can be set as 0.0016°, and the time per step can be 10 seconds.

[0161] Thermal conductivity of example printed samples can be determined using a comparative cut bar technique. Samples measuring 4 mm x 6 mm x 10 mm can be positioned between two standard aluminum (Al) blocks with a known thermal conductivity value of 200.0 Wm ¹ K A heating plate can serve as the heat source, ensuring a consistent heat flow through the Al blocks. To eliminate air gaps, a thin layer (<500 pm) of thermal paste can be applied between the sample and Al blocks. The thermal conductivity measurements can be taken along the in-plane direction, which is parallel to the printing direction and/or the plane swept by the magnetic field. Additionally or alternatively, through-plane direction thermal conductivity measurements can be conducted perpendicular to the printing direction and/or the plane swept by the magnetic field. Temperature distribution along the heat flow direction can be recorded using an IR camera with a resolution of 320 x 240 pixels.

[0162] Heat conducted from the bottom Al block to the top heat sink through the sample sandwiched betw een the Al blocks can provide insight into the heat-conducting capability of the samples. Pseudocolor images captured by the IR camera can be processed using MATLAB to extract temperatures of interest. Lowber temperatures at the bottom Al block can indicate better heat dissipation of the composite sample.

[0163] The thermal conductivity’ of the samples can be calculated through a combination of SolidWorks simulations and experimental data analysis, following a previously established methodology. The SolidWorks model can employ a finite element method to solve the 3D heat conduction equation tailored to match the experimental setup. Boundary conditions accounting for radiation and natural convection can be integrated into the model to simulate temperature distributions within the samples. The top surface of the uppermost Al block can be applied with a temperature boundary condition equivalent to the room temperature (~22 °C) as measured by the IR camera. The heat flow’ from the heating unit can be calculated using the equation Q = U x I x e, where U and I represents the voltage and current of the direct current power supply (e.g. 3.78 V and 0.38 A, respectively), and e denotes the emissivity of the coated Al surface (e.g., 0.8). According to some examples, Q = 3.78 V x 0.38 A x 0.8 = 1.15 W. The thermal conductivity of the sample can be iteratively adjusted in the model until the resulting temperature distribution aligns with experimental measurements. Through this iterative process, the thermal conductivity values of the samples can be determined.

[0164] To characterize the dielectric properties of mhBN/epoxy composite samples fabricated using the dual-alignment and other alignment methods, the mhBN/epoxy composite samples can be polished to yield a flat surface, and the dimensions can be recorded accordingly. Before measurement, the top and bottom surfaces can be painted with a thin layer of silver conductive paint to serve as electrodes. The dielectric properties (e.g, dielectric constant and dissipation factor) can be measured using a precision LCR meter with frequencies varying from 100 Hz to 1 MHz and an alternating current voltage of 1 V.

[0165] RStudio software can be used for statistical analysis. Group differences can be assessed utilizing one-way analysis of variance (ANOVA) with a Tukey post hoc test for multiple comparisons with a significant level of a = 0.05. Data can be expressed as mean ± standard deviation, with a minimum sample size of n > 3 being used, unless otherwise specified.

[0166] As illustrated in FIG. 2B, the 3D printed structure can be printed into the yieldstress support bath under RMF conditions, or alternatively, as illustrated in FIG. 2C, the 3D printed structure can be printed into the yield-stress support bath under SMF conditions. In some embodiments, the apparatus 200 can be configured for SMF conditions, while in other embodiments the apparatus 200 can be configured for RMF conditions, and in still other embodiments, the apparatus 200 can be configured for both SMF conditions and RMF conditions.

[0167] As illustrated in FIG. 2D, the solidified printed structure, once solidified, can be removed from the yield-stress support bath of the apparatus 200. The solidified printed structure, once solidified or partially solidified, can retain the platelet alignment conditions and alignment orientations previously imbued or affected on the printed structure, whether via an initial nozzle-based shear force-induced alignment, a secondary post-printing SMF alignment, a secondary post-printing RMF alignment, or combinations thereof.

[0168] In some embodiments, the apparatus 200 can be configured to apply an initial nozzle-based shear force-induced alignment to all printed ink during printing and to selectively apply either secondary SMF alignment or secondary RMF alignment during only a portion of the printing process. For example, the apparatus 200 can be configured to 3D print a structure into a yield-stress support bath using, sequentially, two or more different inks, e.g, including one or more inks that are non-magnetic and one or more inks that are magnetic. If the apparatus 200 were to attempt to apply either secondary SMF alignment or secondary RMF alignment after printing using the non-magnetic ink, no secondary alignment of platelets in the non-magnetic ink would take place. As such, the apparatus 200 can be configured to apply SMF or RMF alignment to magnetic inks during or just following their extrusion/printing into the yield-stress support bath, and further can be configured to refrain from applying SMF or RMF alignment to non-magnetic inks.

[0169] Alternatively, as illustrated in FIGs. 2E, 2F, 2G, 2H, and 21, the apparatus 200 can be configured to perform a print-then-align approach in which the apparatus 200 carries out printing of all portions of the article into the yield-stress support bath and then applies secondary SMF or RMF alignment to the printed article before curing or partially curing the printed article retained against deformation within the yield-stress support bath.

[0170] As illustrated in the A-A view box of FIG. 2F, before extrusion/printing is carried out, there may be no alignment or only localized and incidental alignment of platelets or other 2D structures suspended within the printing ink resin. However, as illustrated in the B-B view box of FIG. 2F, the initial nozzle-based shear force-induced alignment can at least partially align the platelets or other 2D structures suspended within the printing ink resin once the printing ink resin enters the nozzle and/or as the printing ink resin travels through the nozzle towards the extrusion tip.

[0171] Then, once the printed article is fully extruded into the yield-stress support bath, the apparatus 200 can cause rotation of the magnetic field generation means, thereby exerting the RMF on the printed article and causing the secondary RMF-based alignment of the platelets or 2D structures in the printing ink resin of the printed article within the yield-stress support bath. The materials chosen for the resin and for the yield-stress support bath can be carefully chosen so as to not interfere with the SMF or RMF alignment of the platelets or other 2D structures in the ink and so as to not be detrimentally impacted or affected by the SMF or RMF magnetic alignment process.

[0172] FIG. 3 illustrates one example for technological implementation of a yield-stress support bath-enabled sequential dual -alignment approach 300 (“approach 300 ). according to certain embodiments. The approach 300 can include, generally, three steps with several other preliminary' steps or terminal steps contemplated. The three main steps can be considered to be composite ink preparation, printing-assisted alignment in a yield-stress support bath, and external rotating field-assisted alignment in a yield-stress support bath. Preliminarily, the approach 300 can include the providing of a 2D material (platelets), at 301. The 2D material (platelets) can, optionally, be modified, at 302, such as by coating the 2D material (platelets) with a field-reactive material or otherwise causing the 2D material (platelets) to be reactive to a specific external field in order that the 2D material (platelets) can be subsequently aligned during and/or after printing of the intermediate article in the yield-stress support bath.

[0173] The approach 300 can further include providing a curable liquid matrix, at 303, that is configured to remain liquid during and after printing of the intermediate article, but which is curable at a subsequent time without having to remove the intermediate article from the yieldstress support bath material. The approach 300 can further include composite ink preparation, at 304, dunng which the 2D material (platelets), whether modified 302 or not, are communicated into, suspended within, dispersed within, homogenized within, or otherwise disposed within the curable liquid matrix, to form the build material.

[0174] In some embodiments, the build material (also called a composite ink herein) can be made of a plurality of 2D plate-like particles of a particular material (platelets), a curable liquid matrix material, and/or other additives, fillers, modifiers, rheological agents, or the like, as deemed necessary' for specific applications. In some embodiments, the responsiveness of raw 2D material to external fields can be evaluated. If the material is initially non-responsive, the material modification, at 302, may be required to make the 2D platelets responsive to a particular external field to be used for subsequent alignment of the 2D platelets. This can be achieved by coating the surface of 2D material platelets with smaller particles that are responsive to an external field. In some embodiments, ultrasonication of 2D platelets in the curable liquid matrix can be carried out to facilitate homogeneous dispersion of the 2D platelets in the curable liquid matrix to form the build material.

[0175] The approach 300 can further include printing-assisted alignment, at 305, of the 2D material (platelets) in the build material, such as by communicating the build material through a printing nozzle (e.g., 102) that exerts forces, such as shear forces, on the build material, causing an initial alignment or an initial partial alignment of the 2D material (platelets) within the build material.

[0176] Yield-stress fluids have the ability to maintain the printed shape and retain the printed structure in them during embedded printing in a yield-stress support bath. The selection of a specific support bath may depend at least in part on the requirements of the build material being printed into it, such as whether the build material is hydrophilic or hydrophobic, and/or other properties of the build material. In 305, one or more of different dispensing nozzles (e.g, 102) with different geometries can be employed to control the resulting printing-induced shear force, thus the alignment performance. The printing-induced shear force introduces the initial alignment/orientation (or partial alignment/orientation) of the 2D platelets as partial alignment in the composite matrix ink along the printing direction while the ink is being dispensed through the nozzle.

[0177] The approach 300 can further include external field-assisted alignment, at 306. In some embodiments, in 306, once the build material is deposited in the yield-stress support bath (e.g. , 103), the yield-stress support bath can be capable of trapping the deposited build material in situ and maintaining the printed 3D shape. This allows the 2D material platelets to be further aligned planarly during the printing and post-printing phases under the rotating external field such as a magnetic or electrical field, which is employed as the secondary' alignment method in this sequential dual-alignment approach. The yield-stress support bath ensures the structural integrity of printed objects while they undergo additional alignment under a rotating external field, and the rotating external field assists in further aligning the 2D material platelets, enhancing the overall alignment effect. Once the sequential alignment, during printing at 305 and after printing at 306, is complete, an intermediate article is formed in the yield-stress support bath.

[0178] The approach 300 can further include solidification, at 307, of the intermediate article. Depending on the selection of curable liquid matrix materials, they' may start solidifying once a composite ink is made or under additional post-alignment stimulation. In instances in which initial or full solidification of the composite ink (curable liquid matrix) proceeds automatically during a time following preparation of the composite ink, at 304, the printing and alignment time may be controlled within a solidification window of the composite ink. After complete solidification, printed composites or composite structures are taken out of the support bath for further cleaning.

[0179] Referring now to FIGs. 4A-4D, a 3D printing apparatus 400 is illustrated. The 3D printing apparatus 400 is configured for carrying out sequential dual-alignment 3D printing of inks comprising mhBN platelets. The 3D printing apparatus 400 is configured to utilize extrusion-printing-induced shear force for an initial alignment during printing and RMF- induced magnetic force couple after mhBN structure printing for a secondary alignment. Because mhBN can be sterically stabilized by polymers during ultrasonication in a solution, a homogeneous dispersion can be made. Good orientation of mhBN platelets in composite matrix ink can form energetic pathways for phonon conduction. The sequential dual -alignment approach is enabled by the yield-stress property of the support bath, which is utilized for mhBN structure printing. This property allows the support bath, such as a Carbopol microgel bath, to trap the extruded ink in situ and retain the printed shape in a 3D structure even though the ink has low viscosity. This allows deposited 2D materials in 3D structures to be further aligned under a magnetic field during the printing and post-printing phases.

[0180] In some embodiments, the Carbopol support bath does not affect the epoxy curing process and ink viscosity since it does not interfere with the cross-linking process of epoxy.

[0181] As noted above, in some examples, the apparatus 400 can be configured to perform a support-bath-enabled sequential dual-alignment printing process can comprise modifying the hBN to be magnetic force responsive by coating a layer of magnetic-field-responsive materials, such as iron oxide (FesO-i) nanoparticles, on the surface of hBN platelets as magnetic hBN. Validation of the mhBN platelets’ magnetic response is discussed in greater detail below. The composition of the mhBN/epoxy composite ink can be validated with elemental analysis, the results of which are discussed in greater detail below noted in Table 1. Before printing, a model Carbopol microgel support bath can be placed in the middle of a pair of magnets and held in the rotating stage of the apparatus 400, as illustrated in FIG. 4A, to create an RMF condition. A printed structure is fabricated by extruding a mhBN-based composite ink into the Carbopol support bath. The mhBN platelets dispersed in the composite ink are first randomly aligned before entering the dispensing nozzle, as illustrated in the A-A view box in FIG. 4B.

[0182] During the extrusion process, due to the extrusion-induced shear effect consistently applied by the dispensing nozzle’s inner wall, the platelets can be first aligned parallelly to the filament’s axial direction when being extruded through the dispensing nozzle, as illustrated in the B-B view box in FIG. 4B. After being extruded from the dispensing nozzle and deposited into the Carbopol support bath, as illustrated in FIG. 4D, the printed filament remains liquid. The printed structure holds its overall shape as supported by the Carbopol bath, while each mhBN platelet can still be manipulated to change its orientation under the effect of the external magnetic field. With the continuous effect of varying magnetic field conditions, the SMF keeps applying a static alignment force in the magnetic field force direction, as illustrated in the SMF box in FIG. 4C. Under the RMF condition, the mhBN platelets are gradually aligned horizontally with the assistance of continuous sweeping of the RMF in the x-y plane, as illustrated in the RMF box in FIG. 4C. The longer the exposure time of the magnetic field, the more pronounced the effect of the mhBN alignment. The printed part is kept under the magnetic field until fully solidified, as illustrated in FIG. 4C. After complete solidification, as illustrated in FIG. 4D, the 3D structure is removed from the support bath and cleaned using an ultrasonic bath to remove any residual Carbopol. The detailed experimental setup for this 3D sequential printing approach is described in the Experimental Section and detailed in Section S3 (Supporting Information). FIG. 4D illustrates typical alignment results for individual extrusion- and magnetic-field-induced alignment and that of the proposed sequential dual-alignment approach, which are further explored in the following sections.

[0183] Refernng now to FIGs. 5A-5E, a sequential dual-alignment 3D printing approach 500 is illustrated for printing a 3D heat sink from a mhBN/epoxy composite ink. Also illustrated is the thermal management performance of the 3D printed heat sinks, as compared with control parts. During the sequential dual-alignment 3D printing approach 500, the mhBN platelets are first aligned by the extrusion force and then aligned in the horizontal plane by the RMF-induced force couple, resulting in the planar alignment perpendicular to the bottom surface of the heat sink, w hich interfaces with simulated electronic devices.

[0184] After the heat sink is printed and solidified, it is placed on the flat surface of the simulated electronic device (heating plate). The mhBN platelets perpendicularly aligned to the heat sink bottom surface can effectively conduct heat away from the bottom to the heat sink fins for dissipation.

[0185] FIG. 6 illustrates a schematic of an experiment setup 600 for testing the heat dissipation performance of heat sinks printed according to the sequential dual-alignment 3D printing approach 500. Using the experimental setup 600, heat sink performance was evaluated with a constant 1.15 W power input, and with a controlled constant temperature of 70° C on the heating plate. Since both extrusion-induced and SMF-induced alignment mechanisms can only align platelets in one dimension and demonstrate similar performance, the sample prepared using the extrusion printing-induced alignment was chosen as a representative one for further analysis. On the other hand, the sample without alignment was prepared through casting. All heat sink samples share the same dimensions of 10 mm * 10 mm x 7 mm (width x length x height) and were individually subjected to a constant power or temperature of 70° C for 300 seconds on an isothermal heating plate to ensure a state of thermal equilibrium. To evaluate the thermal management efficiency of the heat sinks fabricated using different alignment mechanisms, an infrared thermal (IR) camera was employed as part of the experimental setup 600 to record the surface temperature variations of the composites during the heating process. The IR camera was positioned on top of the heat sink, capturing the temperature changes over time.

[0186] FIG. 7 provides an array of infrared (IR) images of heat dissipation performance of a control (heating plate only) and 40 wt.% mhBN heat sinks fabricated according to the sequential dual-alignment 3D printing approach 500 using either no alignment approach, a single alignment approach, or a dual-alignment approach. Before capturing the IR images of the control plates and 3D printed heat sinks, the heat sinks were heated up from room temperature using heating plates placed beneath them. Initially, all IR images are uniformly black, indicating that the temperatures across the heat sinks and heating plate are the same as room temperature (22 °C). As time progresses, the surface temperatures of both the heating plate and heat sinks increase, and their temperature differences become evident among the different heat sinks and the heating plates beneath them. In the absence of any heat sink (the control), the heating plate consistently maintains the highest temperature at each measurement point. Conversely, the group with the heat sinks exhibits lower temperatures on the heating plate, showing that more heat is dissipated during the process. Notably, the heat sink printed using the dual-alignment approach consistently exhibits the highest top surface temperature of the fins among the three heat sinks at different measurement intervals, while simultaneously maintaining the lowest temperature on the heating plate beneath it. After about 200 seconds, the temperatures on the fins of the heat sinks are 25 °C, 31 °C, and 34 °C for those fabricated with no alignment, extrusion-only alignment, and dual-alignment approaches, respectively, while the temperatures of the heating plates are 38 °C, 37 °C, and 35 °C, respectively. For comparison, the control shows 40 °C. The good heat dissipation performance of the dually aligned heat sink is attributed to planarly aligned mhBN platelets (vertically oriented in this case), which significantly improve the overall thermal conductivity. The superior heat transfer efficiency demonstrated by this heat sink, as compared to that of the heat sink produced using the single-alignment approach, exemplifies its potential for deployment as an effective thermal management device.

[0187] FIGs. 8 and 9 depict temperature changes on a fin top surface of the heat sinks fabricated according to the sequential dual-alignment 3D printing approach 500 during, respectively, heating or cooling processes and using a consistent heating plate temperature.

[0188] Notably, the heat sink made with the dual -alignment approach exhibits the most rapid increase and decrease in temperature, reaching a steady-state temperature after 90 s of heating and 80 s of cooling. By contrast, the heat sinks with the single alignment and no alignment approaches require longer durations to reach the steady-state temperature. Specifically, the single-alignment heat sink made using the single-alignment approach takes =170 s for heating and 120 s for cooling, and the heat sink made using the no-alignment approach requires around 290 s for heating and 180 s for cooling to reach the static state temperature. These results indicate that the heat sink made using the dual-alignment approach is more efficient in conducting heat away (about 2.0 times faster for heating and 1.5 times faster for cooling when compared with that of the singly aligned heat sink).

[0189] Existing heat management devices are ty pically constrained by single alignment approaches, either only being able to produce 2D film devices or being unable to align within arbitrarily 3D-shaped structures, thus compromising the resulting thermal conductivity in 3D structures. The sequential dual-alignment 3D printing approach 500 can print arbitrarily 3D- shaped structures such as the illustrated 3D heat sinks, resulting in more efficient heat dissipation performance. Without wishing to be bound by any particular theory, this improvement may be attributable to two factors: the increased fin surface area (arbitrarily 30- shaped) enabled by embedded 3D printing and the enhanced thermal conductivity' achieved by applying the dual-alignment approach.

[0190] As noted, the sequential dual-alignment 3D printing approach 500 is an in situ approach for planar alignment of 2D platelets using initial alignment due to directional shear force exerted by the dimensions and form factor of the extrusion nozzle on the ink and secondary alignment under an external force-couple moment in 3D structures during fabrication. In some embodiments, the sequential dual-alignment 3D printing approach 500 can comprise extrusion-induced shear force alignment and RMF -induced force couple alignment. In some embodiments, the post-printing magnetic-force-couple-induced alignment process is an addition to the directional extrusion-induced shear force alignment. 2D platelets that are uniaxially aligned by the shear force along the printing direction can be further planarly aligned along the plane of RMF. The sequential dual-alignment 3D printing approach 500 is made feasible by, among other factors and features, printing the 2D platelet suspension into a liquid 3D structure supported in a yield-stress-based support bath for alignments. The partial alignment of 2D platelets by a directional shear force facilitates the axial rotation of the platelets for planar alignment under an extemal-force-couple-induced torque and the sequential dual alignments result in a synergistic alignment effect. [0191] As demonstrated in mhBN/epoxy composite printing, the thermal conductivity of the 40% mhBN composites aligned using the dual -alignment approach is 692% higher than that of unaligned composites and outperforming the sum when using two individual methods collectively (133% improvement only) by more than 5 times, meaning a 5 times more synergistic effect.

[0192] The dual-alignment approach results in the highest TEF at 30 wt.% mhBN concentration of 760% and the highest thermal conductivity of 13.8 Wm ¹ K ¹ at 50 wt.% mhBN concentration. A 3D thermal management device is fabricated, which further demonstrates the flexibility of creating 3D structures with aligned mhBN platelets using this dual-alignment approach for improved thermal conduction performance.

[0193] The aforementioned results indicate the achievement of superior thermal conductivity using either alignment method alone is trivial because of the limitations of each method in their permissible range. The dual-alignment approach helps resolve this challenge by synergistically utilizing the extrusion-induced shear force for one-directional pre-alignment and the RMF-induced force couple for planar alignment to increase the degree of planar alignment and therefore reduce the interfacial thermal resistance, leading to the exceptional thermal conductivity⁷ of mhBN/epoxy composite samples. The ability to align electrically or thermally conducting 2D materials in situ and fabricate complex structures enables the incorporation of aligned 2D material fillers in 3D structures. For large-scale printing, it is important to resolve the challenge between early solidification of ink and sufficient alignment of 2D fillers in deposited ink, which may be overcome by using cross-linking retarders and/or adopting segmented printing.

[0194] Some or all of the methods, approaches, printing processes, and/or the like described herein can be carried out in part or in full by a computing device or computer- controlled apparatus. Some embodiments of the present invention may be implemented in various ways, including as computer program products that comprise articles of manufacture. Such computer program products may include one or more software components including, for example, software objects, methods, data structures, or the like. A software component may be coded in any of a variety of programming languages. An illustrative programming language may be a lower-level programming language such as an assembly language associated with a particular hardware architecture and/or operating system platform. A software component comprising assembly language instructions may require conversion into executable machine code by an assembler prior to execution by the hardware architecture and/or platform. Another example programming language may be a higher-level programming language that may be portable across multiple architectures. A software component comprising higher-level programming language instructions may require conversion to an intermediate representation by an interpreter or a compiler prior to execution.

[0195] Other examples of programming languages include, but are not limited to, a macro language, a shell or command language, a job control language, a script language, a database query or search language, and/or a report writing language. In one or more example embodiments, a software component comprising instructions in one of the foregoing examples of programming languages may be executed directly by an operating system or other software component without having to be first transformed into another form. A software component may be stored as a file or other data storage construct. Software components of a similar type or functionally related may be stored together such as, for example, in a particular directory, folder, or library'. Software components may be static (e.g., pre-established or fixed) or dynamic (e.g., created or modified at the time of execution).

[0196] A computer program product may include a non-transitory computer-readable storage medium storing applications, programs, program modules, scripts, source code, program code, object code, byte code, compiled code, interpreted code, machine code, executable instructions, and/or the like (also referred to herein as executable instructions, instructions for execution, computer program products, program code, and/or similar terms used herein interchangeably). Such non-transitory computer-readable storage media include all computer-readable media (including volatile and non-volatile media).

[0197] In one embodiment, a non-volatile computer-readable storage medium may include a floppy disk, flexible disk, hard disk, solid-state storage (SSS) (e.g., a solid-state drive (SSD), solid state card (SSC), solid state module (SSM), enterprise flash drive, magnetic tape, or any other non-transitory magnetic medium, and/or the like. A non-volatile computer-readable storage medium may also include a punch card, paper tape, optical mark sheet (or any other physical medium with patterns of holes or other optically recognizable indicia), compact disc read only memory (CD-ROM), compact disc-rewritable (CD-RW), digital versatile disc (DVD), Blu-ray disc (BD), any other non-transitory optical medium, and/or the like. Such anon-volatile computer-readable storage medium may also include read-only memory' (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory (e.g. , Serial. NAND, NOR, and/or the like), multimedia memory cards (MMC), secure digital (SD) memory cards, SmartMedia cards, CompactFlash (CF) cards, Memory Sticks, and/or the like. Further, a non-volatile computer-readable storage medium may also include conductive-bridging random access memory (CBRAM), phase-change random access memory (PRAM), ferroelectric random-access memory (FeRAM), non-volatile randomaccess memory (NVRAM), magnetoresistive random-access memory (MRAM), resistive random-access memory (RRAM), Silicon-Oxide-Nitride-Oxide-Silicon memory (SONOS), floating junction gate random access memory' (FJG RAM), Millipede memory', racetrack memory, and/or the like.

[0198] In one embodiment, a volatile computer-readable storage medium may include random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), fast page mode dynamic random access memory' (FPM DRAM), extended data-out dynamic random access memory (EDO DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), double data rate type two synchronous dynamic random access memory (DDR2 SDRAM), double data rate type three synchronous dynamic random access memory' (DDR3 SDRAM), Rambus dynamic random access memory (RDRAM), Twin Transistor RAM (TTRAM), Thyristor RAM (T-RAM), Zero-capacitor (Z-RAM), Rambus inline memory module (R1MM), dual in-line memory module (DIMM), single in-line memory module (SIMM), video random access memory' (VRAM), cache memory (including various levels), flash memory⁷, register memory', and/or the like. It will be appreciated that where embodiments are described to use a computer-readable storage medium, other ty pes of computer-readable storage media may be substituted for or used in addition to the computer- readable storage media described above.

[0199] FIG. 10 provides a schematic of such a computing device 700 according to one embodiment of the present invention. In general, the terms computing device, computing entity, computer, entity, device, system, and/or similar words used herein interchangeably may refer to, for example, one or more computers, computing entities, desktops, mobile phones, tablets, phablets, notebooks, laptops, distributed systems, kiosks, input terminals, servers or server networks, blades, gateways, switches, processing devices, processing entities, set-top boxes, relays, routers, network access points, base stations, the like, and/or any combination of devices or entities adapted to perform the functions, operations, and/or processes described herein. Such functions, operations, and/or processes may include, for example, transmitting, receiving, operating on, processing, displaying, storing, determining, creating/generating, monitoring, evaluating, comparing, and/or similar terms used herein interchangeably. In one embodiment, these functions, operations, and/or processes can be performed on data, content, information, and/or similar terms used herein interchangeably.

[0200] As shown in FIG. 10, in one embodiment, the computing device 700 may include or be in communication with one or more processing elements 702 (also referred to as processors, processing circuitry, and/or similar terms used herein interchangeably) that communicate with other elements within the computing device 700 via a bus, for example. As will be understood, the processing element 702 may be embodied in a number of different ways. For example, the processing element 702 may be embodied as one or more complex programmable logic devices (CPLDs), microprocessors, multi-core processors, coprocessing entities, application-specific instruction-set processors (ASIPs), microcontrollers, and/or controllers. Further, the processing element 702 may be embodied as one or more other processing devices or circuitry. The term circuitry may refer to an entirely hardware embodiment or a combination of hardware and computer program products. Thus, the processing element 702 may be embodied as integrated circuits, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), hardware accelerators, other circuitry, and/or the like. As will therefore be understood, the processing element 702 may be configured for a particular use or configured to execute instructions stored in volatile or non-volatile media or otherwise accessible to the processing element 702. As such, whether configured by hardware or computer program products, or by a combination thereof, the processing element 702 may be capable of performing steps or operations according to embodiments of the present invention when configured accordingly.

[0201] In one embodiment, the computing device 700 may further include or be in communication with non-volatile media (also referred to as non-volatile storage, memory, memory storage, memory circuitry and/or similar terms used herein interchangeably). In one embodiment, the non-volatile storage or memory may include one or more non-volatile storage or memory media 703, including but not limited to hard disks, ROM, PROM, EPROM, EEPROM, flash memory⁷, MMCs, SD memory⁷ cards, Memory⁷ Sticks, CBRAM, PRAM, FeRAM, NVRAM, MRAM, RRAM, SONOS, FJG RAM, Millipede memory, racetrack memory, and/or the like. As will be recognized, the non-volatile storage or memory media may store databases, database instances, database management systems, data, applications, programs, program modules, scripts, source code, object code, byte code, compiled code, interpreted code, machine code, executable instructions, and/or the like. The term database, database instance, database management system, and/or similar terms used herein interchangeably may refer to a collection of records or data that is stored in a computer-readable storage medium using one or more database models, such as a hierarchical database model, network model, relational model, entity-relationship model, object model, document model, semantic model, graph model, and/or the like.

[0202] In one embodiment, the computing device 700 may further include or be in communication with volatile media (also referred to as volatile storage, memory, memory storage, memory circuitry and/or similar terms used herein interchangeably). In one embodiment, the volatile storage or memory may also include one or more volatile storage or memory media 704, including but not limited to RAM, DRAM, SRAM. FPM DRAM, EDO DRAM, SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, TTRAM, T- RAM, Z-RAM, RIMM, DIMM, SIMM, VRAM, cache memory, register memory, and/or the like. As will be recognized, the volatile storage or memory media may be used to store at least portions of the databases, database instances, database management systems, data, applications, programs, program modules, scripts, source code, object code, byte code, compiled code, interpreted code, machine code, executable instructions, and/or the like being executed by, for example, the processing element 702. Thus, the databases, database instances, database management systems, data, applications, programs, program modules, scripts, source code, object code, byte code, compiled code, interpreted code, machine code, executable instructions, and/or the like may be used to control certain aspects of the operation of the computing device 700 with the assistance of the processing element 702 and operating system. [0203] In some embodiments, the computing device 700 may also include one or more network interfaces, such as a transceiver 708 for communicating with various computing entities, such as by communicating data, content, information, and/or similar terms used herein interchangeably that can be transmitted, received, operated on, processed, displayed, stored, and/or the like. Such communication may be executed using a wired data transmission protocol, such as fiber distributed data interface (FDDI), digital subscriber line (DSL), Ethernet, asynchronous transfer mode (ATM), frame relay, data over cable service interface specification (DOCSIS), or any other wired transmission protocol. Similarly, the computing device 700 may be configured to communicate via wireless external communication networks using any of a variety of protocols, such as general packet radio service (GPRS), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA2000), CDMA2000 IX (IxRTT), Wideband Code Division Multiple Access (WCDMA), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), Time Division-Synchronous Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), Evolution-Data Optimized (EVDO), High Speed Packet Access (HSPA), High-Speed Downlink Packet Access (HSDPA), IEEE 802. 11 (Wi-Fi), Wi-Fi Direct, 802.16 (WiMAX), ultra-wideband (UWB), infrared (IR) protocols, near field communication (NFC) protocols, Wibree, Bluetooth protocols, wireless universal serial bus (USB) protocols, and/or any other wireless protocol.

[0204] Although not shown, the computing device 700 may include or be in communication with one or more input elements, such as a keyboard input, a mouse input, a touch screen/display input, motion input, movement input, audio input, pointing device input, joystick input, keypad input, and/or the like. The computing device 700 may also include or be in communication with one or more output elements (not shown), such as audio output, video output, screen/display output, motion output, movement output, and/or the like.

[0205] FIG. 11 provides an illustrative schematic representative of an external computing device 800 that can be used in conjunction with embodiments of the present invention. In general, the terms device, system, computing entity, entity, and/or similar words used herein interchangeably may refer to, for example, one or more computers, computing entities, desktops, mobile phones, tablets, phablets, notebooks, laptops, distributed systems, kiosks, input terminals, servers or server networks, blades, gateways, switches, processing devices, processing entities, set-top boxes, relays, routers, network access points, base stations, the like, and/or any combination of devices or entities adapted to perform the functions, operations, and/or processes described herein. External computing entities 800 can be operated by various parties. As shown in FIG. 9, the external computing device 800 can include an antenna 808, a transmitter 809 (e g., radio), a receiver 810 (e g., radio), and a processing element 802 (e.g, CPLDs, microprocessors, multi-core processors, coprocessing entities, ASIPs, microcontrollers, and/or controllers) that provides signals to and receives signals from the transmitter 809 and receiver 810, correspondingly.

[0206] The signals provided to and received from the transmitter 809 and the receiver 810, correspondingly, may include signaling information/data in accordance with air interface standards of applicable wireless systems. In this regard, the external computing device 800 maybe capable of operating with one or more air interface standards, communication protocols, modulation types, and access types. More particularly, the external computing device 800 may operate in accordance with any of a number of wireless communication standards and protocols, such as those described above with regard to the computing device 700. In a particular embodiment, the external computing device 800 may operate in accordance with multiple wireless communication standards and protocols, such as UMTS, CDMA2000, IxRTT, WCDMA, GSM, EDGE, TD-SCDMA, LTE, E-UTRAN, EVDO, HSPA, HSDPA, Wi-Fi, Wi-Fi Direct, WiMAX, UWB, IR, NFC, Bluetooth, USB, and/or the like. Similarly, the external computing device 800 may operate in accordance with multiple wired communication standards and protocols, such as those described above with regard to the computing device 800 via a network interface 806.

[0207] Via these communication standards and protocols, the external computing device 800 can communicate with various other entities using concepts such as Unstructured Supplementary Service Data (USSD), Short Message Service (SMS), Multimedia Messaging Service (MMS), Dual-Tone Multi-Frequency Signaling (DTMF), and/or Subscriber Identity Module Dialer (SIM dialer). The external computing device 800 can also download changes, add-ons, and updates, for instance, to its firmware, software (e.g., including executable instructions, applications, program modules), and operating system.

[0208] According to one embodiment, the external computing device 800 may include location determining aspects, devices, modules, functionalities, and/or similar words used herein interchangeably. For example, the external computing device 800 may include outdoor positioning aspects, such as a location module adapted to acquire, for example, latitude, longitude, altitude, geocode, course, direction, heading, speed, universal time (UTC), date, and/or various other information/data. In one embodiment, the location module can acquire data, sometimes known as ephemeris data, by identifying the number of satellites in view and the relative positions of those satellites (e.g., using global positioning systems (GPS)). The satellites may be a variety of different satellites, including Low Earth Orbit (LEO) satellite systems, Department of Defense (DOD) satellite systems, the European Union Galileo positioning systems, the Chinese Compass navigation systems. Indian Regional Navigational satellite systems, and/or the like. This data can be collected using a variety of coordinate systems, such as the Decimal Degrees (DD); Degrees, Minutes, Seconds (DMS); Universal Transverse Mercator (UTM); Universal Polar Stereographic (UPS) coordinate systems; and/or the like. Alternatively, the location information/data can be determined by triangulating a position of the external computing entity 800 in connection with a variety of other systems, including cellular towers, Wi-Fi access points, and/or the like. Similarly, the external computing device 800 may include indoor positioning aspects, such as a location module adapted to acquire, for example, latitude, longitude, altitude, geocode, course, direction, heading, speed, time, date, and/or various other information/data. Some of the indoor systems may use various position or location technologies including RFID tags, indoor beacons or transmitters, Wi-Fi access points, cellular towers, nearby computing devices (e.g., smartphones, laptops) and/or the like. For instance, such technologies may include the iBeacons, Gimbal proximity beacons. Bluetooth Low Energy’ (BLE) transmitters, NFC transmitters, and/or the like. These indoor positioning aspects can be used in a variety of settings to determine the location of someone or something to within inches or centimeters.

[0209] The external computing device 800 may also comprise a user interface (that can include a display 807 coupled to the processing element 802) and/or a user input interface (coupled to the processing element 802). For example, the user interface may be a user application, browser, user interface, and/or similar words used herein interchangeably executing on and/or accessible via the external computing device 800 to interact with and/or cause display of information/data from the computing device 800, as described herein. The user input interface can comprise any’ of a number of devices or interfaces allowing the external computing device 800 to receive data, such as a keypad 811 (hard or soft), a touch display, voice/speech or motion interfaces, or other input device. In embodiments including a keypad 811, the keypad 811 can include (or cause display of) the conventional numeric (0-9) and related keys (#, *), and other keys used for operating the external computing device 800 and may include a full set of alphabetic keys or set of keys that may be activated to provide a full set of alphanumeric keys. In addition to providing input, the user input interface can be used, for example, to activate or deactivate certain functions, such as screen savers and/or sleep modes. [0210] The external computing device 800 can also include volatile storage or memory 804 and/or non-volatile storage or memory 803, which can be embedded and/or may be removable. For example, the non-volatile memory may be ROM, PROM, EPROM, EEPROM, flash memory, MMCs, SD memory' cards, Memory Sticks, CBRAM, PRAM, FeRAM, NVRAM, MRAM, RRAM, SONOS, FJG RAM, Millipede memory, racetrack memory', and/or the like. The volatile memory’ may be RAM, DRAM, SRAM, FPM DRAM, EDO DRAM, SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, TTRAM, T-RAM, Z-RAM, RIMM, DIMM, SIMM, VRAM, cache memory, register memory, and/or the like. The volatile and non-volatile storage or memory' can store databases, database instances, database management systems, data, applications, programs, program modules, scripts, source code, object code, byte code, compiled code, interpreted code, machine code, executable instructions, and/or the like to implement the functions of the external computing device 800. As indicated, this may include a user application that is resident on the entity' or accessible through a browser or other user interface for communicating with the computing entity 700 and/or various other computing entities.

[0211] In another embodiment, the external computing device 800 may include one or more components or functionality that are the same or similar to those of the computing device 700, as described in greater detail above. As will be recognized, these architectures and descriptions are provided for exemplary purposes only and are not limiting to the various embodiments.

[0212] In some embodiments, the external computing device 800 can comprise the computing device 700, the computing device 700 being suitable to carry out movement of the various components of the external computing device 800, flow rates or deposition/dispersal volumes, or the like. In some embodiments, the computing device 700 or a component thereof can be configured to be in communication with the external computing device 800, which can be configured to provide instructions for printing, a design file for a printed article, printing nozzle and/or nebulizer path instructions, or the like to the computing device 700, which is configured to carry out printing.

[0213] Refernng now to FIG. 12, a method 900 for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in composite inks is illustrated. The method 900 can comprise: causing a printing nozzle to move along a predefined pathway through a yield-stress support material, at 901. The method 900 can further comprise: while causing the print nozzle to move along the predefined pathway through the yield-stress support material, communicating a printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material to form an intermediate structured article, at 902. The method 900 can further comprise: exposing the intermediate structured article in the yield-stress support material to an external field, thereby causing at least partial alignment of the printing material in the intermediate structured article in an alignment direction, at 903. The method 900 can further comprise: at least partially curing the intermediate structured article in the yield-stress support material to form a finished structured article, at 904.

[0214] Some or all of the method 900 can be carried out by an apparatus such as 100 or 200 or a computing device, such as 700 or 800. For example, an apparatus can comprise at least one processor and at least one memory storing instructions thereon that, when executed by the at least one processor, cause the apparatus to perform some or all of the method 900. Additionally, a computer program product can be provided that comprises a non-transitory computer readable storage medium storing instructions thereon that, when executed by a processor, cause a machine or apparatus to perform some or all of the method 900.

[0215] Referring now to FIG. 13, a method 1000 for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in composite inks is illustrated. The method 1000 can comprise: communicating a printing ink through a printing nozzle and into a yield-stress support material while moving the nozzle along a predefined pathway through the yield-stress support material to form an intermediate structured article, wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material, at 1001. The method 1000 can further comprise: after communicating the printing ink into the yield-stress support material to form the intermediate structured article, exposing the intermediate structured article in the yield-stress support material to an electromagnetic field or an electrical field, thereby inducing a second alignment direction to be formed in the intermediate structured article, the second alignment direction being different than the first alignment direction, at 1002. The method 1000 can further comprise: exposing the intermediate structured article in the yield-stress support material to heat, a curing agent, or a curing light, thereby at least partially curing the printing ink in the intermediate structured article, at 1003. [0216] Some or all of the method 1000 can be carried out by an apparatus such as 100 or 200 or a computing device, such as 700 or 800. For example, an apparatus can comprise at least one processor and at least one memory storing instructions thereon that, when executed by the at least one processor, cause the apparatus to perform some or all of the method 1000. Additionally, a computer program product can be provided that comprises a non-transitory computer readable storage medium storing instructions thereon that, when executed by a processor, cause a machine or apparatus to perform some or all of the method 1000.

[0217] Referring now to FIG. 14, a method 1100 for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in composite inks is illustrated. The method 1100 can comprise: causing a print nozzle to move along a predefined pathway through a yield-stress support material, at 1101. The method 1100 can further comprise: while causing the print nozzle to move along the predefined pathway through the yield-stress support material, communicating a printing ink into the yield-stress support material at a plurality⁷ of points along the predefined pathway through the yield-stress support material to form an intermediate structured article, wherein the printing nozzle is configured to exert shear forces on the printing ink, thereby causing at least partial alignment of the printing material in a first alignment direction before forming the intermediate structured article in the yield-stress support material, at 1102. The method 1100 can further comprise: exposing the intermediate structured article in the yield-stress support material to an electromagnetic field or an electrical field, thereby causing at least partial alignment of the printing material in the intermediate structured article in a second alignment direction, at 1103. The method 1100 can further comprise: at least partially curing the intermediate structured article in the yield-stress support material to form a finished structured article, at 1104.

[0218] Some or all of the method 1100 can be carried out by an apparatus such as 100 or 200 or a computing device, such as 700 or 800. For example, an apparatus can comprise at least one processor and at least one memory⁷ storing instructions thereon that, when executed by the at least one processor, cause the apparatus to perform some or all of the method 1100. Additionally, a computer program product can be provided that comprises a non-transitory computer readable storage medium storing instructions thereon that, when executed by a processor, cause a machine or apparatus to perform some or all of the method 1100.

[0219] Referring now to FIG. 15, a method 1200 for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in composite inks is illustrated. The method 1200 can comprise: printing one or more volumes of a printing ink into a yield-stress support material to form an intermediate article, the printing ink comprising a curable material and a plurality of externally alignable particles, the yield-stress support material being configured to retain the one or more volumes of the printing ink in place within the yield-stress support material as the intermediate article during a period of time after the printing and before curing the curable material, at 1201. The method 1200 can further comprise: communicating an external field towards at least a portion of the intermediate article, thereby causing at least partial alignment of at least a portion of the plurality of externally alignable particles in the printing ink in the intermediate article according to one or more alignment directions to form an aligned intermediate article, at 1202. The method 1200 can further comprise: at least partially curing the aligned intermediate article in the yield-stress support material to form a finished article, at 1203.

[0220] Some or all of the method 1200 can be carried out by an apparatus such as 100 or 200 or a computing device, such as 700 or 800. For example, an apparatus can comprise at least one processor and at least one memory’ storing instructions thereon that, when executed by the at least one processor, cause the apparatus to perform some or all of the method 1200. Additionally, a computer program product can be provided that comprises a non-transitory computer readable storage medium storing instructions thereon that, when executed by a processor, cause a machine or apparatus to perform some or all of the method 1200.

[0221] Refernng now to FIG. 16, a method 1300 for yield-stress support bath-enabled sequential dual-alignment of 2D platelets in composite inks is illustrated. The method 1300 can comprise: printing one or more volumes of a printing ink into a yield-stress support material to form an intermediate article, the printing ink comprising a curable material and a plurality' of magnetically alignable particles suspended/dispersed within at least a portion of the curable material, the yield-stress support material being configured to retain the one or more volumes of the printing ink in place within the yield-stress support material as the intermediate article during a period of time after the printing and before curing the curable material, at 1301. The method 1300 can further comprise: communicating an external magnetic field towards at least a portion of the intermediate article, thereby causing at least partial alignment of at least a portion of the plurality of magnetically’ alignable particles in the printing ink in the intermediate article according to one or more alignment directions to form an aligned intermediate article, at 1302. The method 1300 can further comprise: at least partially curing the curable material in the aligned intermediate article in the yield-stress support material to form a finished article, at 1303. The method 1300 can, optionally, further comprise: causing a print nozzle to move along a predefined pathway through the yield-stress support material, at 1304, during said printing 1301. In some embodiments, said printing 1301 the one or more volumes of the printing ink into the yield-stress support material to form the intermediate article is carried out using the print nozzle by communicating the one or more volumes of the printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material, at 1305.

[0222] Some or all of the method 1300 can be carried out by an apparatus such as 100 or 200 or a computing device, such as 700 or 800. For example, an apparatus can comprise at least one processor and at least one memory storing instructions thereon that, when executed by the at least one processor, cause the apparatus to perform some or all of the method 1300. Additionally, a computer program product can be provided that comprises a non-transitory computer readable storage medium storing instructions thereon that, when executed by a processor, cause a machine or apparatus to perform some or all of the method 1300.

[0223] Referring now to FIGs. 17-19, scanning electron microscope (SEM) images are provided that illustrate the effects of single alignment under either extrusion-induced shear force or rotating-magnetic-field-induced force couple. In particular, FIG. 17 is an SEM image of a mhBN control sample. FIG. 18 is an SEM image of cross-sectional morphology of mhBN aligned in a sample printed with relatively small extrusion-induced shear force conditions. The inset schematic in FIG. 18 illustrates the mhBN orientation state. FIG. 19 is an SEM image of cross-sectional morphology⁷ of mhBN aligned in a sample printed with relatively large extrusion-induced shear force conditions. The inset schematic illustrates the mhBN orientation state. The scale bar in each of FIGs. 17-19 illustrates scale relative to 2 pm.

[0224] As a control, FIG. 17 provides a SEM image showing randomly distributed mhBN platelets (40 wt.%, if not specified) within the epoxy matrix when no shear force or force couple is applied. Under the extrusion-printing-induced shear force, there is an alignment effect on the mhBN platelets, and this effect is more pronounced when the shear force increases, as observed in FIGs. 18 and 19.

[0225] FIG. 20 is a graph illustrating thermal conductivity versus shear force conditions, with * representing a p < 0.05, ** representing a p < 0.01, and *** representing a p < 0.001, according to some embodiments of the present disclosure. For all sample groups. n=5. [0226] Generally, a smaller dispensing nozzle diameter introduces a larger shear force. The overall alignment of the mhBN platelets is along the printing direction as seen from the increased number of the mhBN platelet edges. As a result, the thermal conductivity (in the inplane direction or the alignment direction, if not specified) and thermal enhancement factor (TEF) of the extruded samples increase under the different extrusion-induced shear force conditions as 1.2 Wm ¹ K 1.3 Wm ¹ K '. and 1.4 Wm ¹ K ¹ for thermal conductivity (control, small shear force estimated as 3.84 x 10 N, and large shear force estimated as 3.05 x 10 ^s N and 0%, 8%, and 17% for TEF of, respectively, the control, small, and large shear forces, as shown in the graph of FIG. 20.

[0227] It is noted that while a much smaller nozzle diameter introduces a larger shear force for better alignment, it may form an undesirable polymeric shell layer, which should be avoided. The formation of the polymer shell layer can be explained by the cross-stream migration of platelets in microchannels that is influenced by the channel diameter. As such, the selection of nozzle diameter should be a compromised decision.

[0228] FIG. 21 is an SEM image of cross-sectional morphology of mhBN aligned in a cast sample printed with a static magnetic field applied, according to an embodiment of the present disclosure. The inset schematic in FIG. 21 illustrates the mhBN orientation state.

[0229] FIG. 22 is an SEM image of cross-sectional morphology of mhBN aligned in a cast sample with a rotating magnetic field applied, according to an embodiment of the present disclosure. The inset schematic in FIG. 22 illustrates the mhBN orientation state. The scale bar in each of FIGs. 21 and 22 illustrates scale relative to 2 pm.

[0230] FIG. 23 is a graph illustrating respective thermal performance relative to magnetic field applied for the samples illustrated in FIGs. 21 and 22, with * representing ap < 0.05, ** representing p < 0.01, and *** representing a p < 0.001. according to embodiments of the present disclosure. For all sample groups, n=5.

[0231] Under the magnetic-field-induced force couple, the mhBN platelets are only aligned along the y direction under the SMF condition, as shown in FIG. 21. Similarly as achieved by the extrusion-induced shear force, resulting in more visible mhBN platelet edges instead of planes. In comparison, they are aligned in the x-y plane in the SEM image of FIG. 22 that is swept by the RMF. As a result, the thermal conductivity and TEF of the processed samples increase under the different magnetic field conditions as 1.2 Wm ¹ K 2.1 Wm ¹ K and 2.6 Wm ¹ K ¹ for thermal conductivity of, respectively, the control, SMF, and RMF samples, and 75% and 117% for TEF, respectively, under the SMF and RMF conditions, as shown in the graph of FIG. 23. It is noted that RMF only works better for planar alignment if the matrix is fluidic or less viscous.

[0232] As seen from FIGs. 4A-4D, the shear force makes the mhBN platelets directionally aligned along the printing direction (FIG. 4B), and the RMF -induced force couple arranges them planarly (FIG. 4C). Intuitively, it is favored to combine both the extrusion-induced force and RMF-induced force couple alignment approaches for better complementary alignment performance.

[0233] However, it was not feasible until the recent advance in liquid-in-liquid embedded printing in a yield-stress bath. The mhBN composite structure is still liquid after being printed, which enables the following alignment step using RMF as a sequential dual-alignment process. As such, the overall alignment performance is expected to be the summation of both alignment effects.

[0234] FIGs. 24 and 25 illustrate the alignment results under the dual-alignment approach. In particular. FIG. 24 is an SEM image of cross-sectional morphology of mhBN aligned in a sample printed with relatively small extrusion-induced shear force conditions and with a rotating magnetic field applied, according to an embodiment of the present disclosure. The inset schematic in FIG. 24 illustrates the mhBN orientation state. FIG. 25 is an SEM image of cross-sectional morphology of mhBN aligned in a sample printed with relatively large extrusion-induced shear force conditions and with a rotating magnetic field applied, according to an embodiment of the present disclosure. The inset schematic in FIG. 25 illustrates the mhBN orientation state. The scale bar in both of FIGs. 24 and 25 illustrates scale relative to 2 pm.

[0235] As seen from FIGs. 24 and 25, the mhBN platelets are aligned in the x-y plane under two different combinations, small shear force/RMF and large shear force/RMF, respectively. Both show fewer platelet “faces” and more horizontally aligned platelet “edges,” meaning that better planar alignment results are achieved using the dual-alignment approach when compared with those using the individual extrusion-induced alignment, as illustrated in FIG. 19, and RMF approach only, as illustrated in FIG. 22.

[0236] To verily the planar alignment under the dual-alignment condition, X-ray diffraction (XRD) analysis was performed for the samples that were randomly aligned and planarly aligned by the dual-alignment method, and the results are shown in FIG. 26. In particular, FIG. 26 provides a graph illustrating the results of the XRD analysis of 20 wt.% mhBN/epoxy composite samples under different observation directions, including dually- aligned samples observed parallelly and perpendicularly to the printing direction, according to some embodiments of the present disclosure. For all sample groups, n=5.

[0237] Two evident peaks at 26.8° and 41.6° are observable, corresponding to the (002) and (100) planes, respectively, indicating the horizontal and vertical orientations of the mhBN platelets. 20 wt.% mhBN samples were selected to determine the relative intensity (I100/I002) of the platelets after the dual alignments. When the alignment plane of the samples is parallel to the direction of the incident X-ray beam, the relative intensity⁷ is 5.29, while for samples with the alignment plane perpendicular to the X-ray beam, the relative intensity is 0.02. By contrast, the relative intensity⁷ for the nonaligned samples (control) is 0.17, demonstrating that the sequential dual-alignment method introduces significant planar alignment.

[0238] As expected, the thermal conductivity of the aligned samples increases from 1.2 Wm ¹ K ¹ (control) to 4.3 Wm ¹ K ¹ (dual alignment with small shear force and RMF) or 9.5 Wm ¹ K ¹ (dual alignment with large shear force and RMF). respectively, for the 40 wt.% sample after the sequential dual-alignment process. The resulting increase in thermal conductivity is 3.1 Wm ¹ I< ¹ and 8.3 Wm ¹ K '. respectively. For comparison, the thermal conductivity increases of the simple cumulative effect of shear force (small and large) and RMF force couple alignments are 3.9 Wm ¹ K ¹ and 4.0 Wm ¹ K respectively. The comparison of these values shows a pronounced synergistic effect in improving the thermal conductivity as 2.7 Wm ¹ K ¹ (blue arrow) versus 3.1 Wm ¹ K ¹ (simple summation of small shear force and RMF effects vs sequential dual-alignment effect), and 2.8 (blue arro v) versus 8.3 Wm ¹ K ¹ (simple summation of individual large shear force and RMF effects vs sequential dualalignment effect). The latter one exemplifies a 2.4-times increase in the thermal conductivity value by adopting the sequential dual-alignment method instead of simply adding the effects from both alignments.

[0239] This much-expected synergistic effect is attributed to the partial alignment of 2D platelets by the initial extrusion-induced directional shear force, which facilitates the axial rotation of the platelets for better planar alignment under the RMF-induced force-couple- induced torque. Without extrusion-induced pre-alignment, the mhBN platelets are randomly distributed, and this randomness of platelet arrangement requires a higher subsequent net torque and/or a longer time for planar alignment, which may introduce some challenges in aligning 2D platelets in viscous matrixes. By adopting the sequential dual-alignment method, the mhBN platelets are aligned by the extrusion-induced shear force, which rotates the axes of the platelets parallel to each other and along the filament extmsion direction. With this prealignment, the subsequent RMF can planarly align the platelets more efficiently, requiring a lower torque and/or a shorter time.

[0240] The main advantage of the sequential dual-alignment strategy is that it pre-aligns the platelets to reduce the initial arrangement randomness that facilitates the subsequent RMF alignment and efficiently aligns the platelets more planarly.

[0241] The significance of the observed synergistic effect is dependent on the mhBN concentration. At low concentrations, the synergistic effect is not as pronounced since the platelets at low concentrations find it hard to form effective thermal conductive pathways even when the mhBN platelets are perfectly planarly aligned. As such, the thermal resistance of the polymeric matrix among the adjacent or nearby platelets is still large, meaning that the dualalignment approach does not outperform the sum of the individual alignment methods at low mhBN concentrations even though it outperforms the alignment methods individually.

[0242] With the increase of the mhBN concentration, the synergistic effect becomes evident, as seen from FIG. 27. When the mhBN concentration is 20 wt.%, the thermal conductivity improvement due to the synergistic effect is 0.1 Wm ¹ K '. meaning the dual alignments show a synergistic effect and outperform the sum of individual alignment methods. When the mhBN concentration is 40 wt.%. the synergistic effect is more pronounced as aforementioned. Its thermal conductivity improvement due to the synergistic effect increases to 5.5 Wm ¹ K '. and the effective alignment results can be reflected in the thermal conductivity measurement. In addition, the degree of composite heterogeneity is evaluated as a function of alignment methods and mhBN concentration based on the XRD-measurement- data-derived relative intensity (I100/I002). High heterogeneity and better planar alignment are achieved using any alignment, while the sequential dual-alignment approach is more effective for reducing the homogeneity than any single-alignment method. The relative intensitydecreases with the mhBN concentration, meaning a lower degree of heterogeneity at higher concentrations.

[0243] In terms of the TEF value under the large shear force and RMF effects, it increases from 17% (large shear force only) and 117% (RMF only) to 692% (dual alignments), a more than 5 times increase. [0244] FIG. 28 further shows the thermal conductivity and TEF as functions of the mhBN concentration. The thermal conductivity always increases with the mhBN concentration while TEF increases to a maximum value at 743% at 30 wt.% and decreases to 692% and 557% at 40 wt.% and 50 wt.%, respectively. The TEF trend (first increase and then decrease at high mhBN concentrations) is attributed to the interference among crowded mhBN platelets, which hinders the free rotating of mhBN platelets under RMF.

[0245] Since the thermal conductivity always increases, the TEF value may not be of concern if it is not of application interest. The dual-alignment performance of mhBN is further compared to those in open literature in terms of thermal conductivity and TEF, as illustrated in FIG. 29. For fair comparisons, studies using different platelet fillers such as boron nitride nanosheets (BNNS) and different matrix polymers such as thermoplastic polyurethane are excluded since the focus of this study is on the performance improvement resulting from the dual-alignment approach rather than the improvement arising from the use of some specific materials. As such, only studies that utilized the same platelet filler (hBN) and matrix material (epoxy) are considered. To benchmark the comparability of the measurement results from this study, the thermal conductivity of the mhBN and epoxy composite under single alignment approaches are first compared with published results using the same or similar materials.

[0246] According to some examples provided herein, the thermal conductivity of the 40 wt.% mhBN composite is 1.4 Wm ¹ K ¹ and 2.1

respectively, corresponding to the individual large shear force alignment and SMF alignment conditions. The values are consistent with those from open literature, which are from 0.8 Wm ¹ K ¹ to 2.8 Wm ¹ K ¹ under the extrusion-induced single shear force alignment approach or from 0.8 Wm ¹ K ¹ to 2.9 Wm ¹ K ¹ under the SMF alignment approach as the alignment approach for the same or similar materials, showing that the measurement results are trustworthy. It is noted that no RMF-based work is identified, so it is not compared with that of this study.

[0247] As aforementioned, the thermal conductivity increases with the mhBN concentration. With a mhBN concentration of 50 wt.%, a thermal conductivity value of 13.8 Wm ¹ K ¹ can be achieved with the assistance of the dual-alignment approach. For 30 wt.% BN, 40 wt.% BN, and 50 wt.% BN composites, the resulting thermal conductivity values (5.9 Wm ¹ K '. 9.5 Wm ¹ K '. 13.8 Wm ¹ K ') show a notable improvement when compared to the previously reported highest values using single shear-force-induced alignment (that happened to be a hot pressing process), which are 5.3 Wm ¹ K '. 6.6 Wm ¹ K and 8.6 Wm ¹ K an improvement of 11%. 44%, and 60%, respectively. As seen in FIG. 29, the sequential dual-alignment approach outperforms not only the single extrusion-induced shear force alignment or SMF-induced force couple alignment processes, but also other methods such as hot pressing, surface treatment, freeze casting, and gravity-assisted alignment for the same or similar materials. Herein, the thermal conductivity was evaluated based on the platelet in-plane direction. For comparison, the through-plane thermal conductivity was also characterized, and it is found that the sequential dual-alignment approach reduces the through- plane thermal conductivity by almost half (from 0.5 W m ¹ K ¹ for no-alignment composites to 0.3 Wm ¹ K ¹ for dual-alignment composites) while the extrusion alignment changes its value to 0.6 W m ¹ K ¹ in each direction since some mhBN platelets are aligned axially (equal probability to have almost similar numbers of in-plane and through-plane platelets at any given measurement position) and the rotating magnetic field alignment decreases it to 0.4 W m ¹ K ¹. [0248] Illustrated and described herein is the feasibility of the proposed sequential dualalignment approach and the significance of its synergistic alignment effect. Exploring the thermal conductivity enhancement resulting from the physical properties of other advanced materials such as BNNS, thermoplastic polyurethane (as matrix material), and FeCh • 6H2O (for magnetic surface coating) is a focus of future implementation studies, and significantly improved thermal conductivity is expected.

[0249] Among other advantages, one advantage of using boron nitride in dielectric materials is that it not only enhances thermal conductivity but also maintains good electrical insulation properties. The effect of boron nitride orientation on the dielectric properties of composite materials was investigated in terms of the dielectric constant and dissipation factor. It was found that the proposed sequential dual-alignment approach helps achieve the improved in-plane alignment of mhBN, leading to a smaller dielectric constant. At the same time, the dissipation factor or dielectric loss of the composite sample after dual alignments maintains at very low level, which is comparable to that of those after no alignment and single alignment.

[0250] The effectiveness of the sequential dual-alignment process is further analyzed in terms of the effects of the dispensing nozzle geometry, RMF rotational frequency, and composite ink viscosity, which is coupled with the two individual alignment processes, during extrusion-induced force and RMF-induced force-couple-induced alignments, respectively. For simplicity, it is assumed that the mhBN/epoxy composite ink can be represented using a powerlaw function (r/ = Ky" ' where 77 is the ink viscosity, y is the shear rate, K is the flow consistency index, and n is the power-law index) and its dispensing flow is a Hagen-Poiseulle flow modeled with a power-law function.

[0251] The viscosity versus shear rate property of the composite ink with different mhBN concentrations as well as the resulting linear regression model are plotted in the graph of FIG. 30, and the K and n values under each mhBN concentration condition are plotted in the graph of FIG. 31. Since the Reynolds number is estimated on the order of I O ¹, the ink flow is safely considered laminar.

[0252] Selected of the mechanical properties and characteristics that were considered/analyzed for one or more of the composite ink, yield-stress support bath material, intermediate printed article, finished article, and/or other compositions of matter disclosed herein are provided below in Table 1.

Table 1. Examples of Material Characteristics and Mechanical Properties Analyzed

[0253] During the extrusion-induced force alignment process, the shear stress is maximal along the wall of the dispensing nozzle and decreases linearly toward the center of the nozzle according to the shear stress distribution profile in the dispensing nozzle that can be simplified as follows:

[0255] where Twaii is the shear stress applied by the internal wall of the dispensing nozzle, A ? is the pressure drop along the dispensing nozzle that is inversely proportional to the nozzle diameter, based on the Hagen-Poiseulle flow with a power-law function, r is the radial distance from the center of the nozzle, and I is the length of the dispensing nozzle. [0256] FIG. 32 shows the extrusion-induced maximum shear stress when using different dispensing nozzles. As the nozzle diameter decreases, the resultant shear force increases, leading to a higher thermal conductivity and a higher TEF as discussed before. Since the dispensing nozzle-induced shear force can only align 2D platelets in the printing direction, 2D platelets have one more degree of freedom in the rotating direction, which cannot be effectively aligned with this single alignment approach. Consequently, the extrusion-induced shear force alignment on the thermal conductivity improvement is limited as reported by other studies whose thermal conductivity value usually falls within the range of from 0.8 W m ¹ K ¹ to 2.8 W m ¹ K ¹ at the BN concentration of 40 wt.%.

[0257] Dunng the RMF-induced force couple alignment process, the alignment is performed alternatively and repeatedly in every direction in the x-y plane by the rotating field. The mhBN alignment dynamics under a magnetic field can be analyzed by studying the torque applied by the external magnetic field on a single mhBN platelet, as shown in FIG. 33. Since the gravitational torque is negligible, the net torque T on a single platelet is the sum of the magnetic (T_m) and viscous (7^) torques as T = T_m + T . Herein, the magnetic torque T_m can be determined as follows:

[0259] where fio denotes the magnetic permeability of free space. %_ps is the magnetic susceptibility of the particle shell, a is half the thickness of the mhBN platelet, b is half the diameter of the mhBN platelet, d is the diameter of the coating ferromagnetic nanoparticles, Ho is the external magnetic field strength, and is the orientation of the mhBN platelet with reference to the plane generated by the RMF. Under the given mhBN platelet filler, matrix, and magnetic field conditions, the magnetic torque working on each mhBN platelet depends on the orientation of the platelet d. as show n in FIG. 34.

[0260] While the platelets rotate due to the effect of the magnetic force couple, the viscous torque 7'_P drags the platelet in the opposite direction, which is illustrated in FIG. 34 and can be calculated as follows:

[0262] where V_P is the volume of mhBN platelets,

is the angular frequency of the f rolling of mhBN platelets, — represents the Perrin friction factor. fo [0263] By solving Equations (2) and (3) in T = T_m + T> simultaneously,

can be solved,

and consequently

can be represented as a function of ^and r/.

[0264] FIG. 35 shows the net torque T on a single platelet when the composite viscosity is 182 Pa s for the 40 wt.% mhBN/epoxy composite ink. The magnetic, viscous, and net torques may be functions of the ink viscosity, magnetic field strength, and platelet orientation.

[0265] While the ink viscosity does not significantly impact the magnetic torque, the viscous torque is sensitive to the ink viscosity, resulting in a noticeable net torque shift. An increase in the ink viscosity from 0.01 Pa s to 100.00 Pa s may result in a decrease in net torque on the order from 10 ¹⁴ Nm to I O ²⁴ Nm. The magnetic field strength also directly influences the magnetic torque and the corresponding viscous torque; when the magnetic field strength changes from 0.01 T to 1.50 T, it may cause the net torque to increase on the order from I 0 ²⁸ Nm to 10 ¹⁴ Nm. These modeling results are consistent with those from previous studies in terms of their magnitudes, confirming their validity' and reliability.

[0266] Though the composite ink viscosity -/changes gradually due to the cross-linking of the polymer, for comparison purposes, the time needed for a platelet to be planarly aligned is estimated using the initial ink viscosity per the following equation:

[0268] This is the minimum time since the cross-linking process makes the ink more viscous over time, which may increase the required alignment time. It is noted that the ink viscosity is influenced by the mhBN concentration as well as the cross-linking process of the polymer matrix. Generally, the mhBN concentration is increased to improve the thermal conductivity of the composite, which directly increases the ink viscosity, as shown in FIG. 30. The composite matrix in this study is epoxy, which cross-links once the composite ink is premixed. As a result, the viscosity increases as printing time goes by. The time needed for a platelet to be fully aligned with the RMF sweeping plane can be roughly approximated as a function of viscosity using Equation (4). Herein, the composite ink 10 min after being prepared has the lowest viscosity of 182 Pa s at the shear rate of 0.1 s ¹ while it is 692 Pa s after 90 min, as shown in FIG. 36. The composite ink shows a shear-thinning property.

[0269] Per Equation (4), the alignment time for inks that are printed 10 min or 90 min after preparation is 7.73 s and 29.40 s, respectively, as shown in FIG. 37. It should be noted that during the alignment of mhBN platelets, the ink continues to cross-link and increase in viscosity, actually requiring more time than the estimated value for alignment. Therefore, the ink concentration and ink post-mixing time adopted herein are reasonable, which allows mhBN platelets to be fully aligned before the polymer matrix is too viscous.

[0270] Careful selection of the RMF rotational frequency is essential to achieve effective alignment. At sufficiently low frequencies of the magnetic field rotation, mhBN platelets are primarily influenced by magnetic torque and exhibit synchronous rolling along the substrate surface, known as phase-lock. To prevent phase-lock phenomena, the external magnetic field rotation must surpass a critical frequency, which can be determined as follows to achieve planar alignment:

[0272] The critical frequency for the mhBN/epoxy composite inks with different concentrations of 10 Pa s - 1,000 Pa s is then determined between about 0. 16 rad s ¹ and about

16.07 rad s '. For this study, it was kept at about 235 rpm (24.61 rad s ') for the various inks under the given RMF strength.

[0273] For its exceptional electrical insulating and thermal conductive properties, the mhBN/epoxy composite ink can be a promising material for thermal management in electronic devices.

[0274] The mhBN/epoxy composite ink described herein can comprise hBN that is modified to be magnetic force-responsive by coating a layer of magnetic-field-responsive materials, such as iron oxide (FesO-i) nanoparticles, on the surface of hBN platelets to form magnetic hBN (mhBN). The various compositions of mhBN/epoxy composite ink evaluated were validated compositionally with elemental analysis. An example of the elemental constitution of the mhBN/epoxy composite ink is provided below in Table 2.

Table 2. Elemental Constitution of an example mhBN/epoxy composite ink.

[0275] Referring now to FIGs. 38A-38C, the mhBN platelets are illustrated in a mhBN/DI water dispersion. FIG. 38A is an image of an initial mhBN dispersion in DI water in a beaker after complete and continuous mixing and shaking of the mixture. FIG. 38B is an image of the mhBN sediment having settled to the bottom of the beaker bottom over time in the absence of an external magnetic field. FIG. 38C, alternatively, is an image of the beaker when a magnet is placed vertically along the beaker and demonstrates the magnetic field responsivity of the prepared mhBN platelets by showing their accumulation along the wall next to the magnet placed vertically along the beaker.

[0276] Furthermore, the presence of FesC nanoparticles on the surface of hBN platelets was characterized using transmission electron microscopy (TEM). FIG. 39 is a bright-held TEM image of mhBN platelets, and the FesCh nanoparticles can be clearly observed. To further examine the composition of the presented particles, the energy⁷ dispersive X-ray spectroscopy in scanning transmission electron microscopy (STEM-EDS) was utilized, and the EDS mapping further shows the presence of Fe and O elements in addition to B and N. as illustrated in FIGs. 40-44.

[0277] Referring now to FIGs. 45-50, the morphology⁷ of fabricated mhBN/epoxy composite samples was observed by scanning electron microscopy (SEM), resulting in the illustrated SEM images and energy dispersive spectroscopy (EDS) mapping of the mhBN/epoxy composite samples. The mhBN platelets are homogeneously distributed in the epoxy polymer, FIG. 45 shows the selected area for EDS analysis, and FIGs. 46-50 show the elements detected in the mhBN/epoxy composite samples.

[0278] Specifically, the elemental composition of a filament printed using 20 wt.% mhBN under RMF was determined by EDS as show n in Table 1. To have a better view of the elements distributed along the in-plane direction of aligned mhBN platelets, a surface area along the lateral direction of the filament was selected as shown in FIG. 45. The distribution of overall and individual elements in this selected area is shown in the elemental mapping in FIGs. 46- 50. which further confirms the uniform distribution of all elements and no significant mhBN aggregates are found in the specimens. It indicates that the mhBN platelets are homogeneously dispersed in the epoxy matrix. The constitution of the mhBN/epoxy analyzed by EDS is listed in Table 1, which shows the presence of 1.8 wt.% of iron and further proves that FesCfi is coated on the BN platelets successfully.

[0279] Referring now to FIGs. 51A-51B, an example printing configuration as well as dual-alignment setup are shown. FIG. 51 A shows that the printing configuration comprises a platform supporting a print bath container having stored therein a support bath material. A printhead is positioned above the print back container and has a syringe mounted thereon with a nozzle affixed at a distal end of the syringe. The syringe is configured to communicate printing ink from a reservoir, through the nozzle, and into the support bath material retained within the print bath container. The printhead is configured to move the syringe and nozzle in a variety of directions, including vertically, horizontally, diagonally, and/or rotationally.

[0280] FIG. 5 IB illustrates the dual-alignment setup that can be added to the printing configuration in FIG. 51 A or replace components thereof. The dual-alignment setup can include a rotating stage supported on the platform that supports thereon the print bath container. The rotating stage can be coupled to a motor configured to cause rotation of the rotating stage about a particular rotation point, such as a middle point of the rotating stage. The rotating stage can include one or more magnets supported or mounted thereon, or integrated therein. The rotating stage can comprise a container holder configured to retain the support bath container adjacent to a magnet or between two or more magnets. The motor can be configured to cause rotation of the rotating stage before, during, and/or after the printhead causes extrusion/printing of the printing ink from the syringe, through the nozzle, and into the support bath material in the support bath container.

[0281] The alignment effectiveness of the sequential dual-alignment approach and the resulting thermal performance enhancement are investigated when printing with the representative 40 wt.% mhBN/epoxy composite ink. Specifically, three different alignment approaches were implemented: extrusion-induced shear force alignment, magnetic field- assisted alignment, and sequential dual alignments.

[0282] If not specified, each experiment was conducted in triplicates, and the control was samples made by casting. The alignment effectiveness is characterized using SEM and X-ray diffraction (XRD), and the thermal performance enhancement is evaluated based on the thermal conductivity and thermal enhancement factor.

[0283] For the extrusion -induced shear force alignment group, samples were printed using three different shear force conditions without the magnetic field applied: no shear force (casting), a small shear force when using a large dispensing nozzle (gauge 20, ID 0.584 mm), and a large shear force with a small dispensing nozzle (gauge 23, ID 0.330 mm). The maximum shear force in the dispensing nozzles under these three conditions is estimated as, respectively, O N, 3.5 x W⁸ N, and 3.84 x 10’⁸ N.

[0284] For the magnetic field- assisted alignment approach group, samples were prepared using three different magnetic field conditions: no magnetic field, SMF, and RMF. For the SMF and RMF groups, a pair of magnets with a magnetic strength of 1.48T was employed for both cases. The effective magnetic strength at the center of the magnet couple was 0.4 T. For the RMF group, a custom-made spinning stage with an adjustable rotating speed ranging from 0 rpm to 235 rpm was utilized. The starting samples were cast using freshly prepared inks, and the magnetic field was applied to the samples during the entire solidification process until complete solidification.

[0285] For the dual-alignment approach group, the preferable conditions from each single alignment approach, namely the larger shear force and the RMF conditions, were utilized.

[0286] The thennal enhancement factor (TEF) serves as an additional indicator of the improved thermal conductivity resulting from the alignment of mhBN platelets. Two distinct approaches are commonly employed to determine the TEF. The first approach involves considering the pure polymer matrix as the reference, denoted as TEFp. The second approach involves using a composite with the same mhBN concentration but without alignment (randomly aligned) as the reference, denoted as TEFr. The TEF values under these two conditions can be calculated using the following equations:

[0288] where k refers to the thermal conductivity, and the subscript represents the different groups of the samples (aligned mhBN, polymer matrix only, and randomly distributed mhBN). [0289] Referring now to FIG. 52, the shear stress applied by the dispensing nozzle on mhBN plates can rotate mhBN platelets and align them in the extrusion direction. For a 40 wt.% mhBN ink, the maximum shear stress within a nozzle with a diameter of 330 pm (i.e. , Gauge 23) is 339 Pa, as shown in FIG. 52. Accordingly, the maximum shear force applied by the printing nozzle can be approximated.

[0290] For example, for the 330 pm nozzle, F — T X A — 339 N m~²

=

3.84 X 10^-8A.

[0291] Therefore, the extrusion-induced maximum shear force within the small nozzle is 3.84 x 10^-8lV. Similarly, the maximum shear force in a 584 pm nozzle (i.e., Gauge 20) can be estimated as 3.05 x 10“ ⁸N. [0292] Referring now to FIGs. 53-55, if the nozzle size is too small, the friction between the internal wall of the dispensing nozzle and the extruded ink may become too high. As a result, only the low-viscosity portion of the composite ink can be easily extruded out relatively, especially near the wall area, therefore a viscous epoxy-based shell may be generated around the wall area, encasing a forming filament, as shown in FIG. 53 and FIG. 54.

[0293] FIG. 55 is a graph that depicts the shell thickness and shell thickness ratio with respect to the nozzle diameter. The shell formation turns pronounced when a small nozzle is used. Since the epoxy shell functions as a barrier that hinders thermal conduction between neighboring filaments, it should be avoided.

[0294] To investigate the synergistic effect of the sequential dual -alignment approach as well as the contribution of the individual alignment method to the overall TC performance of the mhBN/epoxy composite samples, samples prepared using the following approaches were tested: under extrusion-only, RMF-only, and sequential dual-alignment approach. The mhBN concentration was also varied at the weight ratio of 10 wt.%, 20 wt.%, and 40 wt.%. To evaluate the synergistic effect, thermal performance comparison was particularly conducted for the samples that were prepared using dual alignment and each individual method.

[0295] FIG. 56 is a graph that depicts the thermal conductivity of the samples prepared using each individual alignment method as well as the sequential dual -alignment method, and the arrows represent the improvement due to the synergistic effect, which represents the difference between the thermal conductivity’ of the sample prepared using the dual alignment and the sum of that of the samples prepared using each individual alignment method:

[0297] where kDuai, Intrusion, and k uF are the thermal conductivity of samples prepared using the dual alignment, extrusion alignment, and RMF alignment, respectively, and ksynergy is the thermal conductivity improvement due to the synergistic effect.

[0298] Referring now to FIGs. 57-60, the degree of mhBN platelet heterogeneity as a function of alignment methods and mhBN concentration has been assessed using the relative intensity of (100) peak to (002) peak of XRD measurements of samples processed under different alignment conditions (no alignment, single alignment (extrusion alignment and magnetic field alignment), and dual alignments) from different mhBN concentrations. Horizontally aligned hBN platelets (platelets horizontally aligned with respect to the incident X-ray beam, which have the planar alignment of interest) are responsible for (002) peaks while the vertically aligned hBN platelets (platelets vertically aligned with respect to the incident X- ray beam) are responsible for (100) peaks.

[0299] FIG. 57 and FIG. 58 show XRD results of the 20 wt.% mhBN/epoxy composites aligned under different alignment methods, and the measurements were conducted when the processed composite samples were arranged horizontally, matching that of the printing direction or the planar alignment direction of interest. Compared with the no-alignment sample, two single alignment, and one dual-alignment samples show decreased relative intensity (I100/I002), suggesting that higher heterogeneity and better planar alignment are achieved using any alignment, while the sequential dual-alignment approach is more effective for reducing the homogeneity than any single-alignment method. This conclusion also aligns with the findings on the thermal enhancement factor, which show an increasing trend for the no-alignment, single-alignment, and dual-alignment samples.

[0300] Similarly, FIG. 59 and FIG. 60 show XRD results of the samples with various concentrations (20%, 30%, 40%, and 50%) aligned under the sequential dual-alignment method. Clearly, the intensity increases with the mhBN concentration, but the relative intensity (I100/I002) decreases with the mhBN concentration, meaning a lower degree of heterogeneity at higher concentrations.

[0301] FIG. 61 is a graph that illustrates the comparison of TEF_P and reveals a consistent and monotonic increase with the higher hBN content, regardless of the alignment method employed. This phenomenon can be attributed to the introduction of hBN platelets, which exhibit significantly higher thermal conductivity compared to that of the polymer matrix. Consequently, the inclusion of hBN platelets in the composites leads to an overall enhancement of thermal conductivity when compared to that of the pure polymer matrix, thereby resulting in an increased TEF_P.

[0302] In order to eliminate the potential confounding effects arising from varying hBN concentrations and to gain a better understanding of the thermal performance enhancement attributed solely to the alignment process, the TEFr, which is defined as the relative thermal enhancement factor (calculated by benchmarking against the non-aligned counterparts with the same hBN concentration as the baseline), is employed for comparison.

[0303] Analysis provided in FIG. 62, for example, reveals that the TEF_r no longer exhibits a monotonic response with respect to the hBN concentration, as the thermal enhancement is primarily influenced by the degree of alignment achieved for the platelets compared to those of their non-aligned counterparts with the same hBN concentration.

[0304] At lower hBN concentrations (e.g, below 20 wt.%), the TEF_r value indicates limited improvement. This is primarily due to the sparse distribution of platelets, regardless of their alignment status, which hinders the formation of effective conductive pathways. As a result, the thermal performance difference between the aligned and non-aligned groups remains relatively small. On the other hand, at higher hBN concentrations, the viscosity increase due to the inclusion of hBN platelets becomes a limiting factor for effective alignment using traditional alignment methods. In contrast, the dual-alignment mechanism demonstrates superior capability in aligning mhBN platelets. For example, the corresponding TEFr values are 760.29%, 691.67%, and 554.76%, respectively, for the mhBN concentration of 30 wt.%, 40 wt.%, and 50 wt.%.

[0305] The planar alignment of mhBN platelets in mhBN/epoxy composites presents an enhanced effect on the thermal conductivity of composites due to hBN’s outstanding in-plane thermal conductivity. For comparison, the through-plane thermal conductivity was also investigated for composites fabricated using three different alignment approaches: extrusion alignment, rotating magnetic field alignment, and sequential dual alignments. The control was the composite without any alignment.

[0306] FIG. 63 illustrates the thermal conductivity along the through-plane direction of 20 wt.% mhBN/epoxy composites fabricated using three different alignment approaches. For the composite without any alignment, the thermal conductivity values are similar (e.g., 0.5 W m’¹ K’¹) when measured along the in-plane and through-plane directions since all the mhBN platelets are oriented randomly within the composite. Under the extrusion-alignment condition, 2D platelets are aligned along the axial printing direction only. Ideally, this should result in the same number of the mhBN platelets along the in-plane and through-plane directions, however, the compression applied by the nozzle tip during printing leads to a slightly elliptically -shaped filament cross-section, promoting additional trivial alignment of the mhBN platelets in the horizontal printing direction (e.g, 0.8 W m ¹ K ¹ in-plane vs., e.g, 0.6 W m’¹ K ¹ through-plane). Consequently, the through-plane thermal conductivity is slightly lower than that along the in-plane direction. Under the magnetic field alignment condition, it allows planar alignment of mhBN, the through-plane thermal conductivity is significantly reduced compared to that along the in-plane direction (e.g, 1.1 W m’¹ K ¹ in-plane vs. e.g, 0.4 W m’¹ K’¹ through-plane). Due to its synergistic effect on planar alignment, the sequential dual-alignment approach results in a substantial decrease in the through-plane thermal conductivity (e.g, 2. 1 W m'¹ K'¹ in-plane vs. e.g., 0.3 W m’¹ K ¹ through-plane).

[0307] Referring now to FIGs. 64-68, the effect of mhBN platelet orientation on the dielectric properties of 40% mhBN/epoxy composite samples with different mhBN platelet orientations introduced by different alignment methods was evaluated in terms of the dielectric constant and dissipation factor. The mhBN platelet orientation was controlled using the noalignment, single- alignment (extrusion printing-induced shear force), and dual-alignment approaches, and the measurement directions for the samples are depicted in FIGs. 64-66. The dielectric constant, depicted in the graph of FIG. 67, of all composite samples shows consistently low values (from 5.03 to 5. 13 for the no-alignment sample, from 5.35 to 4.45 for the single-alignment sample, and from 5.86 to 4.33 for the dual-alignment sample) at the frequency range of 100 Hz to 1 MHz with a decreasing trend of the dielectric constant from the no-alignment to single-alignment to dual-alignment approaches. For example, the dielectric constant is 5.13, 4.46, and 4.33 (using the 1 MHz measurement data as an example) for the noalignment, single-alignment, and dual-alignment composite samples, respectively. This indicates that the alignment of mhBN enables the composites to have better electrical insulation properties (smaller dielectric constant). The out-of-plane dielectric constant of hBN is lower than the in-plane dielectric constant, and the dual-alignment approach disclosed herein helps achieve the improved in-plane alignment of mhBN, resulting in a smaller dielectric constant. Additionally, the dissipation factor or dielectric loss of the composite sample after dual alignments maintains a very' low level (from 0.45 to 0.023 under the frequency 100 Hz to 1 MHz), as shown in FIG. 68, which is comparable to that of those after no alignment and single alignment, indicating the good potential to be used in electronic components.

[0308] The pressure drop along the dispensing nozzle can be found based on the Hagen- Poiseuille flow with a power-law function:

[0309] Ap = —21K [Q pp) /TNT¹]” (8)

[0310] where O is the volume flow rate. R is the radius of the dispensing nozzle, and K and n are the flow consistency index and power-law index obtained through regression models from the rheological analysis of the composite inks using the following equation:

[0311] F) = Ky^71-1 (9) [0312] The printing-indued shear rate (y) of composite inks in different nozzles can be estimated using the equation:

[0314] where d is the nozzle diameter and Q is the volume flow rate that is determined based on the given printing speed (e.g., 2 mm s'¹). f

[0315] For the modeling of the magnetic field effect, — represents the Perrin friction factor, fo which is previously derived as:

[0319] where p is the aspect ratio of the platelet. The

is the angular frequency of the

rolling of mhBN platelet, which can be determined as follows:

[0321] where rris the angular acceleration, the moment of inertia I can be calculated using the weight and diameter of a single platelet.

[0322] FIG. 69 and FIG. 70 show the magnetic and viscous torque responses to different ink viscosities and magnetic field strengths, and FIG. 71 and FIG. 72 show the net torque responses to different ink viscosities and magnetic field strengths.

[0323] The influence of FesCU nanoparticles on the thermal conductivity of the hBN composite was investigated through a comparative study of the thermal conductivity of the 30 wt.% hBN and 30 wt.% mhBN samples. As depicted in FIG. 73, the addition of hBN and mhBN results in an increase in the thermal conductivity' from 0.2 W m'¹ K'¹ to 0.9 W m'¹ K'¹ and 0.7 W m^ K ¹. respectively, when compared to that of the pure epoxy matrix. Since the introduction of nanoparticles as a surface coating on hBN inhibits thermal conduction, the mhBN sample exhibits a reduced thermal conductivity from 0.9 W m'¹ K'¹ to 0.7 W m'¹ K'¹ when compared to that of the hBN/epoxy sample.

[0324] Despite the hindrance to the thermal conduction posed by the Fes Ch nanoparticles, their inclusion enables the responsiveness of the mhBN platelets to an external magnetic field, facilitating an effective dual-alignment approach to be utilized. The dual -alignment method results in a notable enhancement in the thermal conductivity', reaching 5.9 W m'¹ K'¹ in the mhBN sample. Thus, the use of FesC nanoparticles enables the dual-alignment approach and ultimately yields a significantly improved thermal conduction performance of the mhBN/ epoxy composite, overshadowing the thermal insulation effect introduced by the Fe^Ch nanoparticles. Conclusion

[0325] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, the combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning consistent with the particular concepts disclosed herein.

[0326] In some embodiments, one or more of the operations, steps, elements, or processes described herein may be modified or further amplified as described below. Moreover, in some embodiments, additional optional operations may also be included. It should be appreciated that each of the modifications, optional additions, and/or amplifications described herein may be included with the operations previously described herein, either alone or in combination, with any others from among the features described herein.

[0327] The provided method description, illustrations, and process flow diagrams are provided merely as illustrative examples and are not intended to require or imply that the steps of the various embodiments must each or all be performed and/or should be performed in the order presented or described. As will be appreciated by one of skill in the art, the order of steps in some or all of the embodiments described may be performed in any order. Words such as “thereafter,” “then.” “next.” etc. are not intended to limit the order of the steps; these words are simply used to guide the reader through the description of the methods. Further, any reference to claim elements in the singular, for example, using the articles “a,” “an,” or “the” is not to be construed as limiting the element to the singular. Further, any reference to dispensing, disposing, depositing, dispersing, conveying, injecting, inserting, communicating, and other such terms of art are not to be construed as limiting the element to any particular means or method or apparatus or system, and is taken to mean conveying the material within the receiving vessel, solution, conduit, or the like by way of any suitable method. [0328] Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of teachings presented in the foregoing descriptions and the associated drawings. Although the figures only show certain components of the apparatus and systems described herein, it is understood that various other components may be used in conjunction with the system. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, the steps in the method described above may not necessarily occur in the order depicted in the accompanying diagrams, and in some cases one or more of the steps depicted may occur substantially simultaneously, or additional steps may be involved. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Specific equipment and materials described in the examples are for illustration only and not for purposes of limitation. For instance, any and all articles, portions of articles, structures, bulk materials, and/or the like, having any form factor, scale, dimensions, aesthetic attributes, material properties, internal structures, and/or mechanical properties, which are formed according to any of the disclosed methods, approaches, processes, or variations thereof, using any devices, equipment, apparatuses, systems, or variations thereof, using any of the build material, printing mixture, ink, yield-stress support material, or other material compositions described herein or variations thereof, are all contemplated and covered by the present disclosure. None of the examples provided are intended to, nor should they, limit in any way the scope of the present disclosure.

[0329] Every document cited or referenced herein, including any cross referenced or related patent or application is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document and/or the mention of methods or apparatuses as being conventional, typical, usual, or the like is not, and should not be taken as an acknowledgement or any form of suggestion that the reference or mentioned method/apparatus is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention or forms part of the common general knowledge in any country in the world. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0330] The various portions of the present disclosure, such as the Background, Summary, Brief Description of the Drawings, and Abstract sections, are provided to comply with requirements of the MPEP and are not to be considered an admission of prior art or a suggestion that any portion or part of the disclosure constitutes common general knowledge in any country in the world. The present disclosure is provided as a discussion of the inventor’s own work and improvements based on the inventor’ s own work. See, e.g. , Riverwood Int ’I Corp. v. R.A. Jones & Co., 324 F.3d 1346, 1354 (Fed. Cir. 2003).

Claims

1. A method comprising: printing one or more volumes of a printing ink into a yield-stress support material to form an intermediate article, the printing ink comprising a curable material and a plurality of externally alignable particles, the yield-stress support material being configured to retain the one or more volumes of the printing ink in place within the yield-stress support material as the intermediate article during a period of time after the printing and before curing the curable material; communicating an external field towards at least a portion of the intermediate article, thereby causing at least partial alignment of at least a portion of the plurality of externally alignable particles in the printing ink in the intermediate article according to one or more alignment directions to form an aligned intermediate article; and at least partially curing the aligned intermediate article in the yield-stress support material to form a finished article.

2. The method of claim 1 , further comprising: causing a print nozzle to move along a predefined pathway through the yield-stress support material, wherein the printing the one or more volumes of the printing ink into the yield-stress support material to form the intermediate article is carried out using the print nozzle by communicating the one or more volumes of the printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material.

3. The method of claim 1, wherein the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field.

4. The method of claim 1, wherein the external field comprises a magnetic field.

5. The method of claim 1, further comprising: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink.

6. The method of claim 5, wherein the 2D platelets comprise 2D modified hexagonal boron nitride (mhBN) platelets comprising a coating of iron oxide (FesC ) nanoparticles formed on at least a portion of an external surface of the 2D mhBN platelets.

7. A method comprising: printing one or more volumes of a printing ink into a yield-stress support material to form an intermediate article, the printing ink comprising a curable material and a plurality of magnetically alignable particles suspended/dispersed within at least a portion of the curable material, the yield-stress support material being configured to retain the one or more volumes of the printing ink in place within the yield-stress support material as the intermediate article during a period of time after the printing and before curing the curable material; communicating an external magnetic field towards at least a portion of the intermediate article, thereby causing at least partial alignment of at least a portion of the plurality of magnetically alignable particles in the printing ink in the intermediate article according to one or more alignment directions to form an aligned intermediate article; and at least partially curing the curable material in the aligned intermediate article in the yield-stress support material to form a finished article.

8. The method of claim 7, further comprising: causing a print nozzle to move along a predefined pathway through the yield-stress support material, wherein the printing the one or more volumes of the printing ink into the yield-stress support material to form the intermediate article is carried out using the print nozzle bycommunicating the one or more volumes of the printing ink into the yield-stress support material at a plurality of points along the predefined pathway through the yield-stress support material.

9. The method of claim 7, wherein the yield-stress support material is supported on a rotatable platform positioned between two or more components of an external field generator configured to generate the external field.

10. The method of claim 9, further comprising: rotating the rotatable platform, while exposing the intermediate structured article in the yield-stress support material to the external field, to cause at least partial alignment to of the printing material in the alignment direction.

11. The method of claim 7, wherein the yield-stress support material is configured to support the intermediate structured article such that a form factor of the intermediate structured article remains unchanged or substantially unchanged after formation of the intermediate structured article and before at least partially curing the intermediate structured article to form the finished structured article.

12. The method of claim 7, wherein the external field comprises a magnetic field.

13. The method of claim 7, further comprising: forming a curable liquid matrix; communicating two-dimensional (2D) platelets into the curable liquid matrix; and ultrasonicating the curable liquid matrix to homogenously disperse the 2D platelets in the curable liquid matrix to form the printing ink.

14. The method of claim 13, wherein the 2D platelets comprise 2D modified hexagonal boron nitride (mhBN) platelets comprising a coating of iron oxide (FesC ) nanoparticles formed on at least a portion of an external surface of the 2D mhBN platelets.

15. A method comprising: at least partially coating one or more outside surfaces of two-dimensional (2D) hexagonal boron nitride (hBN) platelets with a plurality of iron oxide (Fe?O i) nanoparticles to form 2D modified hBN (mhBN) platelets; mixing the 2D mhBN platelets into a resin to form a printing ink having a concentration of mhBN between about 10 wt.% and about 40 wt.%; printing one or more volumes of the printing ink into a yield-stress support material to form an intermediate article, wherein the yield-stress support material is configured to retain the one or more volumes of the printing ink in place within the yield-stress support material as the intermediate article during a period of time after the printing, wherein the printing is carried out using a printing nozzle that is dimensioned and configured such that the printing nozzle exerts a first at least partial alignment of some or all of the 2D mhBN platelets in the printing ink during the printing, wherein the yield-stress support material is retained within a support bath container positioned on a rotatable platform and between two or more magnets configured to generate a magnetic field within the support bath container; causing the two or more magnets to generate the magnetic field within the support bath container, thereby causing a second at least partial alignment of some or all of the 2D mhBN platelets in the intermediate article to form an aligned intermediate article; and at least partially curing the aligned intermediate article in the yield-stress support material to form a finished article.