WO2014149465A1 - Dispositifs de papier omniphobe - Google Patents

Dispositifs de papier omniphobe Download PDF

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Publication number
WO2014149465A1
WO2014149465A1 PCT/US2014/018680 US2014018680W WO2014149465A1 WO 2014149465 A1 WO2014149465 A1 WO 2014149465A1 US 2014018680 W US2014018680 W US 2014018680W WO 2014149465 A1 WO2014149465 A1 WO 2014149465A1
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Prior art keywords
paper
liquid
cellulosic substrate
omniphobic
cellulosic
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English (en)
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Ana C. GLAVAN
Ramses V. MARTINEZ
George M. Whitesides
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Harvard University
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Harvard University
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes

Definitions

  • This technology relates generally to paper based devices.
  • this invention relates to paper based devices having a low friction or high slip, omniphobic surface.
  • Paper is a useful substrate in applications that require low cost, flexibility, disposability, porosity, and adaptability to large-scale manufacturing. In recent years, it has become increasingly popular as a material for the construction of "high-tech” devices in consumer electronics, chemical and physical microelectromechanical systems (MEMS) sensors, user interfaces, electronic displays, cell-based assays and microfluidic devices.
  • MEMS microelectromechanical systems
  • the tendency of paper to absorb liquids (including water) limits its adoption as a substrate in liquid- handling applications in which wicking is not desirable, or in which moisture and humidity can cause deleterious effects (especially changes in mechanical and electrical properties). For such applications, paper must be made resistant to wetting by liquids, and to adsorption of liquids (especially water) from the atmosphere.
  • Methods to render paper hydrophobic include spraying alcohol suspensions of Si0 2 nanoparticles on surface of the paper, soaking in polystyrene solutions, patterning using photolithography with SU-8, wax printing, plasma processing, and treatment with silanizing reagents.
  • Organosilanes with hydrophobic organic groups have been used to make the hydrophilic hydroxyl-rich surfaces of cellulose-based materials hydrophobic following both gas- phase and solution immersion reactions.
  • Most methods require long reaction and processing times (usually longer than one hour), and immersion in solvents requires pre- or post- treatment steps (washing cycles to remove excess reagents or side products, drying, etc.); these processes typically produce surfaces that have limited hydrolytic stability, or limited repellency to liquids with surface tensions lower than that of water. They also often cause the paper to buckle or warp.
  • paper is transformed into an omniphobic material by exposure to vapors of a fluoroalkyl trichlorosilane.
  • the process is simple (e.g., conducted in a single step), and rapid ( ⁇ 5 min to transform paper to either
  • the treated paper repels water ( ⁇ ⁇ >140°), organic liquids with surface tensions as low as 28 mN/m, aqueous solutions containing ionic and non-ionic surfactants, and complex liquids such as blood (which contains salts, surfactants, and biological material such as cells, proteins, and lipids).
  • fluoroalkylated paper forms a "slippery" surface (paper slippery liquid-infused porous surface, or "paper SLIPS”) capable of repelling liquids with surface tensions as low as 15 mN/m.
  • paper SLIPS paper slippery liquid-infused porous surface
  • a device having a low friction, low adhesion surface includes a cellulosic substrate comprising a covalently functionalized surface comprising perfluorocarbon or fluorinated groups in an amount sufficient to provide an omniphobic surface; and an lubricating liquid infused into and coating over the cellulosic substrate to form an immobilized layer of the omniphobic liquid, wherein the cellulosic substrate comprises as least one fold, said fold selected to provide an article capable of transporting or holding liquid having a surface tension of greater than 15 mN/m without adhesion.
  • the at least one fold forms a V-shaped channel.
  • the at least one fold forms a switch that is capable of directing the direction of fluid flow.
  • the at least one fold forms a well that is capable of holding a liquid.
  • the article is gas permeable.
  • the cellulosic substrate is selected from the group consisting of paper, cellulose derivatives, woven cellulosic materials, and non-woven cellulosic materials.
  • the paper is selected from the group consisting of chromatography paper, card stock, filter paper, vellum paper, printing paper, wrapping paper, ledger paper, bank paper, bond paper, blotting paper, drawing paper, fish paper, tissue paper, paper towel, wax paper, and photography paper.
  • covalently functionalized surface comprises a fluorinated group linked to the cellulosic surface through a siloxane linker.
  • a method of making a device having a low friction, low adhesion surface includes providing a cellulosic substrate comprising a covalently functionalized surface comprising perfluorocarbon or fluorinated groups in an amount sufficient to provide an omniphobic surface; infusing an lubricating liquid into and over the cellulosic substrate to form an immobilized layer of the omniphobic liquid, and folding the cellulosic substrate to provide a structure selected to provide an article capable of transporting or holding liquid having a surface tension of greater than 15 mN/m.
  • the at least one fold forms a V-shaped channel, or forms a switch that is capable of directing the direction of fluid flow, or forms a well that is capable of holding a liquid.
  • providing a cellulosic substrate comprising a covalently functionalized surface occurs before folding the cellulosic substrate.
  • providing a cellulosic substrate comprising a covalently functionalized surface occurs after folding the cellulosic substrate.
  • the membrane can include a cellulosic substrate comprising a covalently functionalized surface comprising fluorinated groups in an amount sufficient to provide an omniphobic surface; and a lubricating liquid infused into and coating over the cellulosic substrate to form an immobilized layer of the omniphobic liquid, a first liquid having a surface tension of greater than 15 mN/m disposed adjacent to a first side of the membrane, and a second liquid comprising water disposed against a second side of the membrane, wherein the membrane prevents mixing of the first and second liquids.
  • FIG. 1 is a schematic illustration of (a) the folds introduced into a cellulosic substrate functionalized to be omniphobic and infused with an omniphobic liquid to form paper SLIPS and (b) the folded device according to one or more embodiments.
  • FIG. 2 shows (a) representative images of water droplets on silanized paper; (b) static contact angles ⁇ ⁇ , and contact angle hysteresis ( ⁇ ⁇ - ⁇ ⁇ ) of water on silanized paper for three types of paper with different surface functionalization (identified on the x-axis as Ci H (methyl), Cio H (decyl), C 8 F (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl), Ci 0 F (3,3,4,4,5,5,6,6,
  • Ci2 F 3,3,4,4,5,5,6,6,7,7,8,8,9,9, 10,10,
  • FIG. 4 is a representation of 3-D "slippery" structures fabricated by folding and creasing omniphobic paper impregnated with a perfluoropolyether lubricant (Krytox® GPL 105), demonstrating that (a) a slippery "channel" formed by successive V-pleats in a paper SLIP can guide the transport of liquid droplets of dyed methanol (right) and dyed toluene (left) using S and (b)-(c) a fluidic switch formed by folding in a pre-defined geometry can direct the flow liquid in different direction by tilting.
  • a slippery "channel" formed by successive V-pleats in a paper SLIP can guide the transport of liquid droplets of dyed methanol (right) and dyed toluene (left) using S and (b)-(c) a fluidic switch formed by folding in a pre-defined geometry can direct the flow liquid in different direction by tilting.
  • FIG. 5 shows the crease pattern for the fabrication of channels and switches shown in FIG. 4.
  • FIG. 6 is a representation of omniphobic microtiter plates fabricated by creasing and folding of fluorinated paper to form (a) a square array of re-entrant honeycomb cells able to stably hold in each well 500 of (b) aqueous solutions (Dulbecco's Modified Eagle Medium), and (c) a negative Poisson ratio structure based on a triangular array of re-entrant honeycomb cells able to stably hold in each well 500 of (d) organic liquids (toluene dyed with Sudan I).
  • FIG. 7 shows the crease pattern for the fabrication of a multiwell plate shown in FIG 6.
  • FIG. 8 provides a schematic illustration of the system and process used for silanization according to one or more embodiments.
  • paper slippery porous liquid-infused surfaces paper SLIPS
  • FIG. 15 provides (a) a comparison of apparent contact angles and contact angle hysteresis ⁇ 9 a -9 r ) as a function of surface tension of test liquids (indicated) for SLIPS fabricated from Gel Blot, Whatman #1 and Whatman #50 paper silanized with Cio F and impregnated with a perfluoropolyether lubricant (DupontTM Krytox® GPL 105)1 and (b) a plot of the cosine of the predicted equilibrium contact angle— calculated with the assumption that the liquids wet a hypothetical flat surface composed solely of perfluoropolyether lubricant— versus the cosine of the measured apparent angle of liquids with the paper SLIPS; the diagonal dashed line is drawn to guide the eye to show the case of perfect correlation.
  • Cellulose is a polysaccharide consisting of glucose units. The hydroxyl groups are reactive and lend themselves to functionalization with a variety of agents. Cellulose can be rendered omniphobic by formation of a perfluoro or fluoroalkyl surface.
  • perfluorocarbon group is meant to include chemical species or moieties that are made up of only carbon and fluorine.
  • a perfluoroalkyl group is an alkyl group in which all hydrogens have been replace by fluorine.
  • fluorinated group is meant to include chemical species or moieties that include carbon and fluorine, but which may also include other atoms. Most commonly the additional atoms are hydrogen.
  • a fluoroalkyl group is an alkyl group in which some of the hydrogens have been replace by fluorine. The presence of additional atoms is selected to maintain the omniphobic properties typically imparted by the fluorine atoms in the groups. Fluorinated is a more general description that include partial and/or complete substation by fluorine.
  • omniphobic means a surface or material that is both hydrophobic and oleophobic. A material is considered to be hydrophobic when it exhibits a contact angle greater than 90 ° with water. A material is considered to be oleophobic when it exhibits an angle higher than 90 ° with hexadecane.
  • paper is transformed into an omniphobic material by exposure to vapors of a fluoridated or perfluorocarbon containing species, e.g., fluoroalkyl trichlorosilane, which react with the hydroxyl groups of the paper to form long fluoridated or perfluorocarbon chains of grafted siloxane molecules. It is simple (single step), rapid ( ⁇ 5 min to completion) and low-cost.
  • a fluoridated or perfluorocarbon containing species e.g., fluoroalkyl trichlorosilane
  • Part of the omniphobicity of organosilane-functionalized paper reflects its textured surface— a mixture of small fibers and voids— which enables it to form metastable composite solid-liquid-air interfaces.
  • This architecture one comprising voids and solid structures— is the basis of the omniphobic surface.
  • the propensity of the treated paper to resist wetting by liquids with a wide range of surface tensions correlates with the length and degree of fluorination of the organosilane, and with the roughness of the paper.
  • the omniphobic paper is wet with a lubricating liquid.
  • a lubricating liquid it is meant that the liquid is able to spread out and wet, e.g., lubricate, the omniphobic paper.
  • the lubricating liquid is a low surface tension, e.g., ⁇ 15 mN/m, liquid, in which some but not necessarily all C-H bonds have been replaced with C-F bonds. Treatment of the omniphobic paper in this way further increases the ability of fluorinated paper to resist wetting by low surface tension liquids ( ⁇ 15 mN/m).
  • Paper SLIPS can be used to prepare functional devices by taking advantage of their ability to be manipulated— e.g., folded, creased, wound or rolled— into structures that can be used as fluid flow channels, well plates, and switches.
  • paper SLIPS can be folded into simple channels for directing the passage of fluids from one location to another.
  • the fluid channels can be simple V-shape folds, as in the shape of a fan as shown in FIG. 1.
  • FIG. 1A illustrates the folds introduced into the paper SLIPS, in which dashed fold lines indicate a crease line in the paper away from the viewer and the solid fold lines indicate a crease line in the paper towards the viewer.
  • the resultant folded paper SLIPS is shown in FIG. IB.
  • the V-channels can serve as simple fluid conduits. Because the paper SLIPS exhibits minimal adhesion and sticking of water-based fluids, such as biological fluids, the paper SLIPS channels are useful conduits for fluid transport without loss or sticking.
  • Paper SLIPS possesses several distinguishing and advantageous properties:
  • Paper SLIPS devices are prepared using a cellulosic substrate that has been covalently modified to increase its hydrophobicity and omniphobicity.
  • the cellulosic substrate can be covalently modified using any suitable methodology, as discussed below.
  • Cellulose is a polysaccharide including a linear chain of several hundred to over ten thousand ⁇ (1 ⁇ 4) linked D-glucose units. Cellulose is mainly used to produce paperboard and paper.
  • a cellulosic substrate includes articles of manufacture such as paper and cardboard that are made primarily of cellulose. It also includes modified cellulose, for example where the hydroxyl groups of cellulose can be partially or fully reacted with various reagents to afford derivatives with useful properties such as nitrocellulose, cellulose esters and cellulose ethers.
  • the cellulosic substrate is flexible.
  • the cellulosic substrate can be bent through its thinnest dimension, rolled around a cylindrical rod with a diameter of no more than two inches, and return to a flat configuration without damaging the integrity of the substrate. Due to this flexibility, paper SLIPS devices fabricated from the cellulosic substrate can be treated in this fashion without damaging the integrity and/or functionality of the resultant folded device.
  • the cellulosic substrate can be folded, creased, or otherwise mechanically shaped to impart structure and function to a device formed from the cellulosic substrate.
  • suitable substrates include cellulose; derivatives of cellulose such as nitrocellulose or cellulose acetate; paper (e.g., craft paper, card stock, filter paper,
  • chromatography paper woven cellulosic materials; non-woven cellulosic materials; and thin films of wood that have been covalently modified to increase their omniphobicity, as discussed below.
  • the cellulosic substrate is paper.
  • Paper is inexpensive, widely available, readily patterned, thin, lightweight, and can be disposed of with minimal environmental impact.
  • a variety of grades of paper are available, permitting the selection of a paper substrate with the weight (i.e., grammage), thickness and/or rigidity and surface characteristics (i.e., chemical reactivity, hydrophobicity, and/or roughness), desired for the fabrication of a particular microfluidic device.
  • Suitable papers include, but are not limited to, chromatography paper, card stock, filter paper, vellum paper, printing paper, wrapping paper, ledger paper, bank paper, bond paper, blotting paper, drawing paper, fish paper, tissue paper, paper towel, wax paper, and photography paper.
  • Exemplary paper includes cardstock paper, which is particularly suitable as the cellulosic material is lightweight and flexible, sufficiently smooth to create a tight seal with tape and inexpensive; it is also thick enough (300 ⁇ ) to retain mechanical stability while
  • the cellulosic substrate is paper having a grammage, expressed in terms of grams per square meter (g/m 2 ), of greater than 50, 60, 70, 75, 85, 100, 125, 150, 175, 200, 225, or 250.
  • the cellulosic substrates can be covalently modified to provide an omniphobic surface using any suitable synthetic methodology.
  • hydroxyl groups present on the surface of the cellulosic substrate may be covalently functionalized by silanization, acylation, or by epoxide, aziridine, or thiirane ring opening.
  • the cellulosic substrate is treated with a volatile reagent to increase its oleophobicity.
  • suitable groups include linear, branched, or cyclic perfluoro or fluoroalkyl groups; linear, branched, or cyclic perfluorinated or fluorinated alkenyl groups; linear, branched, or cyclic perfluorinated or fluorinated alkynyl groups, aryl groups, optionally substituted with between one and five substituents individually selected from linear, branched, or cyclic perfluoro or fluorinated, linear, branched, or cyclic perfluorinated or fluorinated alkenyl, linear, branched, or cyclic perfluorinated or fluorinated alkynyl, perfluorinated or fluorinated alkoxy, perfluorinated or fluorinated amino, halogen, nitrile, CF 3 , ester, amide, aryl, and heteroaryl.
  • the omniphobic group is an aryl ring substituted with fluorine atoms and/or trifluoromethyl groups, or a linear or branched alkyl group substituted with one or more halogen atoms.
  • the introduction of halogenated functional groups via glycosidic linkages increases the omniphobicity of the cellulosic surface.
  • hydrophobic groups include linear, branched, or cyclic alkyl groups; linear, branched, or cyclic alkenyl groups; linear, branched, or cyclic alkynyl groups, aryl groups, heteroaryl groups, optionally substituted with between one and five substituents individually selected from linear, branched, or cyclic alkyl, linear, branched, or cyclic alkenyl, linear, branched, or cyclic alkynyl, alkoxy, amino, halogen, nitrile, CF 3 , ester, amide, aryl, and heteroaryl.
  • the hydrophobic group may also be a fluorinated or perfluorinated analogs of any of the groups described above.
  • the surface hydroxyl groups of the cellulosic substrate i.e., the cellulose fibers
  • Suitable silanes include linear or branched fluoroalkyl or perfluoroalkyl trihalosilanes, and fluoroalkyl or perfluoroalkyl aminosilanes.
  • the cellulosic substrate is reacted with one or more fluoroalkyl or perfluoroalkyl trichlorosilanes, such as (tridecafluoro- 1,1,2,2-tetrahydrooctyl) trichlorosilane, to form a fluorinated, highly textured, omniphobic surface on the cellulosic substrate.
  • the surface groups may have all or a portion of the hydrogen atoms replaced by fluorine atoms. If there are sufficient C-F bonds in the molecule, the surface free energy of the solid can be lowered sufficiently to render it omniphobic.
  • the silanization treatment does not degrade the physical properties of the paper and does not require pre- or post- treatment steps (e.g. washing to remove reagents or side products, drying, etc.).
  • exemplary commercially available silanes (3,3,4,4,5,5,6,6, 7,7,8,8,9,9,10,10,10- heptadecafluorodecyl) trichlorosilane, CF 3 -(CF 2 )7-CH 2 -CH 2 -SiCl 3 (CIOF), and decyl
  • the paper can be silanized before or after forming the device into its final form, e.g., by folding and creasing. Silanizing after folding can avoid damaging the organosilane layer or exposing cellulose fibers that had not come in contact with vapors of organosilane; however, the more complex surfaces may be more difficult to obtain complete coverage.
  • Treatment of paper with an organosilane (either R H SiCl3 or R F SiCl 3 ) in the vapor phase renders paper highly repellent to pure water. Paper treated with an organosilane (either R H SiCl 3 or R F SiCl 3 ) can be referred herein to as R H paper or R F paper, respectively.
  • FIG. 2A shows that silanization rendered paper highly hydrophobic. Water was no longer wicked into the paper, but instead formed droplets on the surface with apparent static contact angles, ⁇ ⁇ , between 130° and 160°, and with contact angle hysteresis from 7° to 20°.
  • the apparent contact angle of each type of functionalized paper increased (modestly) for the most part with the chain length and degree of fluorination of the organosilane, while the hysteresis did not show any noticeable trends (FIG.2B).
  • the surface hydroxy 1 groups of the cellulosic substrate are acylated by reaction, for example, with one or more perfluoro or fluoroalkyl groups functionalized with an acid chloride.
  • the cellulosic substrate can also be covalently modified by treatment with a hydrophobic group substituted with one or more epoxide or thiirane rings.
  • the omniphobicity/oleophilicity of the covalently modified cellulosic substrate can be quantitatively assessed by measuring the contact angle of a water droplet on the substrate surface using a goniometer.
  • the omniphobicity/oleophilicity of the covalently modified cellulosic substrate can be qualitatively assessed by rolling droplets of water and/or hexane on the surface of the modified paper to evaluate the wettability of the surface.
  • the covalently modified omniphobic cellulosic substrate (prior to introduction of a low surface tension perfluorinated liquid) is substantially impermeable to aqueous solutions.
  • the covalently modified cellulosic substrate has a contact angle with water, as measured using a goniometer, of more than 90° ⁇ i.e., it is hydrophobic).
  • the covalently modified cellulosic substrate has a contact angle with water of more than about 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, 140°, 145°, 150°, or 155°.
  • An omniphobic surface exhibits contact angles higher than 90 ° with both water and hexadecane.
  • Covalent attachment of the modifying reagent to the cellulosic substrate can be confirmed using appropriate molecular and surface analysis methods, including reflectance FTIR and XPS.
  • at least 5%, more preferably at least 25%, more preferably at least 35%, more preferably at least 50%>, most preferably at least 75% of the pendant -OH groups present on the cellulosic backbone are covalently modified.
  • more than 80% of the pendant -OH groups present on the cellulosic backbone are covalently modified.
  • the covalently modified paper is rendered repellant to liquids and other objects by infusing the paper with a low surface tension lubricating liquid.
  • the fluid used to impregnate the omniphobic paper to make the paper SLIPS can be any kind of low surface tension fluorinated oil, such as perfluoropolyether, perfluorocarbons, perfluoroalkylether, perfluoropolyalkylether.
  • Other lubricants can also be used to impregnate omniphobic paper to create paper SLIPS like fluorinated grease, Teflon lubricants and greases.
  • the liquid molecules may have all or a portion of the hydrogen atoms replaced by fluorine atoms.
  • C-H bonds might be desirable to retain some C-H bonds in order that the compound is stable. If there are sufficient C-F bonds in the molecule, the surface free energy can be lowered sufficiently to render it wetting to the omniphobic paper.
  • the lubricating layer can be prepared from a variety of fluids. Perfluorinated organic liquids, in particular, are suitable for use in folded applications.
  • the lubricating layer is perfluorinated oil, non-limiting examples of which include PFC oils such as FC-43, FC- 70, perfluorotripropylamine, perfluorotripentylamine, perfluorotributylamine, perfluorodecalin, perfluorooctane, perfluorobutane, perfluoropropane, perfluoropentane, perfluorohexane, perfluoroheptane, perfluorononane, perfluorodecane, perfluorododecane, perfluorooctyl bromide, perfluoro(2-butyl-tetrahydrofurane), perfluoroperhydrophenanthrene, perfluoroethylcyclohexane, perflufluorofluor
  • the viscosity of the lubricating layer can be chosen for particular applications.
  • the viscosity of the lubricating oil can be ⁇ 1 cSt, ⁇ 10 cSt, ⁇ 100 cSt, ⁇ 1000 cSt, or ⁇ 10,000 cSt.
  • the lubricating layer has a low freezing temperature, such as less than -5 °C, -25 °C, or -50 °C.
  • a lubricating layer with a low freezing temperature allows the layer to remain liquid in low temperatures to maintain the ability of the combination of the lubricating layer and functionalized surface to repel a variety of liquids or solidified fluids, such as ice and the like.
  • the lubricating layer can be applied in a thickness sufficient to cover the surface of the cellulosic substrate.
  • the amount of low surface tension perfluorinated liquid used is sufficient to completely wick into the pores of the paper and to cover the upper surface of the substrate. Large excesses of the low surface tension perfluorinated liquid is not needed, as the low friction slippery surface arises from the interaction of the immobilized liquid located immediately above the paper upper surface.
  • the lubricating layer is applied at a thickness sufficient to form a
  • the lubricating layer is applied at a thickness of 10 nm to 10 ⁇ on the substrate. In other embodiments, the lubricating layer is applied at a thickness of 10 ⁇ to 10 mm on the substrate.
  • FIG. 3(A)-3(C) The dependence of static contact angles on surface tension for 10 uL droplets of liquid is shown in FIG. 3(A)-3(C) for blot paper, Whatman #1 and Whatman #50, respectively.
  • the liquids used in these experiments and their respective surface tensions ( ⁇ ) at 20°C in mN/m are (literature values: pentane (15.5), anhydrous ethanol (22.3), hexadecane (27.4), DMF (37.1), ethylene glycol (46.3), thiodiglycol (54.0), glycerol (63.7), water (72.8), 6m NaCl (82.6).
  • the grey area indicates liquids that spontaneously spread onto the functionalized substrate through capillary wicking. Test liquids with lower surface tensions wicked into the paper.
  • the lubricating layer has a low evaporation rate or a low vapor pressure.
  • the vapor pressure of the lubricating liquid can be less than 10 mmHg at 25 °C, less than 5 mmHg at 25 °C, less than 2 mmHg at 25 °C, less than 1 mmHg at 25 °C, less than 0.5 mmHg at 25 °C, or less than 0.1 mmHg at 25 °C.
  • the surface can remain liquid repellant for a period longer than 1 hour, or longer than 6 hours, or longer than 24 hours, longer than a week, or longer than a year or more.
  • the lubricating liquid can be applied to the surface by wicking, spin coating, pipetting drops of lubricating liquid onto the surface, or dipping the surface into a reservoir containing the lubricating liquid. In some embodiments, any excess lubricating liquid can be removed by spinning the coated article or by drawing a squeegee across the surface or flushing and rinsing with another liquid.
  • Paper SLIPS is highly omniphobic. Both water and hydrophobic organic liquids are not adsorbed on the surface, but instead formed droplets on the surface that roll off when the surface is tilted. Furthermore, the paper SLIPS surface remains visually free of residue after contact with a range of liquids. Blood, toluene, and diethyl ether all slide off the paper SLIPS when the surface is tilted.
  • the non-wetting of silanized paper by biological fluids is important for its use in applications such as bioanalysis, cell culture, and drug discovery and development.
  • Device made of paper SLIPS may provide advantageous anti-bioadhesion and anti-biofouling properties.
  • the paper SLIPS is permeable to gasses and therefore can be used as a gas sensor or be used in applications for which gas permeability is desirable (such as the elimination of volatile materials from a mixture by evaporation, removing gas contaminants from a sample, or in reactions that require gas exchange).
  • the paper SLIPS can be folded, creased, rolled or wound into 2 dimensional and 3 dimensional structures that can be used to direct the flow of liquid.
  • the principals of origami can be used to prepare structures with a wide range of complexity and functions.
  • the mechanical flexibility and foldability of the paper SLIPS allows it to be formed into a range of shapes, such as microtiter plates, from single sheets of paper using the principles of origami.
  • FIG. 4A is a paper SLIPs v-pleated device demonstrating the ability to hold liquid (in the valleys of a V-pleat) and direct it along a corrugated channel defined by a series of adjacent V-pleats.
  • FIGS. 4B and 4C illustrate a simple switch made by combining tilting with a pre-designed folded geometrical path.
  • FIG. 4B When the structure is tilted towards the left (FIG.4B), the liquid droplet moves along the left hand channel, while when the structure is tilted to the right, the path the liquid droplet takes is changed and the droplet moves along the right-hand channel (FIG. 4C).
  • the fold lines for the paper SLIPS used to create the V-channel design are shown in FIG. 5, where solid lines and dashed lines indicate a crease line away from and towards the viewer, respectively.
  • Folding can also be used to design three-dimensional structures, such as the microtiter plates illustrated in FIGs. 6A-D.
  • FIG. 6A shows a square array of re-entrant honeycomb cells; the same microtiter plate filled with aqueous fluid is shown in FIG. 6B.
  • FIG. 6C shows a negative Poisson ratio structure based on a triangular array of re-entrant honeycomb cells; the same microtiter plate filled with hydrophobic organic fluid is shown in FIG. 6D.
  • Origami principles can be applied to SLIPS to make a great variety of structures using paper SLIPS as a substrate. Structures like reservoirs and channels of different geometries can be fabricated like this.
  • FIG. 7 shows the crease patterns used in making the microwell plate structures shown in FIG. 6 from paper SLIPS, where solid lines and dashed lines indicate a crease line away from and towards the viewer, respectively.
  • Whatman chromatography paper was used as the starting material because it is uniform in structure and free of hydrophobic binders or coatings that could interfere with, or mask, the effect of silanization.
  • Three types of papers were investigated: Whatman Gel Blot paper, Whatman #1 paper, and Whatman #50 paper.
  • FIG. 2C shows SEM photomicrographs of the paper porous structure.
  • the height RMS roughness was measured with a Taylor-Hobson CCI HD Optical Profiler according to the IS025178 norm.
  • the CCI method is based on the cross-coherence analysis of two low-coherence light sources, the beam reflected from the sample and a reference beam reflected from a reference mirror. Paper has a low reflectance that hinders the application of interferometry techniques.
  • a conformal thin layer of Au ⁇ 4 nm
  • organosilane reagents (RS1CI3) of varying chain length and fluorination of the organosilane were investigated: i) methyltricholorosilane (CH3S1CI3, "Ci "); ⁇ ) decyltrichlorosilane (CH 3 (CH 2 ) 9 SiCl3, “Cio "); iii) (3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluorooctyl) trichlorosilane (CF 3 (CF 2 ) 5 CH2CH 2 SiCl 3 , "C 8 F "); iv)
  • the silanization reaction was performed in a vacuum oven at 95 °C and 30 mbar using a solution of the organosilane (-10 mL of a -30 mM solution in toluene) to supply a useful concentration of the silanizing reagent in the vapor phase.
  • the organosilane was allowed to react with the hydroxyl-rich cellulose paper surfaces for 5 min (this time and temperature are not optimized).
  • Each experiment typically required approximately 100 mg of silane in 5 mL of anhydrous toluene. Diffusion inside the reaction chamber is sufficient for an even distribution of the silane within the chamber. This process makes it possible to functionalize the areas of paper (>100 cm 2 ) required for experimental work rapidly, using low quantities of organosilane and solvent.
  • FIG. 8 provides a schematic illustration of the system and process used for silanization.
  • X c ranged between 1.6 mm (for pentane) and 2.7 mm (for water).
  • PCR polymerase chain reactions
  • the contact angle measurements were performed using a contact angle measurement system (Rame-Hart model 500-F1 , Rame-Hart Instrument Co.) at room temperature (20 - 25 °C) with -20% relative humidity.
  • the droplet volume for the measurement was ⁇ 10 (unless otherwise specified).
  • the advancing and receding contact angles were measured by the sessile drop method, which involves expanding or contracting a contact angle droplet by adding or withdrawing fluid in 1 ⁇ ⁇ increments.
  • the droplet profile was fitted to a spherical profile using the software provided by the system.
  • the advancing contact angles are measured at the leading droplet edge when the value of the contact angle remained constant and solid/liquid interface started to increase; the receding angles were measured at the trailing droplet edge when the value of the contact angle remained constant and the solid/liquid interface started to decrease.
  • FIG. 1 1 A shows representative images of the paper surfaces after the blood had rolled off. There are significantly more traces of blood left on the R H papers than on the omniphobic papers. Papers treated with the organosilanes with the longer fluoroalkyl chains (Cio F and Ci 2 F ) showed no detectable trace of blood on the surface after roll- off.
  • FIG. 1 1C is a bar graph showing the stain area (mm 2 ) for each of the treated papers shown in FIG. 1 1A.
  • FIG. 1 IB shows the roll-off angles measured for these papers.
  • Hydrophobic papers had significantly higher roll-off angles than omniphobic papers.
  • the blood drops adhered so strongly to Cio H treated surfaces that the droplets did not fall off even when the paper was turned upside down (i.e. roll-off angle > 180°).
  • the state characterized by high adhesion and high contact angles has been termed the "petal effect" and is attributed to hierarchical roughness (multiple length-scales of features) on surfaces.
  • Bioanalytical devices fabricated using silanized paper can be disposed of by incineration; we wished to estimate the environmental impact of burning omniphobic paper.
  • the elemental analysis of the fluorinated papers suggests that the incineration of a 1 cm 2 device at T ⁇ 1500 °C can produce at most 34 ⁇ g of a perfluoroalkyl carboxylic acid; under more stringent conditions (temperatures above 1500 °C), this content of fluorine could lead to the formation of a maximum of ca. 29 ⁇ g of HF, or a maximum of ca. 49 ⁇ g of COF 2 .
  • the distribution of products includes COF 2 , CF 4 , CO, and C0 2 , with COF 2 and C0 2 being the most abundant when the combustion occurs with 20% 0 2 .
  • the toxic volatile compounds, COF 2 and HF have threshold limits for short-term exposure of 2ppm (5.4 mg/m 3 ) for COF 2 and 2 ppm (1.7 mg/m 3 ) for HF.
  • the omniphobic paper is burned in a simple set-up, with no high-temperature combustion catalyst present in the system when the paper is burned, the temperature of the flame is likely not high enough to allow the decomposition of the fluoroalkyl chains. It is, however, sufficiently high ⁇ to allow the breaking of the C-Si bond and the oxidation of the terminal carbon atom to yield terminally oxidized fluoroalkyl species.
  • Ci 2 F functionalized with Ci 2 F contains ⁇ 7 ⁇ 10 "8 moles Ci 2 F , corresponding to ⁇ 4 ⁇ 10 16 molecules Ci 2 F per cm 2 of paper.
  • one cm 2 of functionalized Whatman #1 and Whatman #50 papers contain ⁇ 6 ⁇ 10 "9 moles or ⁇ 4 ⁇ 10 15 molecules Ci 2 F per cm 2 of paper.
  • the incineration of 1 cm 2 of Gel Blot paper functionalized with Ci 2 F will produce at most 34 ⁇ g of perfluoroalkylcarboxylic acid (C 12 H 3 F 21 O 2 ), corresponding to a maximum of ca. 29 ⁇ g of HF, or a maximum of ca. 49 ⁇ g of COF 2 .
  • the amounts of fluorinated products released by the incineration of 1 cm 2 of Whatman #1 and Whatman #50 papers are maximum ca. 3 ⁇ g of perfluoroalkylcarboxylic acid, or ca. 2.6 ⁇ g of HF and ca. 4.3 ⁇ g of COF 2 .
  • the wettability of silanized paper by common buffers was investigated, since the surface tension of an aqueous buffer can be dramatically altered by the addition of surfactants or other solutes.
  • the buffers surveyed include phosphate-buffered saline (PBS) buffer, Tris buffer, lx Taq Buffer (used for polymerase chain reactions), Tris-Gly buffer (typically used in capillary electrophoresis); Lysogeny broth (LB) or Dulbecco's Modified Eagle Medium (DMEM)— buffers typically used for mammalian or bacterial cell culture.
  • PBS phosphate-buffered saline
  • Tris buffer Tris buffer
  • lx Taq Buffer used for polymerase chain reactions
  • Tris-Gly buffer typically used in capillary electrophoresis
  • LB Lys
  • hydrophobic and omniphobic surfaces are in their ability to resist wetting by aqueous solutions of nonionic surfactants. These surfactants reduce the surface tension of pure water to ⁇ 30 mN/m when present at or above the critical micelle concentration (cmc).
  • Nonionic surfactants are present in standard buffers used for PCR reactions, such as the lx Taq Buffer. When used above the cmc, nonionic surfactants containing
  • polyethylene oxide chains e.g. IGEPAL CA@630, Triton X-100 and Tween 20
  • R H wetted R H
  • R F paper surfaces wetted R F , but not the R F paper surfaces, as is illustrated in FIG. 13-13D in the plots of contact angles for variously treated paper.
  • the non-fluorinated surfaces are wetted by 0.05% TritonX, 0.07% Tween 20 and 0.05% IGEPAL@CA630. Therefore, omniphobic papers provide the additional advantage that they are compatible with applications that require buffers containing nonionic surfactants.
  • Omniphobic paper Infused with a perfluorinated liquid forms an omniphobic "SLIPS" surface exhibiting very low contact angle hysteresis.
  • Lubricating fluid (DupontTM Krytox® GPL 105), was added to the surfaces (-50 by pipette to impregnate the paper and form a coating film.
  • the fluid spontaneously spread onto the whole substrate through capillary wicking. Tilting the surface and mildly applying compressed air removed the excess of lubricating fluid.
  • the liquid spontaneously spreads onto the whole substrate through capillary wicking, and the large pores in paper facilitate the infiltration and retention of the lubricating perfluoropolyether to form a continuous overlying film.
  • FIGS. 14A shows how omniphobic paper can serve as a substrate for SLIPS— "Slippery Liquid-infused Porous Substrates” with remarkably low hysteresis towards most liquids.
  • FIG. 15A demonstrates that paper SLIPS show omniphobic behavior, with contact- angle hysteresis of the surface below 10° for all liquids we tested, and below 5° for most of them.
  • FIG. 15A provides a comparison of apparent contact angles and contact angle hysteresis ( ⁇ -dr) as a function of surface tension of test liquids (indicated) for SLIPS fabricated from Gel Blot, Whatman #1 and Whatman #50 paper silanized with Cio F and impregnated with a perfluoropolyether lubricant (DupontTM Krytox® GPL 105).
  • Paper SLIPS are also able to resist wetting by pentane, which has a surface tension of -15 mN/m. Since the wetting characteristics (apparent contact angles ⁇ ⁇ , and hysteresis, ⁇ ⁇ - ⁇ ) of the paper SLIPS did not vary for the three types of paper substrates, we hypothesized that the film of perfluoropolyether oil dominates the wetting characteristics of this material. [0102] To test this hypothesis, we measured the surface tension of the perfluoropolyether oil and the liquid-liquid interfacial tension between the perfluoropolyether oil and the test liquids using the pendant drop method. FIG.
  • 15B is a plot of the cosine of the predicted equilibrium contact angle— calculated with the assumption that the liquids wet a hypothetical flat surface composed solely of perfluoropolyether lubricant— versus the cosine of the measured apparent angle of liquids with the paper SLIPS.
  • the diagonal dashed line is drawn to guide the eye to show the case of perfect correlation.
  • a useful feature of paper SLIPS is their foldability, which can be exploited for low-cost fabrication of structures with desired functionalities.
  • Complex 3-D "slippery" structures of paper SLIPS can be easily fabricated using techniques based on (for example) origami directly from paper SLIPS, or from R F paper folded, then impregnated with a perfluoropolyether.
  • origami directly from paper SLIPS
  • R F paper folded then impregnated with a perfluoropolyether.
  • the fold lines for the paper SLIPS used to create the V-channel design is shown in FIG. 5. Mountain and valley folds are indicated by solid and dashed lines,
  • the mechanical flexibility of the omniphobic paper allowed us to form 3-D structures by folding the sheet of paper before or after functionalization. We created a simple switch by combining tilting with a pre-designed folded geometrical path. When the structure is tilted towards the left, the liquid droplet moves along the left hand channel, as shown in FIG. 4B. When the structure is tilted to the right, the path the liquid droplet takes is changed and the droplet moves along the right-hand channel (FIG. 4C).
  • Paper SLIPS allows (originally) planar sheets to be transformed with each into structures with complex topographies by folding.
  • FIG. 7 shows the crease patterns used in making the microwell plate structures shown in FIG. 6 from paper SLIPS. Mountain and valley folds are indicated by green and red dashed lines, respectively.
  • the mechanical flexibility of the omniphobic paper allowed us to form 3-D structures by folding the sheet of paper after impregnation with a perfluoropolyether (Krytox® GPL 105).

Landscapes

  • Paper (AREA)
  • Laminated Bodies (AREA)

Abstract

L'invention concerne une réaction en une étape, rapide pour la transformation de papier de cellulose en une matière omniphobe qui n'est pas humidifiée (θaρρ > 90°) par l'eau et les liquides organiques avec une tension de surface aussi basse que 28 mN/m. Lors de l'imprégnation par un lubrifiant, le papier omniphobe forme une matière glissante apte à repousser les liquides avec des tensions de surface aussi basses que 15 mN/m. Le papier à base de cellulose est disponible dans le commerce sous une diversité de formes, avec différentes rugosité, porosité, densité, épaisseur et flexibilité, dont toutes peuvent être converties en des matières omniphobes ou des SLIPS lors d'une fonctionnalisation de surface appropriée, ou lors d'une fonctionnalisation et d'une addition d'un lubrifiant, pour atteindre les besoins d'applications spécifiques.
PCT/US2014/018680 2013-03-15 2014-02-26 Dispositifs de papier omniphobe Ceased WO2014149465A1 (fr)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016120401A1 (fr) 2015-01-28 2016-08-04 Carl Zeiss Meditec Ag Tomographie en cohérence optique pour effectuer des mesures sur la rétine
EP3138676A1 (fr) 2015-09-04 2017-03-08 ETH Zurich Feuille de placage en bois insectifuge et revêtement de surface de papier
US20200333829A1 (en) * 2019-04-19 2020-10-22 Purdue Research Foundation Epidermal paper-based electronic devices
WO2020247355A1 (fr) * 2019-06-03 2020-12-10 Board Of Trustees Of Michigan State University Revêtements hautes-barrières et omniphobes biodégradables, articles associés et procédés associés
WO2020247762A1 (fr) * 2019-06-05 2020-12-10 Conocophillips Company Élimination de composants lourds en deux étapes dans un traitement de gnl
US11155732B2 (en) * 2018-08-21 2021-10-26 Board Of Trustees Of Michigan State University Biodegradable omniphobic coated articles and method for making
US11604025B2 (en) 2019-10-17 2023-03-14 Conocophillips Company Standalone high-pressure heavies removal unit for LNG processing
GB2611045A (en) * 2021-09-23 2023-03-29 Dyson Technology Ltd A serviceable part for use in an electrical appliance

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6123076A (en) * 1997-05-09 2000-09-26 Porous Media Corporation Hydrophobic barrier for filters and filter media
US20100192339A1 (en) * 2004-05-14 2010-08-05 Curt Binner Intravaginal device with fluid transport plates
WO2012100100A2 (fr) * 2011-01-19 2012-07-26 President And Fellows Of Harvard College Surfaces glissantes poreuses imprégnées de liquides et leur application biologique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6123076A (en) * 1997-05-09 2000-09-26 Porous Media Corporation Hydrophobic barrier for filters and filter media
US20100192339A1 (en) * 2004-05-14 2010-08-05 Curt Binner Intravaginal device with fluid transport plates
WO2012100100A2 (fr) * 2011-01-19 2012-07-26 President And Fellows Of Harvard College Surfaces glissantes poreuses imprégnées de liquides et leur application biologique

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016120401A1 (fr) 2015-01-28 2016-08-04 Carl Zeiss Meditec Ag Tomographie en cohérence optique pour effectuer des mesures sur la rétine
EP3138676A1 (fr) 2015-09-04 2017-03-08 ETH Zurich Feuille de placage en bois insectifuge et revêtement de surface de papier
WO2017037289A2 (fr) 2015-09-04 2017-03-09 ETH Zürich Placage de bois multi-répulsif et revêtement de surface de papier
US11155732B2 (en) * 2018-08-21 2021-10-26 Board Of Trustees Of Michigan State University Biodegradable omniphobic coated articles and method for making
US20200333829A1 (en) * 2019-04-19 2020-10-22 Purdue Research Foundation Epidermal paper-based electronic devices
WO2020214461A1 (fr) * 2019-04-19 2020-10-22 Purdue Research Foundation Dispositifs électroniques à base de papier épidermique
US12070315B2 (en) * 2019-04-19 2024-08-27 Purdue Research Foundation Epidermal paper-based electronic devices
US11814540B2 (en) 2019-06-03 2023-11-14 Board Of Trustees Of Michigan State University Biodegradable omniphobic and high-barrier coatings, related articles, and related methods
WO2020247355A1 (fr) * 2019-06-03 2020-12-10 Board Of Trustees Of Michigan State University Revêtements hautes-barrières et omniphobes biodégradables, articles associés et procédés associés
WO2020247762A1 (fr) * 2019-06-05 2020-12-10 Conocophillips Company Élimination de composants lourds en deux étapes dans un traitement de gnl
US12111101B2 (en) 2019-06-05 2024-10-08 Conocophillips Company Two-stage heavies removal in lng processing
US11604025B2 (en) 2019-10-17 2023-03-14 Conocophillips Company Standalone high-pressure heavies removal unit for LNG processing
WO2023047106A1 (fr) * 2021-09-23 2023-03-30 Dyson Technology Limited Pièce utilisable dans un appareil électrique
GB2611045A (en) * 2021-09-23 2023-03-29 Dyson Technology Ltd A serviceable part for use in an electrical appliance
CN117980052A (zh) * 2021-09-23 2024-05-03 戴森技术有限公司 用于电气器具的可维护部件

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