TW202016346A - A acrylamide nano coating and preparation method thereof - Google Patents

Abstract

The invention provides a acrylamide nano coating and a preparation method thereof. The acrylamide nano coating is characterized by exposing the substrate to a monomeric vapor atmosphere and chemically reacting on the surface of the substrate by plasma discharge to form a protective coating. The monomeric vapor is vaporized monomer 1 or monomer 2, or a mixture of monomer 1 and monomer 2. The method of the present application is used to form a denser and finer micro-convex structure on the surface of the substrate, so that the coating has excellent acid and alkali corrosion resistance and super-hydrophobic effect at a nanometer scale, and the contact angle can reach 150° or more.

Description

Acrylamide nano coating and preparation method thereof

The invention relates to the technical field of plasma chemical vapor deposition, in particular to a nano protective coating and a preparation method thereof.

As we all know, the low polarizability and strong electronegativity of fluorine atoms in fluorocarbon materials give fluorocarbon polymers many unique properties, such as high hydrophobicity and oleophobicity, chemical resistance, excellent weather resistance, etc., so they are widely used in In the fields of architectural coatings, textile industry, military industry, etc. Although fluoropolymers have many advantages, their monomers are expensive and difficult to form films using conventional coating methods. CN 106868473 A "Preparation method of liquid-repellent coating with gradient decreasing structure" uses plasma chemical vapor deposition technology to successfully deposit fluorocarbon materials containing acrylate structure and multifunctional unsaturated hydrocarbon derivatives to the base On the surface of the material, a protective coating with a gradient decreasing structure is formed, which has good barrier protection performance. However, after research, it was found that when the number of perfluoroalkyl carbon atoms in the monomer is less than 6, the hydrophobicity decreases significantly. CN 102471405 A "N-substituted (meth)acrylamide compounds containing fluoroalkyl groups, their polymers and their uses", liquid coating with N-substituted (methacrylamide) compounds containing fluoroalkyl groups A protective layer is formed on the surface of the treated sample to achieve the purpose of rust prevention and hydrophobicity, and is not restricted by the use of PFOA and PFOA analogs. It can still maintain excellent hydrophobic properties when the carbon number is below 6. However, the thickness of the coating layer obtained by this coating method is often above the micron level, which wastes a lot of monomers, resulting in increased costs.

Therefore, the N-substituted (acrylamide) containing fluoroalkyl groups is prepared by plasma technology with a nano-thickness coating, which can ensure its excellent hydrophobicity and protection in the case of low fluorinated carbon atoms Performance can avoid the waste of monomer.

In order to overcome the above shortcomings, the present invention provides an acrylamide nano-coating and a preparation method thereof. The invention uses plasma chemical vapor deposition technology to deposit olefin derivatives containing acrylamide structure and fluorine-containing alkyl acrylamide monomer onto the surface of the substrate, forming a nano-protective coating with a composite structure on the surface of the substrate Floor.

The present invention is achieved through the following technical solutions:

An acrylamide nano-coating, characterized in that the substrate is exposed to a monomer vapor atmosphere, and a chemical reaction occurs on the surface of the substrate by plasma discharge to form a protective coating;

The monomer vapor is vaporized monomer 1 or monomer 2, or a mixture of monomer 1 and monomer 2;

The monomer 1 has the structure represented by the following formula (I); the monomer 2 has the structure represented by the following formula (II);

單體1： （I）

Monomer 1: (I)

（II）Monomer 2:

(II)

Wherein, R ¹ , R ² , R ³ , R ⁶ , R ⁷ and R ^{8 are} independently selected from hydrogen, alkyl, aryl, halogen, haloalkyl, alkenyl or haloalkenyl, and X and Y are hydrogen or halogen;

（III）R ⁴ and R ^{5 are} independently selected from hydrogen, alkyl, aryl, halogen, haloalkyl or have the structure shown in formula (III):

(III)

R ¹¹ is a linear chain having 1 to 15 carbon atoms or containing a branched alkane subunit, and R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ are independently selected from hydrogen, alkyl, aryl, halogen or haloalkyl;

R ⁹ and R ^{10 are} independently selected from linear chains having 1 to 15 carbon atoms, branched-chain alkyl subunits or aryl subunits; or R ⁹ and R ¹⁰ are connected bonds;

m, n, p, and q are integers of 0-20, but m and n are not 0 at the same time, and p and q are not 0 at the same time.

In the present invention, R ¹ , R ² , R ³ , R ⁶ , R ⁷ , and R ⁸ are groups connected to unsaturated double bonds, and may be hydrophobic groups, wherein preferably, they are independently selected from hydrogen, Alkyl, aryl, halogen, haloalkyl, alkenyl or haloalkenyl; X and Y are hydrogen, or a substituent on the carbon chain of the alkyl group, may be selected from halogen.

R ⁴ and R ⁵ are groups connected to the N atom. Preferably, R ⁴ and R ⁵ have the structure represented by formula (III), because the structure of formula (III) makes monomer 2 have a bisacrylamide functional group, which is beneficial to The monomer 1 and the monomer 2 react further.

R ¹¹ is a bridging group between diacrylamide groups, which may be a straight chain with 1 to 15 carbon atoms or contain branched alkane subunits, and R ¹² , R ¹³ , R ¹⁴ , and R ¹⁵ are atoms with N atoms , Unsaturated double bond-connected hydrophobic group can be independently selected from hydrogen, alkyl, aryl, halogen or haloalkyl.

R ⁹ and R ¹⁰ are bridging carbon segments between the acrylamide functional group and the perfluoroalkyl group, and are independently selected from straight chains having 1 to 15 carbon atoms, alkyl subunits containing branched chains or containing aromatic groups Keide; or just a connected bond. The bridged carbon chain is a buffer segment between the functional group and the perfluoroalkyl group. The stability and easy availability of the monomer can be adjusted by the length and structure of the carbon chain. Further, R ¹ , R ² , R ³ , R ⁶ , R ⁷ , and R ^{8 are} independently selected from hydrogen, methyl, or fluorine groups, and X and Y are fluorine.

Further, R ⁹ and R ¹⁰ are short carbon chain bridging groups. The number of carbon atoms of the bridging group is too long to easily reduce the proportion of fluorine atoms in the monomer. R ⁹ and R ^{10 are} independently selected from the number of carbon atoms is 1 -5 linear alkylene.

Further, R ¹¹ is a linear alkane subunit having 3 to 10 carbon atoms. Monomer 1 is liquid at normal temperature and pressure.

Further, m and n are integers of 2-10. Monomer 2 is a fluorine-containing acrylamide having a boiling point of less than 400°C at normal temperature and pressure.

Further, the substrate is a solid material such as metal, optical instruments, clothing fabrics, electronic devices, or medical devices.

The invention also discloses a method for preparing the acrylamide nano-coating, which is characterized by the following steps:

(1) Place the substrate in the reaction chamber of the plasma chamber, and evacuate the vacuum in the reaction chamber to 0.1-1000 mTorr;

(2) Inject the plasma source gas, start the plasma discharge for deposition, and vaporize monomer 1 and/or monomer 2 into the reaction chamber for chemical vapor deposition reaction;

(3) Turn off the plasma discharge for deposition, pass clean compressed air or inert gas to return to normal pressure, open the cavity, and take out the substrate.

Further, in step (2), the monomer 1 and the monomer 2 are respectively introduced into a vacuum chamber;

Or, the monomer 1 and the monomer 2 are simultaneously led into the vacuum chamber;

Alternatively, the monomer 1 or the monomer 2 is first introduced into the vacuum chamber, and then the mixed steam of the monomer 1 and the monomer 2 is simultaneously introduced.

Further, the plasma source gas in step (2) is one or a mixture of several kinds of helium, argon, nitrogen, and hydrogen.

Further, the volume of the plasma chamber is 1L-5000 L;

The plasma source gas flow rate is 5-1000 sccm;

The flow rate of the monomer vapor is 1-2000 μL/min.

Preferably, in the step (2), after passing the plasma source gas and before the plasma discharge for deposition, a plasma discharge step for pretreatment of the substrate is further included.

After the plasma source gas is introduced in step (2), the pretreatment is started to perform pretreatment on the substrate with plasma discharge. The power of the plasma discharge in the pretreatment stage is 2-500W, and the continuous discharge time is 1-3600s.

After the pretreatment phase is completed, the deposition phase is entered (the plasma discharge for pretreatment is converted to a plasma discharge for deposition). The plasma discharge method and parameters of the two phases may be the same or different.

Further, in the step (2), the power of the plasma discharge for deposition is 2-500W, and the continuous discharge time is 600-20000s.

Further, the plasma discharge (plasma discharge for pretreatment and/or plasma discharge for deposition) is radio frequency discharge, microwave discharge, intermediate frequency discharge, Penning discharge or electric spark discharge.

Further, the plasma discharge (plasma discharge for pretreatment and/or plasma discharge for deposition) is a radio frequency discharge, and the energy output method for controlling the plasma radio frequency during the radio frequency discharge is pulse or continuous output. When the energy output mode is pulse output, the pulse width is 10μs-50ms and the repetition frequency is 20Hz-10kHz.

Further, the surface of the substrate is subjected to chemical corrosion and hydrophobic protection treatment using the coating of the present application.

Using the above technical solution, the present invention has the following beneficial effects:

Compared with the prior art, the present invention provides an acrylamide nano-coating and its preparation method:

(1) When two perfluoroalkyl groups are connected to the N atom of the monomer, due to the strong electronegativity of the fluorine atom and the strong mutual repulsion between the perfluoroalkyl groups, a more dense and delicate micro-convex structure is formed on the surface of the polymer , Can obtain the effect of super-hydrophobic structure, the contact angle can reach more than 150 °.

(2) When the N atom in the monomer is connected to an alkyl or fluoroalkyl group with a hydrophobic structure, even if the perfluoroalkyl carbon chain length is less than 6, the hydrophobic effect of the coating can still reach more than 120°;

(3) The use of plasma technology to prepare a nanometer-thick acrylic amide coating, compared with the use of brush coating and other existing technologies to prepare a coating with a thickness of tens of microns, can be achieved under the condition of reducing the amount of coating materials The protective effect is reduced, and the cost of product protective treatment is reduced.

(4) The thickness of the coating prepared by the method of the present application is uniform, and there is no problem of different hydrophobic effects in different parts of the coating, and the formed coating has excellent acid and alkali resistance.

In this application, monomer 2 alone can achieve an excellent hydrophobic coating effect; when monomer 1 is used alone and the group to which the N atom is attached has poor hydrophobicity, the obtained coating has poor hydrophobic performance. It is preferable to use monomer 1 and monomer 2 with two perfluoroalkyl groups attached to the N atom at the same time to form a hydrophobic coating. Compared with the use of a single monomer to form a hydrophobic coating, the water contact angle can be increased to 150°. Achieve super-hydrophobic effect.

Example 1

An acrylamide nano-coating and its preparation method go through the following steps:

(1) Place a 5cm×5cm metal aluminum block in the 100L plasma vacuum reaction chamber, and continuously evacuate the reaction chamber to make the vacuum degree reach 0.1 millitorr.

(2) Introduce helium gas with a flow rate of 100 sccm. Turn on the radio frequency plasma discharge to pretreat the aluminum metal block (that is, turn on the radio frequency mode pretreatment plasma discharge). The discharge power in the pretreatment stage is 80W, and the discharge continues 100s.

(3) Then, after the monomer 1a is passed, the monomer 2a is then introduced, and chemical vapor deposition is performed on the surface of the substrate to prepare a nano-coating. During the preparation of the coating, the flow rate of both monomers was 150 μL/min, and the introduction time was 600 s and 400 s, respectively. The plasma discharge for pretreatment is adjusted to the plasma discharge for deposition. The plasma in the deposition stage is generated by radio frequency discharge, the output mode is pulse, the pulse width is 2 μs, the repetition frequency is 1000 Hz, the discharge power is 50 W, and the discharge time is 1000 s.

(4) After the preparation of the coating is completed, nitrogen gas is introduced to restore the reaction chamber to normal pressure, the chamber is opened, and the metal aluminum block is taken out.

(5) Test the protective properties of the sample coating, including the thickness of the coating, hydrophobicity (water contact angle), and chemical resistance.

Monomer 1a

Monomer 2a

Among them, the device for generating plasma discharge for pretreatment and the device for generating plasma discharge for coating deposition may be one set or two separate devices. The plasma discharge device (for example, electrode) for pretreatment is preferably provided in the reaction chamber and around the base material, so as to facilitate quick connection with the coating process after pretreatment; and the plasma discharge device for deposition can be arranged in the reaction chamber It is arranged outside and away from the reaction chamber, so as to selectively or as far as possible avoid the negative influence of the plasma discharge on the substrate during the coating process.

Example 2

An acrylamide nano-coating and its preparation method go through the following steps:

(1) Place the PCB of the electronic watch in a 1000L plasma vacuum reaction chamber, and continuously evacuate the reaction chamber to achieve a vacuum of 10 mtorr.

(2) Introduce argon gas with a flow rate of 200 sccm. Turn on the RF plasma discharge to pretreat the PCB of the electronic watch (that is, turn on the RF mode pretreatment plasma discharge). The pretreatment plasma discharge power is 500W for continuous Discharge for 100s.

(3) Introduce monomer 1b, and then inject monomer 2b after the end, and perform chemical vapor deposition on the surface of the substrate to prepare nano-coating.

During the preparation of the coating, the flow rate of the two monomers was 150 μL/min, and the introduction time was 1000 s and 1600 s, respectively. The plasma discharge for pretreatment is adjusted to the plasma discharge for deposition.

The plasma in the deposition stage is generated by radio frequency discharge, the output mode is pulse, the pulse width is 10μs, the repetition frequency is 3000Hz, the discharge power is 90W, and the discharge time is 2600s.

(4) After the coating preparation is completed, nitrogen gas is introduced to restore the reaction chamber to normal pressure, the chamber is opened, and the PCB board is taken out.

(5) Test the protective properties of the sample coating, including the thickness of the coating, hydrophobicity (water contact angle), and chemical resistance.

Monomer 1b

Monomer 2b

Example 3

An acrylamide nano-coating and its preparation method go through the following steps:

(1) Place the magnesium alloy in the 4000L plasma vacuum reaction chamber, and continuously evacuate the reaction chamber to achieve a vacuum of 100 mTorr.

(2) Introduce argon gas with a flow rate of 200 sccm, turn on the radio frequency plasma discharge to pretreat the magnesium alloy substrate (that is, turn on the radio frequency mode pretreatment plasma discharge), the discharge power in the pretreatment stage is 150W, and the discharge continues for 100s .

(3) The monomer 1c and the monomer 2c are simultaneously introduced, and chemical vapor deposition is performed on the surface of the substrate to prepare a nano-coating. During the preparation of the coating, the flow rate of both monomers was 170 μL/min, and the introduction time was 1800 s. The plasma discharge for pretreatment is adjusted to the plasma discharge for deposition.

The plasma in the deposition stage is generated by radio frequency discharge, the output mode is pulse, the pulse width is 5μs, the repetition frequency is 2000Hz, the discharge power is 170W, and the discharge time is 3600s.

(4) After the coating preparation is completed, nitrogen gas is introduced to restore the reaction chamber to normal pressure, the chamber is opened, and the magnesium alloy is taken out.

(5) Test the protective properties of the sample coating, including the thickness of the coating, hydrophobicity (water contact angle), and chemical resistance.

Monomer 1c

Monomer 2c

Example 4

This embodiment is basically the same as Embodiment 1, except that:

Change Monomer 1a to Monomer 1d, Monomer 2a to Monomer 2d, and change the entry time of step (3) to 1600s and 1800s, and the discharge time to 3400s. The remaining parameters are the same.

Monomer 1d

Monolithic 2d

Example 5

This embodiment is basically the same as Embodiment 2 except for:

Change monomer 1a to monomer 1e and monomer 2a to monomer 2e. Change the access time of step (3) to 1600s and 2100s, and the discharge time to 3700s. The remaining parameters are the same.

Monomer 1e

Monomer 2e

Example 6

Compared with Example 1, the pulse width of the deposition stage is set to 500 μs, and the remaining parameters are the same.

Example 7

Compared with Example 2, the repetition frequency of the deposition stage is set to 300 Hz, and the remaining parameters are the same.

Example 8

Compared with Example 3, the discharge power in the pretreatment stage of step (2) is set to 300 W, and the remaining parameters are the same.

Example 9

Compared with Example 1, only the monomer 1a is passed in, the passing time is 1000s, and the remaining parameters are the same.

Example 10

Compared with Example 1, only monomer 1b is passed in, the passing time is 1000s, and the remaining parameters are the same.

Example 11

Compared with Example 2, only the monomer 2b is passed in, the passing time is 2600s, and the remaining parameters are the same.

Example 12

Compared with Example 2, the monomer 1b is replaced with 1e, and the monomer 2b is replaced with 2e, and the remaining parameters are the same.

Example 13

Compared with Example 2, the substrate PCB is replaced with an automobile rearview mirror, and other parameters are the same.

Example 14

Compared with Example 2, the substrate PCB is replaced with cloth, and other parameters are the same.

Example 15

Compared with Example 2, the substrate PCB is replaced with a speaker sound transmission network, and other parameters are the same.

The substrates after plating in the above embodiments were tested for coating thickness, water contact angle, and acid and alkali resistance.

The thickness of the nano-coating is tested using the US Filmetrics F20-UV-thickness film thickness measuring instrument.

Nano-coating water contact angle, tested according to GB/T 30447-2013 standard.

Acid resistance, alkali resistance corrosion, refer to GB1763-79 (89) paint film chemical resistance test method standard test.

Table 1

Note: Since Examples 13, 14, and 15 are all non-metallic, no acid resistance and alkali resistance tests were conducted.

The nano-coating is prepared by adopting the invention, and the thickness of the coating is very thin, which belongs to the nanometer scale; no organic solvent, curing agent and other contaminants are used in the preparation process; selecting a suitable monomer to prepare the nano-composite coating can obtain super-hydrophobic effect. Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements do not deviate from the essence of the corresponding technical solutions of the technical solutions of the embodiments of the present invention. range.

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Claims (15)

An acrylamide nano-coating, characterized in that the substrate is exposed to a monomer vapor atmosphere, and a chemical reaction occurs on the surface of the substrate by plasma discharge to form a protective coating; the monomer vapor is vaporized monomer 1 Or monomer 2, or a mixture of monomer 1 and monomer 2; the monomer 1 has the structure represented by the following formula (I); the monomer 2 has the structure represented by the following formula (II); monomer 1:

(I) Monomer 2:

(II) wherein R ¹ , R ² , R ³ , R ⁶ , R ⁷ and R ^{8 are} independently selected from hydrogen, alkyl, aryl, halogen, haloalkyl, alkenyl or haloalkenyl, X, Y Is hydrogen or halogen;

R ⁴ and R ^{5 are} independently selected from hydrogen, alkyl, aryl, halogen, haloalkyl or have the structure represented by formula (III): (III) R ¹¹ is a straight chain with 1 to 15 carbon atoms or contains branched chains Alkylene subunits, R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ are independently selected from hydrogen, alkyl, aryl, halogen or haloalkyl; R ⁹ and R ^{10 are} independently selected from 1-15 carbon atoms Straight chain, branched alkyl group or aryl group; or R ⁹ and R ¹⁰ are connected bonds; m, n, p, and q are integers from 0 to 20, but m and n are not simultaneously 0, p and q are not 0 at the same time. The acrylamide nano-coating according to item 1 of the patent application range, characterized in that R ¹ , R ² , R ³ , R ⁶ , R ⁷ and R ^{8 are} independently selected from hydrogen, methyl or fluorine groups, X and Y are fluorine. The acrylamide nanocoating according to item 1 of the patent application range, wherein R ⁹ and R ^{10 are} independently selected from linear alkylene groups having 1 to 5 carbon atoms. The acrylamide nano-coating according to item 1 of the patent application range, wherein R ¹¹ is a linear alkane subunit having 3 to 10 carbon atoms. The acrylamide nano-coating according to item 1 of the patent application range is characterized in that m and n are integers of 2-10. The acrylamide nano-coating according to item 1 of the patent application range is characterized in that the substrate is metal, optical instrument, clothing fabric, electronic device or medical device. A method for preparing acrylamide nano-coatings according to any one of claims 1 to 6 is characterized by the following steps: (1) Place the substrate in the reaction chamber of the plasma chamber, and evacuate the vacuum in the reaction chamber to 0.1-1000 mTorr; (2) Inject the plasma source gas, start the plasma discharge for deposition, and vaporize the monomer 1 and/or monomer 2 into the reaction chamber for chemical vapor deposition reaction; (3) Turn off the plasma discharge for deposition, pass clean compressed air or inert gas to return to normal pressure, open the cavity, and remove the substrate. The method for preparing acrylamide nano-coating according to item 7 of the patent application range is characterized in that, in step (2), the monomer 1 and the monomer 2 are respectively led into a vacuum chamber; Or, the monomer 1 and the monomer 2 are simultaneously led into the vacuum chamber; Alternatively, the monomer 1 or the monomer 2 is first introduced into the vacuum chamber, and then the mixed steam of the monomer 1 and the monomer 2 is simultaneously introduced. The preparation method of acrylamide nano-coating according to item 7 of the patent application range, characterized in that, in step (2), the plasma source gas is one or more of helium, argon, nitrogen and hydrogen mixture. According to the method for preparing acrylamide nano-coating described in item 7 of the patent application range, characterized in that the volume of the plasma chamber is 1L-5000 L; The plasma source gas flow rate is 5-1000 sccm; The flow rate of the monomer vapor is 1-2000 μL/min. The method for preparing acrylamide nano-coating according to item 7 of the patent application range, characterized in that, in the step (2), after the plasma source gas is passed in and the deposition plasma is discharged Previously, it also included a plasma discharge process for pretreatment of the substrate. The preparation method of the acrylamide nano-coating according to item 11 of the patent application range is characterized in that the power of the plasma discharge for pretreatment is 2-500 W, and the continuous discharge time is 1-3600 s. The method for preparing acrylamide nano-coating according to item 7 of the patent application range is characterized in that, in the step (2), the power of the plasma discharge for deposition is 2-500 W, and the continuous discharge time is 600 -20000s. The preparation method of acrylamide nano-coating according to item 7 or item 11 of the patent application range, characterized in that the plasma discharge method is radio frequency discharge, microwave discharge, intermediate frequency discharge, penning discharge or electric spark Discharge. The method for preparing acrylamide nano-coating according to item 7 or item 11 of the patent application range is characterized in that the plasma discharge method is radio frequency discharge, and the plasma radio frequency energy output method during radio frequency discharge is: Pulse or continuous output, when the plasma radio frequency energy output mode is pulse output, the pulse width is 10μs-50ms, and the repetition frequency is 20Hz-10kHz.