Self-repairable super-hydrophilic coating and preparation method and application thereof

Abstract

The application belongs to the technical field of super-hydrophilic coating, and particularly relates to a self-repairable super-hydrophilic coating, a preparation method and application thereof.The self-repairable super-hydrophilic coating comprises the following components in parts by weight: 10-20 parts of epoxy resin, 1-5 parts of curing agent, 10-150 parts of solvent, 0-7 parts of nano filler, 5-15 parts of modifier and a hydrophilic component dissolved in another solvent.The super-hydrophilic coating has excellent oil pollution prevention characteristics, and can have antibacterial, scale inhibition and drag reduction characteristics, and can be applied to the fields of oil adhesion prevention, microbial adhesion prevention, underwater drag reduction, oil-water separation and the like, can effectively resist conventional organic oil phase pollution, even high-viscosity crude oil pollution, and can be repaired in water, strong acid, strong base, high salt and artificial seawater, solving the problem that the existing super-hydrophilic coating cannot be repaired in an extreme underwater environment.

Description

Technical Field

[0001] This invention belongs to the field of superhydrophilic coating technology, specifically relating to a self-healing superhydrophilic coating, its preparation method, and its application. Technical Background

[0002] Superhydrophilic coatings, as unique surfaces with extreme wettability, have broad application prospects in self-cleaning, drag reduction, anti-fogging, and oil-water separation. Inspired by nature, biomimetic superhydrophilic coatings such as superhydrophilic coatings and superhydrophilic elastomers have been successfully prepared by designing surface chemical compositions and constructing micro-nano rough structures. However, superhydrophilic coatings are susceptible to environmental influences, leading to the loss of chemical components or external damage, forming defects such as fine cracks and fractures. This results in a decrease in surface hydrophilicity, significantly affecting their service life and even posing safety hazards. Therefore, repairing structural damage to superhydrophilic coatings is extremely important.

[0003] While in-situ compensation, re-biomineralization processes, and self-polishing techniques can restore the wettability of superhydrophilic coatings and address surface compositional damage, compositional repair cannot solve the problem of structural damage. Utilizing the reversibility of dynamic chemical bonds such as hydrogen bonding, electrostatic effects, and boron-ester bonds can effectively repair surface structural damage. However, under prolonged underwater conditions, these reversible dynamic bonds, such as hydrogen bonding and boron-ester bonds, are easily affected by external factors like water molecules and ions. This weakens or even eliminates the self-healing ability of the superhydrophilic coating, making it unable to effectively repair damaged surface structures. Therefore, achieving stable repair of superhydrophilic coatings in extreme underwater environments remains a pressing challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a self-healing superhydrophilic coating, its preparation method, and its applications. This self-healing superhydrophilic coating can repair surface structural damage and restore the surface's superhydrophilic state in situ in extreme underwater environments, such as solutions containing water, strong acids, strong alkalis, high-concentration salts, and artificial seawater. Through in-situ heating, pressing, and other methods, structural damage such as cracks can be repaired, restoring surface wettability. This achieves structural damage repair of the superhydrophilic coating in extreme underwater environments.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] This invention provides a self-healing superhydrophilic coating, comprising the following components by weight:

[0007] The composition consists of 10-20 parts epoxy resin, 1-5 parts curing agent, 10-150 parts solvent, 0-7 parts nanofiller, 5-15 parts modifier, and a hydrophilic component dissolved in another solvent.

[0008] Furthermore, the epoxy resin is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin.

[0009] Furthermore, the curing agent is an amine curing agent or an amine-modified cashew nut phenol curing agent.

[0010] Furthermore, the solvent is any one of organic solvents including ethyl acetate, ethanol, acetone, tetrahydrofuran, N'N-dimethylformamide, N'N-dimethylacetamide, or dimethyl sulfoxide.

[0011] Furthermore, the nanofiller is one of silicon dioxide, titanium dioxide, iron oxide, montmorillonite, attapulgite, sepiolite, carbon nanotubes, graphene oxide, and boron nitride.

[0012] Furthermore, the modifier is any one or more of fatty amines, alkyl thiols, fatty alcohols, and fatty acids.

[0013] Furthermore, the hydrophilic component dissolved in another solvent is 10-500 parts of the hydrophilic component dissolved in another solvent, wherein the other solvent is any one of ethanol, acetone, and methanol, and the hydrophilic component is at least one of polyethyleneimine, glycidyltrimethylammonium chloride, polyaniline, silica, silver nanoparticles, iron tetroxide, montmorillonite, attapulgite, sepiolite, and graphene oxide.

[0014] The present invention also provides a method for preparing the superhydrophilic coating, comprising the following steps:

[0015] (1) Mix epoxy resin, curing agent, nanofiller and modifier evenly, and apply to the substrate surface by scraping or spraying;

[0016] (2) The hydrophilic components dissolved and dispersed in the solvent are sprayed onto the surface of the epoxy resin layer, and the superhydrophilic coating is obtained after the reaction.

[0017] Furthermore, in step (1), the mixing is performed using ultrasonic treatment, and the reaction temperature is 20-80℃; in step (2), the reaction temperature is 20-80℃, and the reaction time is 0.5-24h.

[0018] The present invention also provides an application of the superhydrophilic coating in extreme underwater environments, wherein the superhydrophilic coating is capable of self-healing in extreme underwater environments.

[0019] Extreme underwater environments refer to water, strong acids, strong alkalis, high salinity, and artificial seawater. Repair methods refer to heating or pressure-based repairs; heating methods include hot air, hot water, photothermal heating, and magnetothermal heating.

[0020] The beneficial effects of this invention are as follows:

[0021] The superhydrophilic coating provided by this invention possesses excellent oil-repellent properties and also exhibits antibacterial, scale-inhibiting, and drag-reducing characteristics. It can be applied to fields such as oil adhesion prevention, microbial adhesion prevention, underwater drag reduction, and oil-water separation. It can effectively resist conventional organic oil phase contamination, and even high-viscosity crude oil contamination. Furthermore, it can be repaired in water, strong acids, strong alkalis, high salinity, and artificial seawater, solving the problem of existing superhydrophilic coatings being unable to be repaired in extreme underwater environments. The superior performance of the prepared superhydrophilic coating is mainly attributed to the following reasons: 1. Chemical stability in water, strong acids, strong alkalis, high salinity, and artificial seawater; 2. Excellent hydrophilicity, antibacterial, scale-inhibiting, and underwater drag-reducing properties of the hydrophilic layer; 3. Stable repairability of the epoxy resin layer. Detailed Implementation

[0022] This invention provides a superhydrophilic coating, comprising the following components by weight:

[0023] 10-20 parts epoxy resin, 1-5 parts curing agent, 10-150 parts solvent and 0-7 parts nanofiller;

[0024] 5-15 parts of at least one of fatty amines, alkyl thiols, fatty alcohols, and fatty acids;

[0025] It also includes at least one of the following hydrophilic components dissolved in 10-500 parts of solvent: polyethyleneimine (PEI), glycidyltrimethylammonium chloride, polyaniline, silica, silver (Ag) nanoparticles, iron oxide, montmorillonite, attapulgite, sepiolite, and graphene oxide.

[0026] In this invention, the superhydrophilic coating can repair surface structural damage and restore surface superhydrophilicity in water, acidic solutions, alkaline solutions, salt solutions, and seawater through heating, pressing, or other methods. Preferably, it is applied to the substrate surface by scraping or spraying.

[0027] The acidic solution is preferably one or a mixture of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, etc.; the alkaline solution is preferably one or a mixture of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, etc.; and the salt solution is one or a mixture of sodium chloride, magnesium chloride, lithium chloride, aluminum chloride, sodium sulfate, magnesium sulfate, ferric chloride, ferric sulfate, etc.

[0028] In this invention, the epoxy resin is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin, wherein the bisphenol A type epoxy resin is preferably an E42 epoxy resin or an E44 epoxy resin, and the bisphenol F type epoxy resin is preferably an F51 epoxy resin.

[0029] In this invention, the curing agent is an amine curing agent or an amine-modified cashew nut shell curing agent, wherein the amine curing agent is preferably one of polyetheramine, m-phenylenediamine and octyldiamine.

[0030] In this invention, the solvent is an organic solvent such as ethyl acetate, ethanol, acetone, tetrahydrofuran, N'N-dimethylformamide, N'N-dimethylacetamide, or dimethyl sulfoxide.

[0031] In this invention, the fatty amine is one of octadecylamine, tetradecylamine, dodecylamine, decylamine, and octylamine.

[0032] In this invention, the alkyl thiol is one of dodecyl thiol, undecyl thiol, and octadecyl thiol.

[0033] In this invention, the fatty alcohol is one of undecyl alcohol, dodecanol, and octanol.

[0034] In this invention, the fatty acid is one of lauric acid, caprylic acid and stearic acid.

[0035] In this invention, the nanofiller is one of silicon dioxide, titanium dioxide, iron oxide, montmorillonite, attapulgite, sepiolite, carbon nanotubes, graphene oxide, and boron nitride.

[0036] In this invention, the solvent for dissolving the hydrophilic components is ethanol, acetone, or methanol.

[0037] In this invention, the hydrophilic component is at least one of polyethyleneimine (PEI), glycidyltrimethylammonium chloride, polyaniline, silicon dioxide, silver (Ag) nanoparticles, iron tetroxide, montmorillonite, attapulgite, sepiolite, and graphene oxide.

[0038] On the other hand, the present invention also provides a method for preparing the above-mentioned superhydrophilic coating, comprising the following steps:

[0039] Epoxy resin, curing agent, nanofiller, and at least one of fatty amines, alkyl thiols, fatty alcohols, and fatty acids are mixed uniformly (preferably by ultrasonic mixing) and then coated or sprayed onto the substrate surface, wherein the reaction temperature is 20–80°C. Then, the hydrophilic component dissolved and dispersed in a solvent is sprayed onto the epoxy resin layer surface. After the reaction, a self-healing superhydrophilic coating capable of operating in extreme underwater environments is obtained, wherein the reaction temperature is preferably 20–80°C, and the reaction time is preferably 0.5–24 hours.

[0040] The following experimental examples and embodiments are used to further illustrate the present invention, but are not limited to the present invention.

[0041] Example 1

[0042] 20 parts of E44 epoxy resin and 4 parts of cashew nut shell phenol modified curing agent were weighed, 10 parts of decylamine and 2 parts of carbon nanotubes were added, and the mixture was dissolved and dispersed in 20 parts of ethyl acetate solution. After ultrasonic mixing, the mixture was scraped onto the substrate surface to obtain an epoxy resin-coated surface at 70℃. Then, 1.5 parts of PEI and 2.7 parts of glycidyltrimethylammonium chloride were dissolved and dispersed in 15 parts of ethanol and sprayed onto the above surface, and reacted at 80℃ for 5 hours. The prepared superhydrophilic coating can repair scratches and restore surface hydrophilicity in water, 1.0M sulfuric acid, 1.0M sodium hydroxide, and 1.0M sodium chloride, with an underwater oil contact angle of 152°. In addition, the coating surface can effectively kill E. coli, with an underwater friction coefficient of only 0.03, and after a 10-hour scaling test, the maximum scaling amount on the surface was 0.45 mg / cm³. 2 .

[0043] Example 2

[0044] Weigh 20 parts of E44 epoxy resin and 5 parts of polyetheramine curing agent, add 15 parts of decylamine, dissolve and disperse in 150 parts of ethyl acetate solution, ultrasonically mix evenly, and spray onto the substrate surface to obtain an epoxy resin-coated surface at 65℃. Then, dissolve and disperse 15 parts of PEI in 100 parts of ethanol, spray onto the above surface, and react at 70℃ for 6 hours. The prepared superhydrophilic coating can repair scratches and restore surface hydrophilicity in water, 1.0M sulfuric acid, 1.0M sodium hydroxide, and 1.0M sodium chloride, with an underwater oil contact angle of 158°. In addition, the underwater friction coefficient of the coating is only 0.02, and the maximum scaling amount is 0.82 mg / cm³. 2 .

[0045] Example 3

[0046] Weigh 20 parts of E44 epoxy resin and 5 parts of cashew phenol modified curing agent, add 15 parts of octadecylamine, dissolve and disperse in 150 parts of ethyl acetate solution, ultrasonically mix evenly, and spray onto the substrate surface to obtain an epoxy resin coated surface at 70℃. Then, dissolve and disperse 7.5 parts of PEI and 10 parts of glycidyltrimethylammonium chloride in 80 parts of methanol, spray onto the above surface, and react at 70℃ for 6 hours. The prepared superhydrophilic coating can repair scratches and restore surface hydrophilicity in water, 1.0M sulfuric acid, 1.0M sodium hydroxide, and 1.0M sodium chloride, with an underwater oil contact angle of 157°. In addition, the coating surface can effectively kill E. coli, with an underwater friction coefficient of only 0.021 and a maximum scaling amount of 0.42 mg / cm³. 2 .

[0047] Example 4

[0048] 20 parts of E44 epoxy resin and 4 parts of m-phenylenediamine curing agent were weighed, and 10 parts of dodecylamine were added. The mixture was then dissolved and dispersed in 20 parts of ethyl acetate solution. After ultrasonic mixing, the solution was scraped onto the substrate surface to obtain an epoxy resin-coated surface at 70℃. Next, 6 parts of PEI and 3 parts of silver (Ag) nanoparticles were dissolved and dispersed in 80 parts of ethanol solution and sprayed onto the above surface. The mixture was then reacted at 70℃ for 7 hours. The prepared superhydrophilic coating can repair scratches and restore surface hydrophilicity in water, 1.0M sulfuric acid, 1.0M sodium hydroxide, and 1.0M sodium chloride, with an underwater oil contact angle of 151°. Furthermore, the coating surface can effectively kill E. coli, with an underwater friction coefficient of only 0.05 and a maximum scaling amount of 0.90 mg / cm³. 2 .

[0049] Example 5

[0050] Weigh 20 parts of E44 epoxy resin and 5 parts of octyldiamine curing agent, add 10 parts of octylamine, dissolve and disperse in 150 parts of ethyl acetate solution, ultrasonically mix evenly, and spray onto the substrate surface to obtain an epoxy resin-coated surface at 70℃. Then, dissolve and disperse 2 parts of polyaniline and 3 parts of glycidyltrimethylammonium chloride in 20 parts of ethanol solution, spray onto the above surface, and react at 80℃ for 10 hours. The prepared superhydrophilic coating can repair scratches and restore surface hydrophilicity in water, 1.0M sulfuric acid, 1.0M sodium hydroxide, and 1.0M sodium chloride, with an underwater oil contact angle of 153°. In addition, the coating surface can effectively kill E. coli, with an underwater friction coefficient of only 0.03 and a maximum scaling amount of 0.55 mg / cm³. 2 .

[0051] The self-healing properties of the superhydrophilic coatings in Examples 1-5 in different underwater environments are shown in Table 1.

[0052] Table 1. Self-healing properties of the superhydrophilic coatings in Examples 1-5 in different underwater environments.

[0053]

[0054]

[0055] Note: 1. The concentrations of H2SO4, NaOH, and NaCl are all 1.0 M;

[0056] 2. The aforementioned This indicates that it has good self-healing properties in the corresponding solution environment.

[0057] Example 6

[0058] 20 parts of E44 epoxy resin and 2.8 parts of m-phenylenediamine were weighed, 8.5 parts of decylamine and 1 part of titanium dioxide were added, and the mixture was ultrasonically mixed for 20 minutes. The mixture was then reacted at 80℃ for 14 hours to obtain a small-molecule underwater adhesive. The prepared adhesive was coated onto a steel plate surface at a concentration of 5 mg / mL, and its bonding performance in 1.0 M NaOH reached a maximum of 14 MPa. After recycling, the adhesive performance was retested, and the maximum bonding performance still reached 13.5 MPa, demonstrating excellent recyclability.

[0059] Example 7

[0060] 20 parts of E44 epoxy resin and 2.8 parts of octyldiamine were weighed, 6 parts of octylamine and 0.2 parts of montmorillonite were added, and the mixture was ultrasonically mixed for 20 minutes. The mixture was then reacted at 80℃ for 10 hours to obtain a small-molecule underwater adhesive. The prepared adhesive was coated onto a steel plate surface at a concentration of 6 mg / mL, and its bonding performance in 1.0 M NaCl reached a maximum of 14.8 MPa. After recycling, the adhesive performance was retested, and the maximum bonding performance still reached 14.7 MPa, demonstrating excellent recyclability.

[0061] Example 8

[0062] Ten parts of E44 epoxy resin and 2.5 parts of cashew nut shell phenol modified curing agent were weighed, and 7 parts of dodecylamine were added. No nanoparticles were added. The mixture was ultrasonically mixed for 20 minutes, and then reacted at 80℃ for 12 hours to obtain a small-molecule underwater adhesive. The prepared adhesive was coated onto a steel plate surface at a concentration of 6 mg / mL. Its bonding performance in 1.0 M H₂SO₄ reached a maximum of 5 MPa. After recycling, the adhesive performance was retested, and the maximum bonding performance still reached 4.8 MPa, demonstrating excellent recyclability.

[0063] Example 9

[0064] Weigh 20 parts of E44 epoxy resin and 2.5 parts of cashew nut shell phenol modified curing agent, add 15 parts of octadecylamine and 7 parts of titanium dioxide, ultrasonically mix for 20 minutes, and then react at 80℃ for 8 hours to obtain a small molecule underwater adhesive. The prepared adhesive was coated onto a steel plate surface at a concentration of 8 mg / mL, and its bonding performance in 1.0 M H₂SO₄ reached a maximum of 3 MPa. After recycling, the adhesive performance was retested, and the maximum bonding performance still reached 3 MPa, demonstrating excellent recyclability.

[0065] Example 10

[0066] Ten parts of E44 epoxy resin and one part of cashew nut shell phenol modified curing agent were weighed, and five parts of octylamine and 0.2 parts of titanium dioxide were added. The mixture was ultrasonically mixed for 20 minutes and then reacted at 80°C for 12 hours to obtain a small-molecule underwater adhesive. The prepared adhesive was coated onto a steel plate surface at a concentration of 7 mg / mL, and its adhesion performance in water reached a maximum of 10 MPa. After recycling, the adhesive performance was retested, and the maximum adhesion performance still reached 9.7 MPa, demonstrating excellent recyclability.

[0067] Example 11

[0068] Weigh 20 parts of E44 epoxy resin and 5 parts of cashew nut shell phenol modified curing agent, add 15 parts of tetradecylamine and 3 parts of titanium dioxide, ultrasonically mix for 20 minutes, and then react at 80℃ for 12 hours to obtain a small molecule underwater adhesive. The prepared adhesive was coated onto a steel plate surface at a concentration of 0.8 mg / mL, and its bonding performance in seawater reached a maximum of 5 MPa. After recycling, the adhesive performance was retested, and the maximum bonding performance still reached 5 MPa, demonstrating excellent recyclability.

[0069] The highest bonding performance and recyclability of the adhesives in Examples 1 and 6-10 in different underwater environments are shown in Table 1. The bonding performance tested in Examples 1 and 6-10 and Comparative Example 3 below are all lap shear performance.

[0070] Table 2. Maximum bonding performance and recyclability of the adhesives in Examples 1 and 6-10 in different underwater environments.

[0071]

[0072]

[0073] Note: The concentrations of H2SO4, NaOH, and NaCl are all 1.0M.

[0074] Comparative Example 1

[0075] Weigh 20 parts of E44 epoxy resin and 4 parts of cashew nut shell phenol modified curing agent, add 2 parts of carbon nanotubes, dissolve and disperse in 20 parts of ethyl acetate solution, ultrasonically mix evenly, and then coat onto the substrate surface to obtain an epoxy resin coated surface at 70℃. Then react at 80℃ for 5 hours. The prepared product cannot repair scratches in water, 1.0M sulfuric acid, 1.0M sodium hydroxide, and 1.0M sodium chloride, and water droplets cannot spread completely on the surface, meaning the surface does not have superhydrophilicity.

[0076] Comparative Example 2

[0077] Weigh 20 parts of E44 epoxy resin and 5 parts of cashew nut shell phenol modified curing agent, dissolve and disperse them in 150 parts of ethyl acetate solution, ultrasonically mix evenly, and then spray onto the substrate surface to obtain an epoxy resin coated surface. Then react at 80℃ for 12 hours. The prepared coating cannot repair scratches in water, 1.0M sulfuric acid, 1.0M sodium hydroxide, and 1.0M sodium chloride, and water droplets cannot spread completely on the surface, that is, the surface does not have superhydrophilicity.

[0078] Comparative Example 3

[0079] Weigh 20 parts of E44 epoxy resin and 5 parts of cashew phenol modified curing agent, mix ultrasonically for 20 minutes, and then react at 80°C for 12 hours. The prepared product has no adhesive properties and cannot be coated onto the surface of the steel plate.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A self-healing superhydrophilic coating, characterized in that, By weight, it includes the following components: The composition consists of 10-20 parts epoxy resin, 1-5 parts curing agent, 10-150 parts solvent, 0-7 parts nanofiller, 5-15 parts modifier, and a hydrophilic component dissolved in another solvent. The epoxy resin is bisphenol A type epoxy resin or bisphenol F type epoxy resin; The curing agent is polyetheramine, m-phenylenediamine, octyldiamine, or amino-modified cashew nut phenol curing agent; The modifier is any one of octadecylamine, tetradecylamine, dodecylamine, and decylamine; The hydrophilic composition dissolved in another solvent is 10-500 parts of the other solvent dissolved in 1-50 parts of the hydrophilic composition, wherein the other solvent is any one of ethanol, acetone, and methanol, and the hydrophilic composition is polyethyleneimine, or polyethyleneimine and glycidyltrimethylammonium chloride, or polyethyleneimine and silver nanoparticles. The method for preparing the superhydrophilic coating includes the following steps: (1) Mix epoxy resin, curing agent, nanofiller, modifier and solvent evenly, and apply to the substrate surface by scraping or spraying; (2) The hydrophilic component dissolved and dispersed in another solvent is sprayed onto the surface of the epoxy resin layer, and the superhydrophilic coating is obtained after the reaction.

2. The superhydrophilic coating according to claim 1, characterized in that, The solvent is any one of ethyl acetate, ethanol, acetone, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, or dimethyl sulfoxide.

3. The superhydrophilic coating according to claim 1, characterized in that, The nanofiller is one of the following: silicon dioxide, titanium dioxide, iron oxide, montmorillonite, attapulgite, sepiolite, carbon nanotubes, graphene oxide, and boron nitride.

4. The superhydrophilic coating as described in claim 1, characterized in that, In step (1), the mixing is performed by ultrasonic treatment and the reaction temperature is 20-80℃; in step (2), the reaction temperature is 20-80℃ and the reaction time is 0.5-24h.

5. The application of the superhydrophilic coating as described in any one of claims 1-4 in extreme underwater environments, characterized in that, The superhydrophilic coating is capable of self-healing in extreme underwater environments.

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