Self-cleaning super-hydrophobic oleophobic glass cover plate and preparation method thereof

Abstract

The invention relates to the technical field of glass product processing, and provides a preparation method of a self-cleaning super-hydrophobic and oleophobic glass cover plate, which comprises the following steps: uniformly mixing zinc lactate, a fluorine-containing silane coupling agent and lactic acid, aging for a period of time, smearing the aged solution on the surface of the glass cover plate, carrying out heat treatment, and drying to obtain the self-cleaning super-hydrophobic and oleophobic glass cover plate. The stable and firm hybrid coating is formed on the surface of the glass cover plate, the glass cover plate obtained through the preparation method can have a good self-cleaning effect while being super-hydrophobic and oleophobic, the light transmittance of the glass cover plate is good, and the glass cover plate can be widely applied to the fields of electronic display screens and the like.

Description

Technical Field

[0001] This invention relates to the field of glass processing technology, and in particular to a self-cleaning superhydrophobic and oleophobic glass cover plate and its preparation method. Background Technology

[0002] In recent years, the widespread use of electronic products has led to higher demands on the self-cleaning ability of glass covers. People need glass covers to meet the requirements of light transmittance while allowing pollutants on the surface of the glass cover to degrade or fall off on their own under the influence of external conditions.

[0003] Currently, there are two main methods to achieve self-cleaning function on the surface of solid substrates. One method is to make the surface of the solid substrate hydrophobic, so that liquids form water droplets on the surface of the solid substrate, and the stains on the surface of the solid substrate can be wrapped on the surface of the rolling water droplets and carried away. The other method is to use materials such as titanium dioxide to generate free radicals under light, which decompose organic pollutants on the surface of the solid substrate into water and carbon dioxide. However, while decomposing organic pollutants, free radicals will also destroy the hydrophobic coating, which is also an organic material. The hydrophobicity of the solid substrate will decrease quickly, and naturally, the self-cleaning function will also decrease.

[0004] Although hydrophobic coatings are simple to prepare, controlling their roughness is very difficult. Higher roughness increases light reflection and reduces the coating's transmittance, while lower roughness significantly reduces the coating's hydrophobicity. In existing technologies, photocatalytic nanomaterials such as titanium dioxide are often used on the surface of glass covers to achieve photocatalytic effects. However, few technicians utilize these photocatalytic materials to form uniformly sized protrusions on the surface of glass covers, enabling them to possess both photocatalytic effects and improve the hydrophobicity and oleophobicity of the glass covers.

[0005] Therefore, there is an urgent need for a glass cover that combines self-cleaning and superhydrophobic / oleophobic properties to meet the needs of consumers. Summary of the Invention

[0006] To address the technical problems existing in the background art, this invention proposes a method for preparing a self-cleaning superhydrophobic and oleophobic glass cover, comprising the following steps: S1. Prepare solution I containing zinc lactate; S2. Prepare solution II containing fluorosilane coupling agent; S3. Mix solution I, solution II and lactic acid solution thoroughly and allow to age to obtain coating solution; S4. The coating liquid is placed on the glass surface and heat-treated to obtain a self-cleaning superhydrophobic and oleophobic glass cover.

[0007] In step S1, the concentration of the zinc lactate solution is 3-5 wt%.

[0008] In this invention, zinc lactate, as a stable and soluble complex, can prevent zinc ions from precipitating, facilitating its reaction with fluorinated silane coupling agents in subsequent steps.

[0009] In step S2, the concentration of the fluorinated silane coupling agent is 0.5-3 wt%.

[0010] In step S3, the volume ratio of solution I to solution II is 1:5-20.

[0011] In step S3, the aging temperature is 30-40℃ and the aging time is 1-2 hours.

[0012] In this invention, when solution I, solution II and lactic acid solution are mixed, the weak acidity provided by lactic acid can catalyze the hydrolysis reaction of the fluorinated silane coupling agent. The silanol groups generated by hydrolysis can either condense with each other to form a Si-O-Si network or interact with zinc ions in the zinc lactic acid complex. After aging, the resulting coating liquid forms a uniform and stable sol system.

[0013] In step S4, the heat treatment includes drying and annealing.

[0014] In step S4, the drying temperature is 50-90℃ and the drying time is 10-20 min.

[0015] In step S4, the annealing temperature is 180-220℃ and the annealing time is 50-100min.

[0016] In this invention, during the heat treatment, zinc lactate is converted into zinc oxide, silanol groups are completely condensed, some silanol groups condense with each other to form a three-dimensional cross-linked network, and some silanol groups form stable chemical bonds with the surface of the glass cover plate, ultimately forming a stable and firm hybrid coating on the surface of the glass cover plate.

[0017] The present invention also proposes a self-cleaning superhydrophobic and oleophobic glass cover, which is prepared by the above-described method.

[0018] Beneficial effects of this invention: (1) In this invention, a hybrid coating is superimposed on the glass cover plate. The hybrid coating is composed of zinc oxide protrusions and fluorine-containing substances. Zinc oxide can generate active free radicals under light conditions, decompose organic stains, and make the glass cover plate have a certain self-cleaning effect. The fluorine-containing substances and the protrusion structure make the glass surface have a certain anti-fingerprint and hydrophobic effect, preventing excessive accumulation of stains on the surface of the glass cover plate, which would lead to a decrease in self-cleaning ability. (2) In this invention, the hybrid coating is formed by heat treatment of zinc lactate and fluorine-containing substances. Compared with traditional technology, this method is not only simple and easy to operate, but also results in a hybrid coating with high bonding strength with the glass cover plate, which is not easy to fall off. (3) In this invention, although zinc oxide itself is a hydrophilic material, its microscopic protrusion structure and fluorine-containing coating overcome the hydrophilic properties of zinc oxide, and the resulting hybrid coating has both self-cleaning and superhydrophobic and oleophobic effects. Detailed Implementation

[0019] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0021] The technical solution of the present invention will now be described more clearly and completely with reference to specific embodiments and comparative examples.

[0022] Example 1 This embodiment proposes a self-cleaning superoleophobic and hydrophobic glass cover plate, the preparation method of which is shown below: (1) Take zinc acetate dihydrate and disperse it in anhydrous ethanol under stirring and ultrasonic conditions to obtain anhydrous ethanol solution of zinc acetate; add lactic acid aqueous solution dropwise to anhydrous ethanol solution of zinc acetate to ensure that lactic acid is in excess, and react at 40℃ for 1.5h to obtain transparent solution A (zinc lactate concentration is 3wt%, pH=3.2). (2) Dissolve perfluorooctyltriethoxysilane in another part of anhydrous ethanol to obtain a solution B with a concentration of 2wt%; (3) Under stirring conditions, solution A is slowly added to solution B. The volume ratio of solution A to solution B is 1:12. The acidity of solution A will promote the hydrolysis of the fluorinated silane coupling agent. The hydrolysate of the fluorinated silane coupling agent interacts with zinc ions. Let it stand for 1 hour to mature and form a uniform and stable coating liquid. (4) Apply the coating liquid to the glass surface (borosilicate glass), spin coat at 2000 rpm for 30s, then place it in an oven, and then dry it at 60℃ for 15min. After the surface is completely dry, anneal it at 200℃ for 80min. The coating is tightly bonded to the glass surface and forms a concave-convex structure on the glass surface. The protruding part is composed of zinc oxide, and the concave part is a fluorine-containing coating.

[0023] Optionally, lactic acid solution can also be added in step (3).

[0024] Example 2 This embodiment proposes a self-cleaning superoleophobic and hydrophobic glass cover plate, the preparation method of which is shown below: (1) Add the lactic acid aqueous solution dropwise to the anhydrous ethanol solution of zinc acetate, ensuring that the lactic acid is in excess, and react at 30°C for 2 hours to obtain a transparent solution A (zinc lactate concentration is 4wt%, pH=3.2). (2) Dissolve perfluorooctyltriethoxysilane in another part of anhydrous ethanol to obtain a solution B with a concentration of 3wt%; (3) Under stirring conditions, solution A is slowly added to solution B. The volume ratio of solution A to solution B is 1:5. The acidity of solution A will promote the hydrolysis of the fluorinated silane coupling agent. The hydrolysate of the fluorinated silane coupling agent interacts with zinc ions. Let it stand for 1 hour to mature and form a uniform and stable coating liquid. (4) Apply the coating liquid to the glass surface (borosilicate glass), spin coat at 2000 rpm for 30 seconds, then place it in an oven, and then dry it at 90°C for 10 minutes. After the surface is completely dry, anneal it at 180°C for 100 minutes. The coating is tightly bonded to the glass surface and forms a concave-convex structure on the glass surface. The protruding part is composed of zinc oxide, and the concave part is a fluorine-containing coating.

[0025] Example 3 This embodiment proposes a self-cleaning superoleophobic and hydrophobic glass cover plate, the preparation method of which is shown below: (1) Take zinc acetate dihydrate and disperse it in anhydrous ethanol under stirring and ultrasonic conditions to obtain anhydrous ethanol solution of zinc acetate; add lactic acid aqueous solution dropwise to anhydrous ethanol solution of zinc acetate to ensure that lactic acid is in excess, and react at 30°C for 3 hours to obtain transparent solution A (zinc lactate concentration is 5wt%, pH=3.2). (2) Dissolve perfluorooctyltriethoxysilane in another part of anhydrous ethanol to obtain a solution B with a concentration of 0.5%; (3) Under stirring conditions, solution A is slowly added to solution B. The volume ratio of solution A to solution B is 1:20. The acidity of solution A will promote the hydrolysis of the fluorinated silane coupling agent. The hydrolysate of the fluorinated silane coupling agent interacts with zinc ions. Let it stand for 1 hour to mature and form a uniform and stable coating liquid. (4) Apply the coating liquid to the glass surface (quartz glass), spin coat at 2000 rpm for 30s, then place it in an oven, and then dry it at 50℃ for 20min. After the surface is completely dry, anneal it at 220℃ for 50min. The coating is tightly bonded to the glass surface and forms a concave-convex structure on the glass surface. The protruding part is composed of zinc oxide, and the concave part is a fluorine-containing coating.

[0026] Example 4 This embodiment proposes a self-cleaning superoleophobic and hydrophobic glass cover plate, the preparation method of which is shown below: (1) Take zinc acetate dihydrate and disperse it in anhydrous ethanol under stirring and ultrasonic conditions to obtain anhydrous ethanol solution of zinc acetate; add lactic acid aqueous solution dropwise to anhydrous ethanol solution of zinc acetate to ensure that lactic acid is in excess, and react at 40℃ for 3.5h to obtain transparent solution A (zinc lactate concentration is 4wt%, pH=3.2). (2) Dissolve perfluorooctyltriethoxysilane in another part of anhydrous ethanol to obtain a solution B with a concentration of 1 wt%; (3) Under stirring conditions, solution A is slowly added to solution B. The volume ratio of solution A to solution B is 1:10. The acidity of solution A will promote the hydrolysis of the fluorinated silane coupling agent. The hydrolysate of the fluorinated silane coupling agent interacts with zinc ions. Let it stand for 1 hour to mature and form a uniform and stable coating liquid. (4) Apply the coating liquid to the glass surface (high aluminosilicate glass), spin coat at 2000 rpm for 30s, then place it in an oven, and then dry it at 80℃ for 15min. After the surface is completely dry, anneal it at 200℃ for 90min. The coating is tightly bonded to the glass surface and forms a concave-convex structure on the glass surface. The protruding part is composed of zinc oxide, and the concave part is a fluorine-containing coating. Comparative Example 1 This comparative example presents a glass cover plate, which is prepared in the same way as in Example 1, except that “solution A” in step (1) is replaced with “a mixed solution of zinc lactate water and ethanol of equal concentration”.

[0027] In Comparative Example 1, although the zinc lactate solution can provide zinc ions, it cannot provide sufficient acidity, and no additional lactic acid is added in subsequent step (3) to promote the hydrolysis of the subsequent fluorinated silane coupling agent and the formation of zinc oxide. As a result, the hybrid coating obtained is significantly reduced. Comparative Example 2 This comparative example presents a glass cover plate, which is prepared in the same way as in Example 1, except that “solution A” in step (1) is replaced with “a mixed solution of lactic acid water and ethanol of equal concentration”.

[0028] In Comparative Example 2, solution A contained only lactic acid and no zinc ions. The resulting glass cover surface was relatively flat and had no zinc oxide protrusions. The hydrophobic and oleophobic properties could only be provided by the fluorine-containing coating. In addition, the coating in Comparative Example 2 lacked the catalytic degradation function of zinc oxide, and its performance was significantly lower than that of Example 1. Comparative Example 3 This comparative example presents a glass cover plate, which is prepared in the same way as in Example 1, except that “solution B” in step (2) is replaced with “anhydrous ethanol”.

[0029] In Comparative Example 3, after the removal of the fluorine-containing substances, zinc oxide, the decomposition product of zinc lactate, cannot form a raised structure on the surface of the glass cover. In addition, zinc oxide itself is a hydrophilic material, and water or oil will spread on the surface of the glass cover of Comparative Example 3, making it easier to adhere to dust in the air. The self-cleaning effect of zinc oxide will quickly become ineffective, and its surface performance is not as good as that of ordinary untreated glass. Comparative Example 4 This comparative example proposes a glass cover plate, the preparation method of which is the same as that of Example 1, except that in step (4), "after the surface is completely dry, anneal at 200°C for 30 min" is replaced with "after the surface is completely dry, anneal at 400°C for 30 min".

[0030] In Comparative Example 4, although heat treatment at 400℃ is beneficial for improving the crystallinity of zinc oxide and increasing its photocatalytic ability, the fluorinated silane coupling agent, being an organic compound, will carbonize and decompose at 400℃, completely losing its hydrophobic and oleophobic effects, resulting in performance similar to Comparative Example 3. In addition, excessive sintering and particle coarsening of zinc oxide can lead to severe light scattering, and carbonization of fluorinated substances can cause the coating to yellow and blacken, further reducing the light transmittance of the glass cover. Such a glass cover cannot be used in the display screen field. The glass covers prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to performance tests. The specific test items are as follows, and the test results are shown in Table 1. Transmittance test: The transmittance of the glass covers prepared in Examples 1-4 and Comparative Examples 1-4 was measured using a spectrophotometer; Contact angle test: The water contact angle and oil static contact angle of the glass covers made in Examples 1-4 and Comparative Examples 1-4 were tested using a JC2000D1 contact angle measuring instrument. Self-cleaning test: Oleic acid was used as a representative of organic pollutants. Oleic acid was evenly applied to the glass cover surfaces of Examples 1-4 and Comparative Examples 1-4. After irradiation with visible light for 12 hours, the static contact angle of water was tested again, and the static contact angle recovery rate of water was calculated.

[0031] Table 1 Performance data of glass cover

[0032] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a self-cleaning superhydrophobic and oleophobic glass cover, characterized in that, Includes the following steps: S1. Prepare solution I containing zinc lactate; S2. Prepare solution II containing fluorosilane coupling agent; S3. Mix solution I, solution II and lactic acid solution thoroughly and allow to age to obtain coating solution; S4. The coating liquid is placed on the glass surface and heat-treated to obtain a self-cleaning superhydrophobic and oleophobic glass cover.

2. The method for preparing the self-cleaning superhydrophobic and oleophobic glass cover plate according to claim 1, characterized in that, In step S1, the concentration of the zinc lactate solution is 3-5 wt%.

3. The method for preparing the self-cleaning superhydrophobic and oleophobic glass cover plate according to claim 1 or 2, characterized in that, In step S2, the concentration of the fluorinated silane coupling agent is 0.5-3 wt%.

4. The method for preparing the self-cleaning superhydrophobic and oleophobic glass cover plate according to any one of claims 1-3, characterized in that, In step S3, the volume ratio of solution I to solution II is 1:5-20.

5. The method for preparing the self-cleaning superhydrophobic and oleophobic glass cover plate according to any one of claims 1-4, characterized in that, In step S3, the aging temperature is 30-40℃ and the aging time is 1-2 hours.

6. The method for preparing the self-cleaning superhydrophobic and oleophobic glass cover plate according to any one of claims 1-5, characterized in that, In step S4, the heat treatment includes drying and annealing.

7. The method for preparing the self-cleaning superhydrophobic and oleophobic glass cover plate according to claim 6, characterized in that, In step S4, the drying temperature is 50-90℃ and the drying time is 10-20 min.

8. The method for preparing the self-cleaning superhydrophobic and oleophobic glass cover plate according to claim 6 or 7, characterized in that, In step S4, the annealing temperature is 180-220℃ and the annealing time is 30-100min.

9. A self-cleaning superhydrophobic and oleophobic glass cover, characterized in that, It is prepared by the method described in any one of claims 1-8.

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