CN104449357B - A kind of transparent hydrophobic coating material and the method preparing transparent hydrophobic coating thereof - Google Patents

Abstract

The invention discloses a transparent super-hydrophobic coating material, the raw material of which comprises gas-phase silicon dioxide nano-particle dispersion liquid composed of gas-phase silicon dioxide nano-particles and a solvent and a hydrophobic treatment agent. The invention also discloses a preparation method of the transparent super-hydrophobic coating. The coating with the micro-nano structure is prepared by wiping the substrate with the gas-phase silica nano particle dispersion, and then the surface is hydrophobized by a hydrophobic treatment agent. The superhydrophobic coating material provided by the present invention can flexibly change the hydrophobic treatment method according to the different application substrates. The method for preparing the superhydrophobic coating requires less equipment, and the cost of use is extremely low. The method is simple, convenient to apply, and can be applied on a large area Preparation of efficient and multifunctional superhydrophobic coatings; the prepared superhydrophobic coatings have excellent superhydrophobicity, high transparency, droplet impact resistance, temperature and pH stability, durability, and can be wiped repeatedly. Applies to almost all currently known solid surfaces.

Description

A kind of transparent superhydrophobic coating material and the method for preparing transparent superhydrophobic coating thereof

technical field

The present invention relates to the technical field of hydrophobic coating materials, in particular to a hydrophobic coating material that has both optical transparency, durability, droplet impact resistance, temperature and pH stability, renewability, and can be applied to the surface of various materials. Transparent superhydrophobic materials and coatings prepared therefrom.

Background technique

Many biological surfaces in nature have special surface wetting behavior. The researchers found that the contact angles greater than 150° could be obtained by putting water droplets on the upper surface of lotus leaves, rice leaves, and water strider feet. Such surfaces exhibiting super-wetting resistance to water droplets are called superhydrophobic surfaces. After further scientific research, it was found that these biological surfaces all have rough structures on a microscopic scale. These microstructures prevent water droplets from completely infiltrating the surface when they come into contact with the surface, and air is retained inside the microstructure to form air pockets. Due to the existence of air pockets, Water droplets can easily slide off the surface. Due to its special surface anti-wetting behavior, the superhydrophobic surface has the characteristics of waterproof and self-cleaning. Inspired by this, the research and preparation of superhydrophobic surfaces has attracted extensive attention and attention. At the same time, the superhydrophobic coating with transparency has great potential application value in the application fields with high optical requirements, such as automobile windshield, building window glass, swimming goggle eyepiece and other fields.

According to the existing theory, the preparation of superhydrophobic surfaces generally needs to meet two key factors: one is that the surface has a microscopic structure, which is the biggest difference between superhydrophobic surfaces and general hydrophobic surfaces; the other is that the material itself has low surface energy. Or a layer of low surface energy substance attached to the surface. The preparation of superhydrophobic surfaces is generally carried out by various techniques and methods such as template method, photolithography method, plasma etching method, layer-by-layer assembly method, etc. These methods are only suitable for laboratory research or small-area superhydrophobic surface preparation due to the high demand for equipment.

The superhydrophobic coating developed based on mature coating technology can reduce the demand for equipment, simplify the construction steps, and bring the possibility of rapid and effective preparation of superhydrophobic surfaces in large areas.

Chinese patent application CN104046152A discloses a method for preparing a superhydrophobic coating, including step 1: taking 50 to 80 parts of a hydrophobic nanoparticle dispersion with a mass fraction of 2% to 15%, 20 to 50 Parts of polystyrene nanoparticle dispersion with a mass fraction of 1% to 10%, mixed with 0 to 30 parts of solvent, and ultrasonically dispersed to obtain a mixed solution; step 2: forming the mixed solution on a substrate surface and the substrate In the internal microstructure; Step 3: Dry the substrate in Step 2, then heat up to 160-230°C and bake to melt the polystyrene nanoparticles, take it out and dry it naturally, this method is too complicated to construct.

Chinese patent application CN103469184A discloses a method for preparing a superhydrophobic bismuth coating. Through electroless coating technology, a layer of metal bismuth is plated on the zinc sheet. The metal bismuth layer has a feather-like micro-nano composite structure, which exhibits superhydrophobicity after hydrophobic modification with long-chain fatty alcohols. However, this method is only suitable for metal surfaces, and the electroplating method pollutes a lot, and it is necessary to design corresponding size container equipment for surfaces of different sizes.

Chinese patent application CN103964701A discloses a preparation method of SiO ₂ /polytetrafluoroethylene hybrid superhydrophobic coating, which is hydrolyzed by silane coupling agent in alcohol-water mixed solvent under appropriate temperature and pH value conditions and combined with silica sol reaction to graft organic groups on the surface of silica particles; add a certain volume of PTFE emulsion and additives to the modified silica sol to make a uniform mixing system and age for a certain period of time to wait for coating treatment; prepare the coating, both It can effectively improve the adhesion between PTFE and the substrate, increase the hardness and wear resistance, and can also structure the roughness of the coating surface, thereby increasing the contact angle of the surface.

Chinese patent application CN103788802A discloses a method for preparing a superhydrophobic coating, comprising the following steps: preparing fluorine-modified polyacrylate; preparing silane coupling agent-modified nano-silica; dissolving the fluorine-modified polyacrylate forming a mixed liquid in an organic solvent, adding the silane coupling agent-modified nano silicon dioxide to the mixed liquid, and mixing uniformly to obtain a composite sol; coating the composite sol on a substrate, curing and drying. The prepared superhydrophobic coating has good hydrophobic properties and mechanical properties after curing, and also has good heat resistance properties.

Chinese patent application CN103753908A discloses a super-hydrophobic coating. The super-hydrophobic coating is composed of inorganic layers and organic layers alternately coated on the substrate. A permanent polyurethane layer, and both the bottommost and topmost layers are organic layers.

US patent application US2014/0106127A1 discloses a transparent and superhydrophobic polymer surface and a preparation method thereof. This patent partially embeds hydrophobic nanoparticles into the surface of a patterned sheet transparent polymer surface. After molding, the polymer surface not only retains its own transparency, but also possesses superhydrophobicity. This technology can be applied to prepare superhydrophobic surfaces in large areas, but it is more suitable for regular and flat surfaces because special equipment is required.

Chinese patent CN 102051120 A discloses a method for preparing a superhydrophobic coating with high mechanical strength, good durability and simple preparation. By spraying technology, the mixed dispersion of composite inorganic nanoparticles, polysiloxane compound, water and emulsifier or organic solvent is sprayed on the surface of the substrate, and the superhydrophobic surface is prepared by high temperature heat treatment. But the method still requires specific equipment - a spray gun to use and the coating is opaque.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the inability of existing superhydrophobic coating preparation methods to simultaneously obtain transparency, durability, erasability and recoatability, temperature and pH stability, droplet impact resistance, and versatility. etc., providing a transparent super-hydrophobic coating material and a preparation method of a transparent super-hydrophobic coating that can be produced in a factory assembly line or operated on different surfaces in daily life.

The raw materials of the transparent super-hydrophobic coating material of the present invention include: gas-phase silicon dioxide nano particle dispersion liquid and hydrophobic treatment agent.

The gas-phase silicon dioxide nano particle dispersion liquid is composed of gas-phase silicon dioxide nano-particles and a solvent, wherein the weight percentage of the gas-phase silicon dioxide nano-particles is 0.01%-50%.

Described solvent is water, alcohols, aliphatic hydrocarbons, aromatic hydrocarbons. The alcohol solvent is one or more of the following: ethanol, methanol, isopropanol, glycerol, etc.; the aliphatic hydrocarbon solvent is one or more of the following: n-hexane, cyclohexane; Described aromatic hydrocarbon solvent is toluene, xylene. In consideration of human health, non-toxic or low-toxic environment-friendly solvents are generally selected.

The specific surface area of the fumed silica nanoparticles is preferably from 10 m ² /g to 1000 m ² /g, preferably greater than 250 m ² /g. The weight percentage of the gas-phase silica nanoparticles is 0.01%-50%, preferably 0.1%-30%.

The hydrophobic treatment agent refers to a hydrophobic material with low surface energy, which can endow the coating with low surface energy, reduce or eliminate the polar bonds on the surface of the microstructure, form a protective layer on the surface of the microstructure, and simultaneously fix the The porous microstructure formed by silica nanoparticles provides the bonding force between the coating and the substrate. The hydrophobic material with low surface energy can be selected and controlled according to the application area and the service time of the coating.

The hydrophobic material with low surface energy generally includes one or more of the following: alkyl silane coupling agent, fluorine-containing alkyl silane coupling agent, fluorine-containing methacrylate polymer, fluorine-containing acrylate Polymers, organosilicon compounds, fluorine-containing organosilicon compounds, etc. details as follows:

(1) The alkylsilane coupling agent is selected from one or more of the following: formula I(a), formula I(b), formula I(c).

Among them, W represents a hydrolyzable group, which can be methoxy (-OCH ₃ ), ethoxy (-OC ₂ H ₅ ) or chlorine (-Cl), etc., considering factors such as reactivity, methoxy is preferred (-OCH ₃ ) or ethoxy group (-OC ₂ H ₅ ); R ₁ , R ₂ , and R ₃ independently represent straight-chain or branched-chain alkyl groups with 1 to 30 carbon atoms, considering the cost and difficulty of synthesis, etc. Factors, preferably a straight-chain or branched-chain alkyl group having 1 to 18 carbon atoms.

(2) The fluorine-containing alkylsilane coupling agent is selected from one or more of the following: formula II(a), formula II(b) and formula II(c).

Among them, W represents a hydrolyzable group, which can be methoxy (-OCH ₃ ), ethoxy (-OC ₂ H ₅ ) or chlorine (-Cl), etc. Considering factors such as reactivity, methoxy is preferred (-OCH ₃ ) or ethoxy group (-OC ₂ H ₅ ); Rf ₁ , Rf ₂ , and Rf ₃ independently represent a fluorine-containing straight-chain or branched chain alkyl group with 1 to 20 carbon atoms. Correspondingly, the alkyl group Part or all of the hydrogen atoms above are replaced by fluorine atoms, corresponding to 1 to 40 fluorine atoms. Considering factors such as cost and synthesis difficulty, a fluorine-containing straight-chain or straight-chain alkyl group with 1 to 12 carbon atoms is preferred, corresponding to The number of fluorine atoms is 1 to 36.

(3) The following fluorine-containing methacrylate monomers must be included in the fluorine-containing methacrylate polymer:

Among them, Yf is a fluorine-containing linear or branched alkyl group with a carbon number of 1 to 20. Correspondingly, some or all of the hydrogen atoms on the alkyl group are replaced by fluorine atoms, and the corresponding number of fluorine atoms is 1 to 40. Considering Due to factors such as cost and difficulty of synthesis, Yf preferably chooses a fluorine-containing straight-chain or branched chain alkyl group with 1 to 12 carbon atoms, corresponding to 1 to 36 fluorine atoms.

The fluorine-containing methacrylate polymer is a homopolymer or copolymer of monomers represented by formula III (a), and other methacrylate monomers and formula III (a) in different proportions can be added. The monomers are copolymerized. Among the present invention, the general formula of other methacrylate monomers is:

Wherein, Y is a straight-chain or branched-chain alkyl group with 1 to 20 carbon atoms, a straight-chain or branched-chain unsaturated hydrocarbon group containing a double bond, an unsaturated hydrocarbon group containing a benzene ring, and the like. Y is preferably a straight chain or branched chain alkyl group with 1 to 8 carbon atoms; a straight chain or branched chain unsaturated hydrocarbon group with a double bond with 1 to 8 carbon atoms; a benzene-containing group with 1 to 8 carbon atoms Ring unsaturated hydrocarbon group.

(4) The fluorine-containing acrylate polymer must contain the following fluorine-containing acrylate monomers:

Wherein, Xf is a fluorine-containing linear or branched alkyl group with a carbon number of 1 to 20. Correspondingly, some or all of the hydrogen atoms on the alkyl group are replaced by fluorine atoms, and the corresponding number of fluorine atoms is 1 to 40. Considering Factors such as cost and synthesis difficulty, Xf is preferably a fluorine-containing linear or branched chain alkyl group with 1 to 12 carbon atoms, corresponding to 1 to 36 fluorine atoms.

The fluorine-containing methacrylate polymer is a homopolymer or copolymer of the monomer shown in formula IV (a), considering factors such as cost and dispersibility in solvents, different proportions of other methyl acrylates can be added The acrylate monomer and the monomer represented by formula IV(a) are copolymerized. Among the present invention, the general formula of other methacrylate monomers is:

Wherein, X is a straight-chain or branched-chain alkyl group with 1 to 20 carbon atoms, a straight-chain or branched-chain unsaturated hydrocarbon group containing a double bond, an unsaturated hydrocarbon group containing a benzene ring, and the like. X is preferably a straight chain or branched chain alkyl group with 1 to 8 carbon atoms; a straight chain or branched chain unsaturated hydrocarbon group containing double bonds with 1 to 8 carbon atoms; a benzene ring with 1 to 8 carbon atoms unsaturated hydrocarbon groups.

(5) The general formula of the organosilicon compound and the fluorine-containing organosilicon compound is as follows:

Among them, R ₅₁ to R ₆₂ are independently a hydrocarbon group with 1 to 20 carbon atoms, a fluorine-containing hydrocarbon group with 1 to 20 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, etc., preferably carbon atoms A hydrocarbon group with 1 to 10 carbon atoms and a fluorine-containing hydrocarbon group with 1 to 10 carbon atoms. If R ₅₁ to R ₆₂ are all non-fluorine-containing groups, the compound represented by formula V is an organosilicon compound; if there is one or more fluorine-containing groups in R ₅₁ to R ₆₂ , the compound represented by formula V is a fluorine-containing organic compound. Silicon compounds. R ₅₁ to R ₆₂ are not hydroxyl at the same time, R ₅₃ , R ₅₄ , R ₅₅ , R ₅₈ , R ₅₉ , and R ₆₀ are not hydroxyl at the same time, R ₅₁ , R ₅₂ , and R ₅₇ are not hydroxyl at the same time, R ₅₆ , R ₆₀ , R ₆₁ are not hydroxyl groups at the same time; n, m, p are independently integers from 0 to 1000, and cannot be 0 at the same time; the compound shown in formula V contains at least two hydroxyl groups or alkoxy groups or the total number of hydroxyl groups and alkoxy groups is not less than 2. The aforementioned hydrocarbon group is preferably an alkyl group.

The present invention also provides a transparent super-hydrophobic coating prepared from the above-mentioned transparent super-hydrophobic coating material.

The present invention also provides a preparation method for a transparent superhydrophobic coating, comprising:

(1) obtaining a stable dispersion of gas-phase silica nanoparticles by dispersing and preparing gas-phase silica nanoparticles in a solvent;

(2) Add the fumed silica nanoparticle dispersion liquid dropwise to the cloth with lines (not flat), so that the cloth is wetted by the fumed silica nanoparticle dispersion liquid;

(3) Wipe the wet cloth on the surface of the substrate;

(4) After the solvent is completely volatilized, the coating is subjected to hydrophobic treatment with a hydrophobic treatment agent.

The cloth in step (2) is a woven or non-woven cloth with a certain surface pattern or surface hole structure, and the cloth can be quickly and completely wetted by the solvent.

The substrate described in step (3) includes glass, metal, plastic, rubber, concrete, paper and the like.

The hydrophobization treatment described in step (4) can be divided into the following categories according to the difference of its treatment method:

(1) Chemical vapor deposition (chemical vapor deposition, CVD), the alkyl silane coupling agent or fluorine-containing alkyl silane coupling agent in the hydrophobic treatment agent and the surface obtained by wiping are placed in a closed container, After the coupling agent is vaporized, it reacts and settles to the surface of the microstructure obtained by wiping, so as to perform hydrophobic treatment on the surface of the microstructure. More preferably, vacuumize or heat the container in a closed container to increase the vapor density of the coupling agent and enhance the effect of hydrophobic treatment.

(2) Spraying, dissolving or stably dispersing the hydrophobic treatment agent in the solvent, and then spraying it on the surface of the coating obtained by wiping by spraying equipment for hydrophobic treatment. In the present invention, the employed alkylsilane coupling agent and fluorine-containing alkylsilane coupling agent can be dissolved in solvents such as ethanol, isopropanol, toluene; organosilicon compound, fluorine-containing organosilicon compound can be dissolved in ethanol, Solvents such as isopropanol and toluene or dispersed in water. Fluorine-containing methacrylates and fluorine-containing acrylates can be dissolved (less fluorine-containing monomer content) or dispersed (more fluorine-containing monomer content) in solvents according to the content of fluorine-containing monomers. Generally, toluene, xylene, etc. have better solubility for fluorine-containing methacrylates and fluorine-containing acrylates. The concentration of the solution of the hydrophobic treatment agent used for spraying is preferably 0.01%-30%, more preferably 0.05%-20%. The percentages are mass percentages.

Technical effect of the present invention is:

1. The preparation method of the superhydrophobic coating material and coating of the present invention is very simple and convenient. The dispersion liquid of gas phase silica nanoparticles can be obtained by magnetic stirring or ultrasonic dispersion, and the gas phase two Silicon oxide nanoparticles are coated on the surface of the substrate, and the solvent quickly evaporates to obtain a porous microstructure without extreme conditions such as high temperature and high pressure. It is not only easy to promote in industry, but also has application prospects in daily life. When the superhydrophobic function is not needed or the coating is damaged by accidental factors, it can be quickly erased by scrubbing without damaging the surface properties of the original substrate. When the super-hydrophobic function is required, it can be quickly wiped and renewable.

2. The superhydrophobic coating of the present invention has excellent transparency, and even a superhydrophobic coating with a certain anti-reflection effect can be prepared through control.

3. The superhydrophobic coating of the present invention can be used in the temperature range of -30°C to 400°C.

4. The superhydrophobic coating of the present invention exhibits stable superhydrophobicity to aqueous solutions with a pH in the range of 1 to 14, and exhibits stable anti-wetting properties for complex water dispersion systems such as coffee and milk, and at the same time It also has a certain degree of superoleophobicity, and exhibits stable superhydrophobicity for droplets of different volumes.

5. The superhydrophobic coating of the present invention has a self-cleaning function, and can perfectly imitate the self-cleaning ability of lotus leaves.

6. The superhydrophobic coating of the present invention has strong droplet impact resistance, and can be immersed in water for a long time to maintain superhydrophobicity.

7. The superhydrophobic coating of the present invention is suitable for almost all known solid surfaces.

Description of drawings

Fig. 1 is the particle structure schematic diagram of the silica nanoparticle that the present invention adopts;

Fig. 2 is the scanning electron microscope picture of the superhydrophobic coating that the embodiment of the present invention 1 makes;

Fig. 3 is the contact angle test figure of superhydrophobic coating and water droplet that the embodiment of the present invention 1 makes;

Fig. 4 is the photograph that the superhydrophobic coating that the embodiment of the present invention 1 makes is placed on the paper and drips the water drop that is dyed by blue ink on the coating surface;

Fig. 5 is the demonstration diagram of self-cleaning function of superhydrophobic coating that the embodiment of the present invention 1 makes;

Fig. 6 is the contact angle data measured after the superhydrophobic coating that the embodiment of the present invention 1 makes is immersed in water for different times;

Figure 7 is the contact angle data measured after the superhydrophobic coating made in Example 1 of the present invention is subjected to the impact of water droplets of different masses;

Fig. 8 is the contact angle and rolling angle data of the superhydrophobic coating that the embodiment 1 of the present invention makes to the droplet of different pH values;

Fig. 9 is the contact angle data of repeated coating-cleaning of the same piece of glass by the superhydrophobic coating preparation method described in Example 1 of the present invention.

detailed description

Unless otherwise specified, various raw materials in the present invention are commercially available products; or can be obtained according to general preparation methods in the art. Unless otherwise specified or explained, the technical terms used herein are the same as the conventional terms in this field.

Example 1

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 300m ² /g) and 20g of absolute ethanol respectively, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to obtain uniform and stable Dispersions.

2. Cut out a textile cloth of a certain size, and soak the textile cloth with the dispersion liquid in step 1. Wipe the glass surface with the woven cloth.

3. After the ethanol is completely volatilized, put the wiped glass and 200 μL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane into a closed desiccator and heat it. Incubate at 180°C for 3h. The glass is then taken out of the desiccator to obtain a superhydrophobic coating.

Observation by SEM reveals that the coating has a porous microstructure (Figure 2). The contact angle of the superhydrophobic coating to the droplet was measured by a contact angle tester as 165.7° (Fig. 3), and the rolling angle was 1°. Figure 4 shows that the superhydrophobic coating has excellent transparency. Figure 5 shows that the superhydrophobic coating has self-cleaning ability.

Example 2

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 100m ² /g) and 20g of water respectively, and disperse the fumed silica nanoparticles in water by magnetic stirring and ultrasonic disperser to prepare a uniform and stable dispersion .

2. Cut out a non-woven fabric of a certain size, soak the non-woven fabric with the dispersion in step 1, and then wipe it on the glass surface.

3. After the water is completely evaporated, put the coated glass and 200 μL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane into a closed desiccator and heat it. Incubate at 100°C for 3h. The glass is then removed from the desiccator to produce a superhydrophobic coating.

The superhydrophobic coating has a contact angle of 162.1° and a rolling angle of 2°. Other properties such as transparency, self-cleaning ability, etc. are the same as in Example 1.

Example 3

1. Weigh 0.1g of fumed silica nanoparticles (with a specific surface area of 600m ² /g) and 50g of absolute ethanol, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to prepare uniform and stable of the dispersion.

2. Cut out a textile cloth of a certain size, soak the textile cloth with the dispersion in step 1, and then wipe the glass surface.

3. After the ethanol is completely volatilized, put the coated glass and 200 μL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane into a closed desiccator and heat it. Incubate at 160°C for 3h. The glass is then removed from the desiccator to produce a superhydrophobic coating.

The superhydrophobic coating has a contact angle of 168.5° and a rolling angle of 2°. Transparency is better than Example 1.

Example 4

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 300m ² /g) and 20g of absolute ethanol, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to prepare uniform and stable of the dispersion.

2. Cut out a textile cloth of a certain size, soak the textile cloth with the dispersion liquid in step 1, and wipe the glass surface.

3. After the ethanol is completely volatilized, put the coated glass together with 200 μL of methyltrimethoxysilane into a closed desiccator, heat it, and keep it warm at 60°C for 4 hours. The glass is then removed from the desiccator to produce a superhydrophobic coating.

The superhydrophobic coating has a contact angle of 164.2°, a rolling angle of 3°, and excellent transparency and self-cleaning ability.

Example 5

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 300m ² /g) and 10g of absolute ethanol respectively, and disperse the hydrophobic fumed silica nanoparticles in ethanol by magnetic stirring and an ultrasonic disperser to prepare uniform stable dispersion.

2. Cut out a woven cloth of a certain size (1cm×5cm), soak the woven cloth with the dispersion liquid in step 1, and then wipe the glass surface.

3. After the ethanol is completely volatilized, put the coated glass together with 200 μL of methyltrimethoxysilane into a closed desiccator, heat it, and keep it warm at 60°C for 4 hours. The glass is then removed from the desiccator to produce a superhydrophobic coating.

The contact angle of this superhydrophobic coating is 164.2 °, and the rolling angle is 3 °, and the transparency is slightly worse than that of Example 1.

Example 6

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 800m ² /g) and 20g of absolute ethanol, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to prepare uniform and stable of the dispersion.

2. Cut out a woven fabric of a certain size (1cm×5cm), and soak the woven fabric with the dispersion liquid in step 1. Then wipe the surface of the aluminum sheet.

3. After the ethanol is completely volatilized, put the coated aluminum sheet and 200 μL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane into a closed desiccator, and heat it , at 200°C for 4h. Then the aluminum sheet was taken out from the desiccator to obtain the superhydrophobic coating.

The superhydrophobic coating has a contact angle of 167.3° and a rolling angle of 1°.

Example 7

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 300m ² /g) and 20g of isopropanol, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to prepare uniform and stable of the dispersion.

2. Cut out a textile cloth of a certain size, and soak the textile cloth with the dispersion liquid in step 1. The surface of the polymethyl methacrylate molded disc was then wipe-coated.

3. After the isopropanol is completely volatilized, put the coated glass and 200 μL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane into a closed desiccator at 60°C Keep warm for 1h. The discs were then removed from the desiccator to obtain a superhydrophobic coating.

The superhydrophobic coating has a contact angle of 163.9° and a rolling angle of 1°, and still has high transparency, self-cleaning ability, etc.

Example 8

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 300m ² /g) and 20g of n-hexane, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to prepare uniform and stable Dispersions.

2. Cut out a textile cloth of a certain size, and soak the textile cloth with the dispersion liquid in step 1. Then wipe the surface of A4 paper.

3. After the n-hexane is completely volatilized, put the coated A4 paper and 200 μL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane into a closed desiccator, add Warm at 40°C for 3h. Then take it out from the desiccator to get the superhydrophobic coating.

The superhydrophobic coating has a contact angle of 162.5° and a rolling angle of 2°.

Example 9

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 300m ² /g) and 20g of absolute ethanol, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to prepare uniform and stable of the dispersion.

2. Cut out a textile cloth of a certain size, and soak the textile cloth with the dispersion liquid in step 1. Then wipe the glass surface.

3. After the ethanol is completely volatilized, spray the 5% fluorine-containing methacrylate resin dispersion onto the glass surface, and the superhydrophobic coating can be prepared after the solvent is volatilized.

The superhydrophobic coating has a contact angle of 159.8°, a rolling angle of 4°, and excellent transparency.

Example 10

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 400m ² /g) and 20g of absolute ethanol, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to prepare uniform and stable of the dispersion.

2. Cut out a textile cloth of a certain size, and soak the textile cloth with the dispersion liquid in step 1. Then wipe the glass surface.

3. After the ethanol is completely volatilized, spray 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane ethanol solution with a mass concentration of 1% on the coated glass, and let the glass stand for 30 minutes That is, a superhydrophobic coating is obtained.

The superhydrophobic coating has a contact angle of 161.3 ^o and a rolling angle of 3 ^o . Other properties such as transparency, self-cleaning ability etc. are similar to Example 1.

Example 11

1. Weigh 0.2g of fumed silica nanoparticles (with a specific surface area of 300m ² /g) and 20g of absolute ethanol, and disperse the fumed silica nanoparticles in ethanol by magnetic stirring and ultrasonic disperser to prepare uniform and stable of the dispersion.

2. Cut out a textile cloth of a certain size, soak the textile cloth with the dispersion in step 1, and then wipe the glass surface.

3. After the ethanol is completely volatilized, the ethanol solution of the organosilicon compound (concentration is 3%) is sprayed on the coated glass, and the super-hydrophobic coating is obtained by keeping the glass still.

The superhydrophobic coating has a contact angle of 158.9° and a rolling angle of 5°. Other properties such as transparency, self-cleaning ability, etc. are the same as in Example 1.

Performance Testing

1. Durability test

The superhydrophobic coating prepared in Example 1 was immersed in water, and the contact angle and rolling angle were measured after taking it out at regular intervals, as shown in FIG. 6 . It can be seen that within the test time range, the superhydrophobic coatings all exhibit stable contact angles and rolling angles, and the contact angles are all above 160°, and the rolling angles are all less than 2°.

After the superhydrophobic coating prepared in Example 1 was fixed, a certain quality of water was used to impact the surface of the superhydrophobic coating at regular intervals, and then the contact angle and rolling angle were measured, as shown in FIG. 7 . It can be seen that the superhydrophobic coating can still maintain stable superhydrophobicity under the continuous impact of 10kg of water, indicating that the superhydrophobic coating of the present invention has excellent water drop impact resistance.

2. Corrosion resistance liquid test

Drops with pH values from 1 to 14 were added onto the superhydrophobic coating in Example 1, and then the contact angle and rolling angle were measured, as shown in FIG. 8 . It can be seen that the superhydrophobic coating exhibits superhydrophobicity for droplets in the entire pH range. It shows that the superhydrophobic coating of the present invention possesses certain ability of resisting corrosive liquid.

3. Anti-wetting test of droplets in organic solvents and complex aqueous dispersions

Different droplets are added to the superhydrophobic coating in Example 1, then the contact angle and rolling angle are measured, as shown in Table 1. As can be seen from Table 1, this superhydrophobic coating has possessed certain superoleophobic properties, and It also has stable super anti-wetting properties for complex aqueous dispersion systems.

Table 1 Droplet surface tension and contact angle and rolling angle on superhydrophobic coating

4. Repeatability test

Prepare the superhydrophobic coating according to the method in Example 1, measure the contact angle and rolling angle, then clean the coated glass with a commercially available glass cleaning agent, measure the contact angle, repeat the above steps, and investigate the present invention The repeatability of the method used is shown in Figure 9. Visible, the method of the present invention is a kind of gentle method, can not cause damage to substrate, can adopt method of the present invention to carry out repeated coating to substrate surface, and can easily remove coating when unnecessary.

Claims (7)

1. A transparent super-hydrophobic coating, is characterized in that, adopts super-hydrophobic coating material to prepare, and the raw material of described transparent super-hydrophobic coating material comprises: fumed silica nano particle dispersion liquid and hydrophobic treatment agent; The fumed silica nanoparticle dispersion liquid is composed of fumed silica nanoparticles and a solvent; The preparation method of described superhydrophobic coating comprises: (1) obtaining a stable dispersion of gas-phase silica nanoparticles by dispersing and preparing gas-phase silica nanoparticles in a solvent; (2) adding the fumed silica nanoparticle dispersion liquid dropwise to the cloth with lines, so that the cloth is wetted by the fumed silica nanoparticle dispersion liquid; (3) Wipe the wet cloth on the surface of the substrate; (4) After the solvent is completely volatilized, use a hydrophobic treatment agent to perform hydrophobic treatment on the surface of the coating. 2. transparent superhydrophobic coating as claimed in claim 1, is characterized in that, described solvent is water, alcohols, aliphatic hydrocarbons or aromatic hydrocarbons; Described alcoholic solvent is following one or more Species: ethanol, methanol, isopropanol, glycerol; the aliphatic hydrocarbon solvent is one or more of the following: n-hexane, cyclohexane; the aromatic hydrocarbon solvent is toluene or xylene. 3. The transparent superhydrophobic coating according to claim 1, wherein the hydrophobic treatment agent is an alkyl silane coupling agent, a fluorine-containing alkyl silane coupling agent, a fluorine-containing methacrylate polymer , fluorine-containing acrylate polymers, organosilicon compounds or fluorine-containing organosilicon compounds. 4. transparent superhydrophobic coating as claimed in claim 1, is characterized in that, the mass percent of fumed silica nanoparticles in the described fumed silica nanoparticle dispersion liquid of step (1) is 0.01%～50% . 5. transparent superhydrophobic coating as claimed in claim 3, is characterized in that, the hydrophobization treatment described in step (4) is a kind of in the following method: a) with alkylsilane coupling agent or fluorine-containing alkane The base silane coupling agent is used to hydrophobize the surface of the coating by chemical vapor deposition, the treatment temperature is 30-200 °C, and the treatment time is 0.5-10h; b) The alkyl silane coupling agent or fluorine-containing alkyl silane coupling The joint agent is dissolved or dispersed in a volatile solvent and sprayed on the surface of the coating for hydrophobic treatment; c) Dissolving or dispersing the fluorine-containing methacrylate polymer or fluorine-containing acrylate polymer in the solvent for spraying Hydrophobizing treatment is carried out on the surface of the coating; d) Spraying an organosilicon compound or a fluorine-containing organosilicon compound on the surface of the coating and curing for hydrophobizing treatment. 6. transparent superhydrophobic coating as claimed in claim 5, is characterized in that, in described hydrophobization treatment method b), the alkylsilane coupling agent or fluorine-containing alkylsilane coupling agent solution for spraying Or the concentration of the dispersion liquid is 0.01% to 30%. 7. The transparent superhydrophobic coating as claimed in claim 5, characterized in that, in the described hydrophobization treatment method c), the fluorine-containing methacrylate polymer and fluorine-containing acrylate polymer used for spraying The concentration of the dispersion liquid is 0.05% to 30%.