Modified gas-phase nano SiO2, composite emulsion, super-hydrophobic self-cleaning coating and preparation method of super-hydrophobic self-cleaning coating

Abstract

The invention provides modified gas-phase nano SiO2, a composite emulsion, a super-hydrophobic self-cleaning coating and a preparation method thereof, and belongs to the field of material protection. The surfaces of nano particles of the modified gas-phase nano SiO2 are provided with long-chain hydrocarbons and contain unsaturated double bonds; wherein the number of carbon atoms of the long chain hydrocarbon is 5-50. According to the invention, the hydrophilic gas-phase nano SiO2 is modified, so that the surface roughness is improved, and the wear resistance and corrosion resistance of the coating are improved.

Description

Technical Field

[0001] The invention belongs to the field of material protection, and in particular relates to a modified gas-phase nano-SiO2, a composite emulsion, a super-hydrophobic self-cleaning coating and a preparation method thereof. Background Art

[0002] As the global demand for clean energy continues to grow, solar energy has been widely used as a sustainable form of energy, and the number of photovoltaic panels has increased dramatically. However, photovoltaic panels face many problems in outdoor environments, among which dust, dirt, water stains and the adhesion of various pollutants are key factors affecting their performance.

[0003] Especially in the deserted area, dust particles in the air will gradually settle on the surface of the photovoltaic panels, forming a layer of covering, blocking the effective incidence of sunlight, reducing the light transmittance of the photovoltaic panels, and thus causing a significant decrease in the photoelectric conversion efficiency. In addition, water stains left after rain, oil pollution in the atmosphere, and pollutants such as microorganisms will further aggravate this problem. Traditional photovoltaic panel cleaning methods mainly include manual cleaning and mechanical cleaning. Manual cleaning is inefficient, labor-intensive and costly. At the same time, during the cleaning process, improper operation may cause scratches and other damage to the surface of the photovoltaic panels, affecting their service life. Although mechanical cleaning equipment has improved the cleaning efficiency to a certain extent, it also has problems such as large initial investment in equipment, high energy consumption, and the need for regular maintenance. In addition, frequent cleaning operations themselves will also cause certain wear and tear on the protective coating on the surface of the photovoltaic panels.

[0004] Therefore, a new superhydrophobic self-cleaning coating is needed. Summary of the invention

[0005] In order to solve the above problems, the present technology proposes a modified gas-phase nano-SiO2. The modified gas-phase nano-SiO2 can improve the surface roughness and enhance the wear resistance and corrosion resistance of the coating.

[0006] The present invention also provides a SiO2 / VTES / MMA composite emulsion comprising the modified gas-phase nano-SiO2. The composite emulsion preparation method uses water as a solvent, is more environmentally friendly, and is suitable for photovoltaic panels in desert environments, which is more practical.

[0007] Another object of the present invention is to provide a super hydrophobic self-cleaning coating.

[0008] The present invention also provides a preparation method of the modified gas-phase nano-SiO2, SiO2 / VTES / MMA composite emulsion and super-hydrophobic self-cleaning coating.

[0009] In order to achieve the above purpose, the following technical solutions are adopted:

[0010] A modified gas-phase nano-SiO2, wherein the surface of the nano-particles of the modified gas-phase nano-SiO2 carries long-chain hydrocarbons and contains unsaturated double bonds; wherein the number of carbon atoms of the long-chain hydrocarbons is 5 to 50, and the number of carbon atoms is preferably greater than 10. Grafting long-chain hydrocarbons with 5 to 50 carbon atoms on the surface of the nano-particles of the modified gas-phase nano-SiO2 is conducive to achieving a good hydrophobic effect; at the same time, the surface of the nano-particles of the modified gas-phase nano-SiO2 carries unsaturated double bonds (C=O and C=C), which can undergo grafting reaction with polymers. By modifying the hydrophilic gas-phase nano-SiO2, the surface roughness is improved, and the wear resistance and corrosion resistance of the coating are improved.

[0011] Preferably, the molecular structure of the modified gas-phase nano-SiO2 is as follows:

[0012] ;

[0013] Among them, n is 5~50.

[0014] More preferably, the molecular structure of the modified gas-phase nano-SiO2 is:

[0015] ;

[0016] or ;

[0017] or .

[0018] The above-mentioned method for preparing modified gas-phase nano-SiO2 comprises the following steps:

[0019] S11: heating and uniformly mixing ethanol, ammonia water and TEOS; wherein the volume ratio of ethanol, ammonia water and TEOS is 150-260:6-10:16-25;

[0020] S12: Add hydrophilic gas-phase nano-SiO2 to the mixture obtained in step S11, add the organosilicon compound and KH-570 after mixing, mix them evenly, and react for a certain time; wherein the ratio of the added hydrophilic gas-phase nano-SiO2 to TEOS is 0.1-0.2 g / ml; the mass ratio of the hydrophilic gas-phase nano-SiO2, the organosilicon compound and KH-570 is 1:1:1-2:1:1; the organosilicon compound in this embodiment is preferably polysiloxane, and more preferably, the organosilicon compound is a trimethoxysilane organosilicon compound;

[0021] S13: The solution obtained in step S12 is centrifuged, washed, dried and ground to obtain modified gas-phase nano-SiO2.

[0022] A method for preparing a SiO2 / VTES / MMA composite emulsion, which uses the modified gas-phase nano-SiO2, and the method for preparing the SiO2 / VTES / MMA composite emulsion comprises the following steps:

[0023] S21: dissolving the reaction monomers MMA and VTES, the crosslinking agent DEGDA, the emulsifier AEO-9 and AES in deionized water, and mixing them evenly to obtain a homogeneous emulsion;

[0024] S22: adding an initiator to the homogeneous emulsion obtained in step S1, heating and stirring; the initiator may be various commonly used initiators, such as peroxide initiators, azo initiators, dithioxanthone, etc.;

[0025] S23: Add modified gas-phase nano-SiO2 to the solution obtained in step S2, continue heating and stirring, and react for a certain period of time to obtain a SiO2 / VTES / MMA composite emulsion;

[0026] The mass ratio of MMA to VTES is 2-3; the mass ratio of MMA to DEGDA is 35-60; the mass ratio of MMA to AEO-9 is 120-200, the mass ratio of MMA to AES is 280-330, and the mass ratio of the added deionized water to MMA is 2-4;

[0027] Preferably, the mass ratio of MMA, VTES, DEGDA, AEO-9, AES and deionized water is 2600:1200:70:21:9:8000~2900:1000:50:15:9:6000;

[0028] The mass ratio of the MMA to the modified gas-phase nano-SiO2 is 7-16;

[0029] The mass ratio of the initiator to the modified gas-phase nano-SiO2 is 7-20.

[0030] A SiO2 / VTES / MMA composite emulsion is prepared by using the above-mentioned method for preparing the SiO2 / VTES / MMA composite emulsion.

[0031] A method for preparing a super hydrophobic self-cleaning coating, which uses the above-mentioned SiO2 / VTES / MMA composite emulsion, and the method for preparing the super hydrophobic self-cleaning coating comprises the following steps:

[0032] S31: coating the SiO2 / VTES / MMA composite emulsion onto a glass substrate; the thickness of the coating obtained after coating is 1-2 mm;

[0033] S32: The coated glass substrate is baked, and a super-hydrophobic self-cleaning coating is obtained after cooling.

[0034] Preferably, before coating, the glass substrate is cleaned; the cleaning process is to clean the glass substrate in acetone, ethanol and deionized water in sequence.

[0035] Preferably, after the cleaning process, the glass substrate is subjected to a secondary cleaning process; the secondary cleaning process is to immerse the cleaned glass substrate in a mixed solution of concentrated sulfuric acid and hydrogen peroxide;

[0036] The temperature of the mixed solution of concentrated sulfuric acid and hydrogen peroxide is 45-55°C.

[0037] And / or, the volume ratio of concentrated sulfuric acid to hydrogen peroxide in the mixed solution is 2:1 to 5:1.

[0038] Preferably, the coating process in step S31 is a multiple coating process.

[0039] More preferably, the coating treatment is carried out by spraying with a spray gun, the nozzle is about 15 cm to 20 cm away from the substrate, and the spraying time is 2 to 3 seconds.

[0040] Compared with the prior art, this technology has the following beneficial effects:

[0041] (1) The present invention improves the surface roughness and the wear resistance and corrosion resistance of the coating by modifying the hydrophilic gas-phase nano-SiO2.

[0042] (2) The SiO2 / VTES / MMA composite emulsion of the present invention uses water as solvent, is more environmentally friendly, and is suitable for photovoltaic panels in desert environments, which is more practical.

[0043] (3) The super-hydrophobic self-cleaning coating of the present invention is particularly suitable for photovoltaic panels that are exposed to dusty weather for a long time. While ensuring that the photovoltaic panels have a self-cleaning function, it can also ensure the high light transmittance and high durability of the coating.

[0044] (4) This technology uses a spray coating method to coat the photovoltaic panel glass substrate to construct a super-hydrophobic self-cleaning coating, thereby increasing the tightness and stability of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the modification process of the modified gas-phase nano-SiO2 of the present invention;

[0046] Figure 2 FIG. 1 is a diagram showing the preparation process of the SiO2 / VTES / MMA composite emulsion of the present invention;

[0047] Figure 3This is a water contact angle test diagram of Example 1 of the present invention;

[0048] Figure 4 A schematic diagram showing the change of WCA with the number of wear times in the mechanical durability test of the super hydrophobic self-cleaning coating prepared by the present invention;

[0049] Figure 5 TG curves of nano-SiO2, modified gas-phase nano-SiO2, VTES / MMA and SiO2 / VTES / MMA composite emulsions of the present invention;

[0050] Figure 6 This is a schematic diagram showing the effect of the modified gas-phase nano-SiO2 prepared by the present invention on the contact angle at different pH values;

[0051] Figure 7 VI curve and power generation curve of the photovoltaic panel coated with the super-hydrophobic self-cleaning coating of the present invention. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present technology in conjunction with the drawings in the embodiments of the present technology. Obviously, the described embodiments are only part of the embodiments of the present technology, not all of the embodiments. Based on the embodiments in the present technology, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present technology.

[0053] Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

[0054] Example 1

[0055] This example prepares modified gas-phase nano-SiO2.

[0056] The molecular structure of the modified gas-phase nano-SiO2 of this embodiment is:

[0057] .

[0058] The preparation method of gas-phase nano-SiO2 in this embodiment comprises the following specific steps:

[0059] (1) Add 200 mL of 90% ethanol solution, 8 mL of ammonia water, and 20 mL of TEOS (tetraethoxysilane) into a 500 mL three-necked flask and stir the mixture under a 40°C water bath for 4 h. After a period of reaction, TEOS hydrolyzes to generate SiO2 particles of about 250 nm.

[0060] (2) Add 3.0 g of hydrophilic gas-phase nano-SiO2 with a particle size of 7-30 nm, stir for 30 min, then add 2.5 g of HDTMS (hexadecyltrimethoxysilane) and 2.5 g of KH-570 (γ-methacryloxypropyltrimethoxysilane), continue heating and stirring for 6 h, and let stand at room temperature overnight;

[0061] (3) The solution was centrifuged at 5000 r / min for 6 min and washed with anhydrous ethanol three times. The separated sample was dried in an oven at 60 °C for 24 h and then ground with an agate mortar to obtain a sample powder.

[0062] The schematic diagram of the modification process is as follows: Figure 1 See Figure 1 The surface of the modified gas-phase nano-SiO2 obtained has long-chain hydrocarbons (in this embodiment, long-chain hydrocarbons with 15 carbon atoms), thereby achieving a good hydrophobic effect, and contains unsaturated double bonds (C=C), which can undergo grafting reaction with polymers. The reaction process is as follows:

[0063] .

[0064] Example 2

[0065] This example prepares modified gas-phase nano-SiO2.

[0066] A method for preparing gas-phase nano-SiO2 comprises the following specific steps:

[0067] (1) Add 190 mL of 90% ethanol solution, 6 mL of ammonia water, and 18 mL of TEOS to a 500 mL three-necked flask and stir magnetically in a 40°C water bath for 4 h.

[0068] (2) Add 2.5 g of hydrophilic gas-phase nano-SiO2 with a particle size of 7-30 nm, stir for 30 min, then add 2 g of HDTMS and 2 g of KH-570, continue heating and stirring for 6 h, and let stand at room temperature overnight;

[0069] (3) The solution was centrifuged at 5000 r / min for 6 min and washed with anhydrous ethanol three times. The separated sample was dried in an oven at 60 °C for 24 h and then ground with an agate mortar to obtain a sample powder.

[0070] The structural formula of the modified gas-phase nano-SiO2 obtained in Example 2 is the same as that in Example 1, and the surface of the modified gas-phase nano-SiO2 has a long-chain hydrocarbon of 15 carbon atoms.

[0071] Example 3

[0072] This example prepares modified gas-phase nano-SiO2.

[0073] A method for preparing gas-phase nano-SiO2 comprises the following specific steps:

[0074] (1) Add 150 mL of 90% ethanol solution, 10 mL of ammonia water, and 16 mL of TEOS to a 500 mL three-necked flask and stir magnetically in a 40°C water bath for 4 h.

[0075] (2) Add 3.2 g of hydrophilic gas-phase nano-SiO2 with a particle size of 7-30 nm, stir for 30 min, then add 3.2 g of hexaalkyltrimethoxysilane and 3.2 g of KH-570, continue heating and stirring for 6 h, and let stand at room temperature overnight;

[0076] (3) The solution was centrifuged at 5000 r / min for 6 min and washed with anhydrous ethanol three times. The separated sample was dried in an oven at 60 °C for 24 h and then ground with an agate mortar to obtain a sample powder.

[0077] The surface of the modified gas-phase nano-SiO2 obtained in Example 3 has a long-chain hydrocarbon with 5 carbon atoms. Its structural formula is as follows:

[0078] .

[0079] Example 4

[0080] This example prepares modified gas-phase nano-SiO2.

[0081] A method for preparing gas-phase nano-SiO2 comprises the following specific steps:

[0082] (1) Add 260 mL of 90% ethanol solution, 10 mL of ammonia water, and 25 mL of TEOS to a 500 mL three-necked flask and stir magnetically in a 40°C water bath for 4 h.

[0083] (2) Add 2.5 g of hydrophilic gas-phase nano-SiO2 with a particle size of 7-30 nm, stir for 30 min, then add 1.25 g of hexadecyltrimethoxysilane and 1.25 g of KH-570, continue heating and stirring for 6 h, and let stand at room temperature overnight;

[0084] (3) The solution was centrifuged at 5000 r / min for 6 min and washed with anhydrous ethanol three times. The separated sample was dried in an oven at 60 °C for 24 h and then ground with an agate mortar to obtain a sample powder.

[0085] The surface of the modified gas-phase nano-SiO2 obtained in Example 4 has a long-chain hydrocarbon of 50 carbon atoms. Its structural formula is as follows:

[0086] .

[0087] Example 5

[0088] This example prepares SiO2 / VTES / MMA composite emulsion using the modified gas-phase nano-SiO2 prepared in Example 1.

[0089] like Figure 2 As shown, a method for preparing a SiO2 / VTES / MMA composite emulsion specifically comprises the following steps:

[0090] (1) 14.0 g of reactive monomer MMA (methyl methacrylate) and 6.0 g of VTES (vinyl triethoxysilane), as well as 0.35 g of crosslinking agent DEGDA (diethylene glycol diacrylate), 0.105 g of emulsifier AEO-9 (fatty alcohol polyoxyethylene ether) and 0.045 g of AES (fatty alcohol polyoxyethylene ether sodium sulfate) were dissolved in 40.0 g of deionized water, and magnetically stirred at room temperature for a period of time until a homogeneous emulsion was obtained;

[0091] (2) The uniformly dispersed emulsion was added into a 250 mL three-necked flask equipped with a spherical reflux condenser, 80 mg of APS (ammonium persulfate) was added as an initiator, and mechanically stirred at 80 °C for 3 h;

[0092] (3) Add 1 g of the modified gas-phase nano-SiO2 prepared in Example 1, continue heating and stirring for 2 h, so that the double bonds on the surface of the nanoparticles react with the polymer, and finally obtain a SiO2 / VTES / MMA composite emulsion.

[0093] The modified gas-phase nano-SiO2 of this embodiment includes 250nm SiO2 (generated by hydrolysis of TEOS) and added 7~30nm hydrophilic gas-phase SiO2. Long-chain hydrocarbons and unsaturated bonds are grafted on the surfaces of these two modified gas-phase nano-SiO2. Modified gas-phase nano-SiO2 with different particle sizes can form an emulsion with higher aggregation, thereby improving the adhesion of the emulsion, making the super-hydrophobic self-cleaning coating have high durability.

[0094] Example 6

[0095] In this example, SiO2 / VTES / MMA composite emulsion was prepared.

[0096] A method for preparing a SiO2 / VTES / MMA composite emulsion comprises the following steps:

[0097] (1) 15.2 g of the reaction monomer MMA and 7 g of VTES, as well as 0.4 g of the crosslinker DEGDA, 0.13 g of the emulsifier AEO-9 and 0.052 g of AES were dissolved in 50 g of deionized water and magnetically stirred at room temperature for a period of time until a homogeneous emulsion was obtained;

[0098] (2) The uniformly dispersed emulsion was added into a 250 mL three-necked flask equipped with a spherical reflux condenser, 90 mg APS was added as an initiator, and mechanically stirred at 80 °C for 3 h;

[0099] (3) Add 1.1 g of the prepared modified nano-SiO2, continue heating and stirring for 2 h, so that the double bonds on the surface of the nanoparticles react with the polymer, and finally obtain SiO2 / VTES / MMA composite emulsion.

[0100] Example 7

[0101] In this example, SiO2 / VTES / MMA composite emulsion was prepared.

[0102] A method for preparing a SiO2 / VTES / MMA composite emulsion comprises the following steps:

[0103] (1) 14 g of reactive monomer MMA and 7 g of VTES, as well as 0.24 g of crosslinking agent DEGDA, 0.11 g of emulsifier AEO-9 and 0.043 g of AES were dissolved in 28 g of deionized water and magnetically stirred at room temperature for a period of time until a homogeneous emulsion was obtained;

[0104] (2) The uniformly dispersed emulsion was added into a 250 mL three-necked flask equipped with a spherical reflux condenser, 100 mg of APS was added as an initiator, and mechanically stirred at 80 °C for 3 h;

[0105] (3) Add 2 g of the prepared modified nano-SiO2, continue heating and stirring for 2 h, so that the double bonds on the surface of the nanoparticles react with the polymer, and finally obtain SiO2 / VTES / MMA composite emulsion.

[0106] Example 8

[0107] In this example, SiO2 / VTES / MMA composite emulsion was prepared.

[0108] A method for preparing a SiO2 / VTES / MMA composite emulsion comprises the following steps:

[0109] (1) 15 g of reactive monomer MMA and 5 g of VTES, as well as 0.42 g of crosslinking agent DEGDA, 0.075 g of emulsifier AEO-9 and 0.053 g of AES were dissolved in 60 g of deionized water and magnetically stirred at room temperature for a period of time until a homogeneous emulsion was obtained;

[0110] (2) The uniformly dispersed emulsion was added into a 250 mL three-necked flask equipped with a spherical reflux condenser, 130 mg of APS was added as an initiator, and mechanically stirred at 80 °C for 3 h;

[0111] (3) Add 0.94 g of the prepared modified nano-SiO2, continue heating and stirring for 2 h, so that the double bonds on the surface of the nanoparticles react with the polymer, and finally obtain SiO2 / VTES / MMA composite emulsion.

[0112] Example 9

[0113] This example prepares a super-hydrophobic self-cleaning coating.

[0114] The SiO2 / VTES / MMA composite emulsion prepared in Example 5 is used to obtain the super hydrophobic self-cleaning coating of the present technology by the following coating method, which specifically includes the following steps:

[0115] (1) The photovoltaic panel glass substrate was cleaned in acetone, ethanol and deionized water respectively, and then heated in a mixed solution of concentrated sulfuric acid (98%) and hydrogen peroxide (30%) in a volume ratio of 3:1 for 2 h at a temperature of 50°C.

[0116] (2) The prepared composite emulsion was sprayed onto a treated and clean glass substrate using a spray gun, with the nozzle about 15 cm to 20 cm away from the substrate. The spraying time was 2 s, and the spraying was performed three times with a time interval of 10 min each time.

[0117] (3) After spraying, the glass substrate is placed in an oven at 120°C for 1 hour and then cooled to room temperature to obtain a super-hydrophobic self-cleaning coating on the surface of the photovoltaic panel glass substrate.

[0118] The performance characterization test of each of the above embodiments specifically includes the following steps:

[0119] (1) Contact angle measurement: Use a WCA tester to measure the contact angle of a water droplet on the coating surface. Generally speaking, materials with a contact angle greater than 150° are considered super-hydrophobic materials. Figure 3 As shown, the left and right contact angles of the water droplet on the coating surface are both greater than 150°, indicating that the SiO2 / VTES / MMA composite emulsion prepared in Experimental Example 1 has good hydrophobic properties.

[0120] (2) Mechanical durability test: Take a piece of 1000-grit sandpaper, make the super-hydrophobic coating prepared in Example 9 face the rough surface of the sandpaper, place a 100 g weight on the sample to increase the friction between the substrate and the sandpaper, and move the sample back and forth along the ruler for 10 cm. These two movement processes are defined as one friction test cycle. After each friction test, the contact angle of the sample is tested. Figure 4 As shown in the figure, after dozens of load-bearing friction cycles, the contact angle of the coating surface fluctuates only within a small range, and after 60 cycles, the contact angle is still above 150°, indicating that the coating has very excellent mechanical durability. The cross-linked structure significantly enhances the intermolecular interaction force, forming a stable three-dimensional network structure, which can better resist deformation and damage when subjected to external forces, and improves the fatigue resistance and wear resistance of the coating. In addition, the nano-SiO2 particles are connected to the polymer through covalent bonds, which can significantly improve the wear resistance of the coating, thereby extending the service life of the coating.

[0121] (3) Thermal stability test: The nano-SiO2 particles before modification, the modified gas-phase nano-SiO2 particles prepared in Example 1, and the SiO2 / VTES / MMA composite emulsion were characterized using a TG analyzer. The samples were heated from 30°C to 700°C at a heating rate of 10°C / min in a nitrogen environment. Figure 5 As shown in the figure, nano-SiO2 has excellent thermal stability and can still exist at 700 ℃. The thermal stability of nano-SiO2 modified by silane coupling agent is reduced because the coupling agent does not have excellent thermal stability. On the one hand, the cross-linked network delays the thermal decomposition process of the polymer and improves the thermal stability of the composite material; on the other hand, the presence of nano-SiO2 can form a thermal barrier layer to reduce the transfer of heat to the inside of the polymer and further improve the thermal stability of the composite material.

[0122] (4) Chemical resistance test: The coated samples are immersed in solutions with different pH values, such as hydrochloric acid solution with pH = 1, distilled water with pH = 7, sodium hydroxide solution with pH = 13, etc. The immersion time can be set to 24-48 hours. After the immersion, take out the sample, rinse it with distilled water, and measure the contact angle after drying. The treatment results are as follows: Figure 6 As shown in Figure 2, the contact angle remains at 160° with the change of pH value, indicating that the SiO2 / VTES / MMA composite emulsion prepared in the experiment has good chemical resistance.

[0123] (5) Transmittance test: The power generation efficiency of photovoltaic panels without and with the super-hydrophobic self-cleaning coating of the present invention was tested by using a capacitor charge-discharge method. Figure 7As shown. At the beginning of the experiment, the power generation of the two photovoltaic panels was not much different. As the experiment progressed, the power generation of the photovoltaic panel coated with the superhydrophobic self-cleaning coating changed little compared with the beginning of the experiment; the power generation of the photovoltaic panel without treatment decreased significantly. The temperature-current characteristic method is used to calculate the current in each time interval. Using the temperature-current characteristic curve and experimental data, the current in each time interval is accumulated to measure the power generation.

[0124] The above two tests of power generation and power generation show that the super-hydrophobic self-cleaning coating in this experiment has strong light transmittance and hardly affects the power generation efficiency of the photovoltaic panel, indicating that the coating has good light transmittance.

[0125] The above tests further demonstrate that the super-hydrophobic self-cleaning coating provided by this technology has good light transmittance and stability, and effectively solves the problems of low light transmittance and insufficient durability of existing super-hydrophobic self-cleaning coatings.

[0126] It should be noted that, according to the above-mentioned embodiments of the present technology, those skilled in the art can fully implement the full scope of the independent claims and dependent rights of the present invention, and the implementation process and method are the same as the above-mentioned embodiments; and the parts not described in detail in the present technology belong to the well-known technology in the art.

[0127] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0128] The parts not elaborated in detail in the description of the present invention belong to the known technology in the art. The above embodiments are provided only for the purpose of describing the present invention, and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. Various equivalent substitutions and modifications made without departing from the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A modified gas-phase nano-SiO2, characterized in that: The modified gas-phase nano-SiO2 nanoparticles have long-chain hydrocarbons on their surfaces and contain unsaturated double bonds; wherein the number of carbon atoms in the long-chain hydrocarbons is 5-50.

2. The modified gas-phase nano-SiO2 according to claim 1, characterized in that: The molecular structure formula of the modified gas-phase nano-SiO2 is as follows: ； Where n is 5~50.

3. The modified gas-phase nano-SiO2 according to claim 2, characterized in that: The molecular structure formula of the modified gas-phase nano-SiO2 is: ； or ; or .

4. The method for preparing modified gas-phase nano-SiO2 according to any one of claims 1 to 3, characterized in that: The steps include: S11: heating ethanol, ammonia water and TEOS and mixing them uniformly; S12: Add hydrophilic gas-phase nano-SiO2 to the mixture obtained in step S11, add the organosilicon compound and KH-570 after mixing, mix them evenly, and react for a certain time; S13: centrifuging, washing, drying and grinding the solution obtained in step S12 to obtain modified gas-phase nano-SiO2; The ratio of hydrophilic gas-phase nano-SiO2 and TEOS added is 0.1~0.2g / ml; The volume ratio of ethanol, ammonia water and TEOS is 150-260:6-10:16-25; The mass ratio of the hydrophilic gas-phase nano-SiO2, the organic silicon compound and KH-570 is 1:1:1-2:1:

1.

5. A method for preparing a SiO2 / VTES / MMA composite emulsion, characterized in that: Using the modified gas-phase nano-SiO2 according to any one of claims 1 to 3, the preparation method of the SiO2 / VTES / MMA composite emulsion comprises the following steps: S21: dissolving the reaction monomers MMA and VTES, the crosslinking agent DEGDA, the emulsifier AEO-9 and AES in deionized water, and mixing them evenly to obtain a homogeneous emulsion; S22: adding an initiator to the homogeneous emulsion obtained in step S1, heating and stirring; S23: Add modified gas-phase nano-SiO2 to the solution obtained in step S2, continue heating and stirring, and react for a certain period of time to obtain a SiO2 / VTES / MMA composite emulsion; The mass ratio of MMA to VTES is 2-3; The mass ratio of the MMA to the modified gas-phase nano-SiO2 is 7-16; The mass ratio of the initiator to the modified gas-phase nano-SiO2 is 7-20.

6. A SiO2 / VTES / MMA composite emulsion, characterized in that: The composite emulsion is prepared by the method for preparing the SiO2 / VTES / MMA composite emulsion according to claim 5.

7. A method for preparing a super hydrophobic self-cleaning coating, characterized in that: Using the SiO2 / VTES / MMA composite emulsion according to claim 6, the method for preparing the super hydrophobic self-cleaning coating comprises the following steps: S31: coating the SiO2 / VTES / MMA composite emulsion onto a glass substrate; the thickness of the coating obtained after coating is 1-2 mm; S32: The coated glass substrate is baked, and a super-hydrophobic self-cleaning coating is obtained after cooling.

8. The method for preparing a super hydrophobic self-cleaning coating according to claim 7, characterized in that: Before coating, the glass substrate is cleaned; the cleaning process is to clean the glass substrate in acetone, ethanol and deionized water in sequence.

9. The method for preparing a super hydrophobic self-cleaning coating according to claim 7, characterized in that: After the cleaning process, the glass substrate is subjected to a secondary cleaning process; the secondary cleaning process is to immerse the cleaned glass substrate in a mixed solution of concentrated sulfuric acid and hydrogen peroxide; The temperature of the mixed solution of concentrated sulfuric acid and hydrogen peroxide is 45-55°C; And / or, the volume ratio of concentrated sulfuric acid to hydrogen peroxide in the mixed solution is 2:1 to 5:

1.

10. The method for preparing a super hydrophobic self-cleaning coating according to claim 7, characterized in that: The coating process in step S31 is a multiple-time coating process.

11. The method for preparing a super hydrophobic self-cleaning coating according to claim 7, characterized in that: The coating treatment is carried out by spraying with a spray gun, the nozzle is about 15 cm to 20 cm away from the substrate, and the spraying time is 2 to 3 seconds.

Images