Preparation method of anti-counterfeiting self-cleaning coating on surface of toughened glass

Abstract

The invention relates to the technical field of surface treatment, and discloses a preparation method of an anti-counterfeiting self-cleaning coating on the surface of tempered glass. Comprising the following steps: 1) mixing a silanized carbon quantum dot water concentrated solution with octadecyltrichlorosilane, carrying out a reaction, hydrolyzing octadecyltrichlorosilane into octadecylsilanetriol, carrying out polycondensation to form a polymer net structure, doping silanized carbon quantum dots into the polymer net structure, adding n-hexane, and finishing the reaction to obtain an anti-counterfeiting self-cleaning coating; 2, the anti-fake self-cleaning coating is sprayed to the surface of the tempered glass, standing and drying are conducted, and the anti-fake self-cleaning coating is obtained.The mixed reaction solution of the silanized carbon quantum dot water concentrated solution and octadecyl trichlorosilane serves as the coating, and the coating with the anti-fake function and the self-cleaning function can be formed on the surface of the tempered glass.

Description

Technical Field

[0001] The present invention relates to the technical field of surface treatment, and in particular to a preparation method of an anti-counterfeiting and self-cleaning coating on the surface of tempered glass. Background Art

[0002] As a widely popular glass product, tempered glass has the characteristics of high safety, high mechanical strength, high thermal shock resistance, etc., and is widely used in modern life in fields such as home decoration, construction, and automobiles. However, during use, the surface of tempered glass is easily contaminated by dust accumulation, so its surface needs to be frequently cleaned. In addition, there are also some counterfeit and shoddy products of low quality and passing off inferior goods as good ones in the tempered glass market, which seriously damages the interests of consumers and regular merchants.

[0003] Octadecyltrichlorosilane (OTS) is a commonly used organosilane derivative. It has been found that the product formed by the hydrolysis reaction of OTS with a certain amount of water and sprayed on the surface of substrates such as glass, wood, and fiber cloth can form a superhydrophobic self-cleaning coating. At the same time, as an environmentally friendly fluorescent nanomaterial, carbon quantum dots are easily soluble in water and have the advantages of low cost, high fluorescence yield, and good biocompatibility. They have gradually become a hot spot in the research field of luminescent materials and have important application value in the field of anti-counterfeiting (CN202311383341.7).

[0004] In view of this, if OTS and carbon quantum dots are compounded and applied to tempered glass, it is expected to endow it with both superhydrophobic self-cleaning function and fluorescence anti-counterfeiting function, thereby effectively combating counterfeit and shoddy products. However, according to our previous research results, it is further found that the self-cleaning effects of the anti-counterfeiting and self-cleaning coatings on the surface of tempered glass prepared by reacting different volumes of silylated carbon quantum dot mother liquor with a certain amount of OTS are different. Therefore, how to ensure the anti-counterfeiting function while improving the self-cleaning performance of the surface of tempered glass is an urgent problem to be solved. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a preparation method of an anti-counterfeiting and self-cleaning coating on the surface of tempered glass. The present invention uses a mixed reaction solution of silylated carbon quantum dot water concentrate and octadecyltrichlorosilane as a coating material, which can form a coating with both anti-counterfeiting function and self-cleaning function on the surface of tempered glass.

[0006] The specific technical solution of the present invention is: a preparation method of an anti-counterfeiting and self-cleaning coating on the surface of tempered glass, which specifically includes the following steps: 1) Mix the concentrated aqueous solution of silylated carbon quantum dots with a concentration of 5 - 9 mol / L with octadecyltrichlorosilane (OTS) and react. After octadecyltrichlorosilane hydrolyzes into octadecylsilanetriol (PODS), it polycondenses to form a polymer network structure, and the silylated carbon quantum dots are doped in the polymer network structure. After adding n - hexane to end the reaction, an anti - counterfeiting self - cleaning coating is obtained.

[0007] The concentrated aqueous solution of silylated carbon quantum dots uses silylated carbon quantum dots as the solute and water as the solvent. The carbon quantum dots have the property of fluorescence anti - counterfeiting. After mixing the concentrated aqueous solution of silylated carbon quantum dots with octadecyltrichlorosilane, octadecyltrichlorosilane can undergo a hydrolysis reaction with trace amounts of water. The present invention discovers that the difference between octadecyltrichlorosilane and other types of chlorosilane derivatives is that: traditional chlorosilane derivatives will undergo violent reactions and form large aggregates after contacting with trace amounts of water, and such large aggregates are not conducive to the preparation of self - cleaning coatings; but we find that the C18 long - chain alkyl group of octadecyltrichlorosilane will reduce the reaction rate when exposed to water or moisture, indicating that the hydrolysis reaction of octadecyltrichlorosilane is kinetically controllable. Therefore, the present invention can control the hydrolysis reaction of octadecyltrichlorosilane with a certain amount of water to reduce the formation of large aggregates, thus being conducive to the preparation of anti - counterfeiting self - cleaning coatings.

[0008] The reaction principle of the above step 1) is as follows: After octadecyltrichlorosilane undergoes a hydrolysis reaction with a certain amount of water in the concentrated aqueous solution of silylated carbon quantum dots, octadecylsilanetriol (PODS) is generated. One end of PODS is a hydroxyl group, which is a polar group and a hydrophilic end, and the other end is a long - chain alkyl group, which is a non - polar group and a hydrophobic end. Through the polycondensation between the hydroxyl groups of PODS, the silylated carbon quantum dots are doped in the network structure formed by the polycondensation of PODS.

[0009] 2) Spray the anti - counterfeiting self - cleaning coating on the surface of tempered glass and let it stand for drying to form an anti - counterfeiting self - cleaning coating.

[0010] In step 2), after spraying the coating on the surface of tempered glass, a nanolayered structure with one hydrophobic group and one hydrophilic group doped with silylated carbon quantum dots is formed. Since the surface of tempered glass is a hydrophilic substrate, the hydrophilic end of the nanolayered structure will gradually face the surface of tempered glass and be adsorbed onto the tempered glass substrate through hydrogen - bond interaction, fixing the nanolayered structure on the surface of tempered glass. The hydrophobic end of the nanolayered structure faces outward to form an anti - counterfeiting self - cleaning coating.

[0011] Preferably, in step 1), the volume ratio of the concentrated aqueous solution of silylated carbon quantum dots to octadecyltrichlorosilane is (10 - 15):500.

[0012] The present invention finds that the volume ratio of the silylated carbon quantum dot aqueous concentrate to octadecyltrichlorosilane has an important influence on the performance of the final coating. If the volume of the silylated carbon quantum dot aqueous concentrate is too small, the amount of water contained is too small, the amount of PODS hydrolyzed from OTS is too small, and the amount of the nano-layered structure formed by PODS is too small, which cannot meet the rough structure required for the self-cleaning coating, resulting in poor self-cleaning effect; conversely, if the volume of the silylated carbon quantum dot aqueous concentrate is too large, the amount of water contained is too large, the amount of PODS hydrolyzed from OTS is too large, and excessive polycondensation reaction of PODS occurs, resulting in large aggregates, and the self-cleaning effect will also deteriorate.

[0013] Preferably, in step 1), the preparation method of the silylated carbon quantum dot aqueous concentrate is as follows: Dissolve citric acid in water, add N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS), heat for reaction, and after the reaction is completed, cool and concentrate the product to obtain the silylated carbon quantum dot aqueous concentrate.

[0014] Preferably, in step 1), the temperature of the heating reaction is 160-200 °C, and the time is 10-14 h.

[0015] Preferably, in step 1), the mass ratio range of citric acid to N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane is 1:10-15.

[0016] Preferably, in step 1), the mixing is carried out by ultrasonic dispersion, and the ultrasonic dispersion time is 10-30 min.

[0017] Preferably, in step 1), the reaction is carried out under semi-sealed conditions.

[0018] The present invention finds that HCl gas is generated during the hydrolysis of OTS. Part of the HCl gas will dissolve in water, but there is still part of the HCl gas escaping. If the reaction vessel is completely sealed, there will be a certain danger. However, the hydrolysis of OTS is affected by the moisture in the air, and it is not suitable to directly open the reaction vessel. Therefore, the reaction needs to be carried out under semi-sealed conditions.

[0019] Preferably, in step 1), the reaction time is 1.5-3 h.

[0020] Preferably, in step 1), the volume ratio of octadecyltrichlorosilane to n-hexane is 1:(5-15).

[0021] Preferably, in step 2), the surface of the tempered glass is pre-cleaned.

[0022] Pre-cleaning the tempered glass to remove the dust and oil on the surface of the tempered glass is beneficial to preparing the anti-counterfeiting self-cleaning coating on the surface of the tempered glass.

[0023] More preferably, the pre - cleaning is ultrasonic cleaning with water and ethanol for 10 - 30 min respectively, and then drying at 50 - 70 °C.

[0024] Preferably, in step 2), the anti - counterfeiting self - cleaning coating is ultrasonically treated before spraying.

[0025] More preferably, the time of the ultrasonic treatment is 10 - 30 min.

[0026] Preferably, in step 2), the distance between the spray gun and the surface of the tempered glass during spraying is 10 - 30 cm, the spraying time is 1 - 3 s; the spraying amount is 0.1 - 0.3 ml / cm 2 .

[0027] Preferably, in step 2), the time of static drying is 10 - 14 h.

[0028] Compared with the prior art, the beneficial effects of the present invention are: (1) The carbon quantum dots used in the present invention have the advantages of low cost and high fluorescence yield; at the same time, OTS is a common chlorosilane derivative and is easy to obtain; the preparation method of the anti - counterfeiting self - cleaning coating is simple and easy to use.

[0029] (2) The present invention prepares an anti - counterfeiting self - cleaning coating by doping silylated carbon quantum dots into a layered structure with one hydrophilic end and one hydrophobic end formed by the hydrolysis and polycondensation of OTS. Applied on the surface of tempered glass, it endows the surface of tempered glass with anti - counterfeiting and self - cleaning properties, increases the application of tempered glass in the fields of home decoration, etc., and effectively combats counterfeit and shoddy products. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the preparation principle diagram of the anti - counterfeiting self - cleaning coating in the present invention.

[0031] Figure 2 It is the fluorescence anti - counterfeiting effect diagram of the anti - counterfeiting self - cleaning coating on the surface of the tempered glass prepared in Example 3.

[0032] Figure 3 It is the electron microscope images of the anti - counterfeiting self - cleaning coating in Example 3 with magnifications of 5000 times (a) and 50000 times (b).

[0033] Figure 4 It is the contact angle picture of the anti - counterfeiting self - cleaning coating prepared in Comparative Example 1.

[0034] Figure 5 It is the contact angle picture of the anti - counterfeiting self - cleaning coating prepared in Example 1.

[0035] Figure 6 It is the contact angle picture of the anti - counterfeiting self - cleaning coating prepared in Example 2.

[0036] Figure 7 Contact angle pictures of the anti-counterfeiting and self-cleaning coating prepared in Comparative Example 2.

[0037] Figure 8 Contact angle pictures of the anti-counterfeiting and self-cleaning coating prepared in Comparative Example 3.

[0038] Figure 9 Contact angle pictures of the anti-counterfeiting and self-cleaning coating prepared in Example 3.

[0039] Figure 10 Pictures of the repelling phenomenon of the anti-counterfeiting and self-cleaning coating prepared in Example 3 against various liquids.

[0040] Figure 11 Pictures of the self-cleaning performance of tempered glass (a-c) and the anti-counterfeiting and self-cleaning coating (d-f) prepared in Example 3. Detailed implementation manners

[0041] The present invention will be further described below in conjunction with examples.

[0042] General example A method for preparing an anti-counterfeiting and self-cleaning coating on the surface of tempered glass, which specifically includes the following steps: 1) Mix and react a silanized carbon quantum dot water concentrate with a concentration of 5-9 mol / L and octadecyltrichlorosilane (OTS). After octadecyltrichlorosilane is hydrolyzed into octadecylsilanetriol (PODS), it undergoes polycondensation to form a polymer network structure, and the silanized carbon quantum dots are doped in the polymer network structure. After adding n-hexane to end the reaction, an anti-counterfeiting and self-cleaning coating is obtained; wherein, the volume ratio of the silanized carbon quantum dot water concentrate to octadecyltrichlorosilane is (10-15):500.

[0043] In some preferred implementation cases, in step 1), the preparation method of the silanized carbon quantum dot water concentrate is as follows: Dissolve citric acid in water, add N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS), heat and react. After the reaction ends, cool and concentrate the product to obtain a silanized carbon quantum dot water concentrate.

[0044] In some more preferred implementation cases, in step 1), the temperature of the heating reaction is 160-200 °C, and the time is 10-14 h.

[0045] In some more preferred implementation cases, in step 1), the mass ratio range of citric acid to N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane is 1:10-15.

[0046] In some preferred embodiments, in step 1), the mixing is carried out by ultrasonic dispersion, and the ultrasonic dispersion time is 10 - 30 min.

[0047] In some preferred embodiments, in step 1), the reaction is carried out under semi-sealed conditions.

[0048] In some preferred embodiments, in step 1), the reaction time is 1.5 - 3 h.

[0049] In some preferred embodiments, in step 1), the volume ratio of octadecyltrichlorosilane to n-hexane is 1:(5 - 15).

[0050] 2) Spray the anti-counterfeiting self-cleaning coating on the surface of tempered glass, and let it stand for drying to form an anti-counterfeiting self-cleaning coating.

[0051] In some preferred embodiments, in step 2), the surface of the tempered glass is pre-cleaned.

[0052] In some more preferred embodiments, the pre-cleaning is to ultrasonically clean with water and ethanol for 10 - 30 min respectively, and then dry at 50 - 70 °C.

[0053] In some preferred embodiments, in step 2), the anti-counterfeiting self-cleaning coating is ultrasonically treated before spraying.

[0054] In some more preferred embodiments, the time of the ultrasonic treatment is 10 - 30 min.

[0055] In some preferred embodiments, in step 2), the distance between the spray gun and the surface of the tempered glass during spraying is 10 - 30 cm, the spraying time is 1 - 3 s; the spraying amount is 0.1 - 0.3 ml / cm 2 .

[0056] In some preferred embodiments, in step 2), the standing drying time is 10 - 14 h.

[0057] Specific examples and comparative examples Comparative example 1 (1) Ultrasonically wash the tempered glass in deionized water and ethanol for 20 min each, and dry it in an oven at 60 °C.

[0058] (2) Dissolve 0.425 g of citric acid in 5 ml of deionized water, and then mix it with 5 ml of N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS). Then transfer the mixed solution to the inner liner of a high-pressure hydrothermal reaction kettle, and then place the reaction kettle in an oven and heat it at 180 °C for 12 h. After the reaction is completed, wait for the product to cool to room temperature. Place the obtained mother liquor of silylated carbon quantum dots in an oven at 60 °C and dry it to 2 ml to obtain a water concentrate of silylated carbon quantum dots with a concentration of about 6.65 mol / L.

[0059] (3) Add 500 μl of OTS solution to a sample bottle, and then add 5 μl of the water concentrate of silylated carbon quantum dots. Cover the lid of the sample bottle but do not seal it. Ultrasonically disperse for 20 min, cover the lid of the sample bottle but do not seal it, react for 2 h, and add 5 ml of n-hexane to end the reaction to obtain an anti-counterfeiting self-cleaning coating.

[0060] (4) Ultrasonically treat the obtained anti-counterfeiting self-cleaning coating for 20 min, and then spray it at a distance of 20 cm from the tempered glass for 2 s, with a spraying amount of 0.2 ml / cm 2 , and let it stand and dry for 12 h to obtain an anti-counterfeiting self-cleaning tempered glass.

[0061] Example 1 (1) Ultrasonically wash the tempered glass in deionized water and ethanol for 20 min each, and dry it in an oven at 60 °C.

[0062] (2) Dissolve 0.425 g of citric acid in 5 ml of deionized water, and then mix it with 5 ml of N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS). Then transfer the mixed solution to the inner liner of a high-pressure hydrothermal reaction kettle, and then place the reaction kettle in an oven and heat it at 180 °C for 12 h. After the reaction is completed, wait for the product to cool to room temperature. Place the obtained mother liquor of silylated carbon quantum dots in an oven at 60 °C and dry it to 2 ml to obtain a water concentrate of silylated carbon quantum dots with a concentration of about 6.65 mol / L.

[0063] (3) Add 500 μl of OTS solution to a sample bottle, and then add 10 μl of the water concentrate of silylated carbon quantum dots. Cover the lid of the sample bottle but do not seal it. Ultrasonically disperse for 20 min, cover the lid of the sample bottle but do not seal it, react for 2 h, and add 5 ml of n-hexane to end the reaction to obtain an anti-counterfeiting self-cleaning coating.

[0064] (4) Ultrasonically treat the obtained anti-counterfeiting self-cleaning coating for 20 min, and then spray it at a distance of 20 cm from the tempered glass for 2 s, with a spraying amount of 0.2 ml / cm 2 , and let it stand and dry for 12 h to obtain an anti-counterfeiting self-cleaning tempered glass.

[0065] Example 2 (1) Ultrasonically wash the tempered glass in deionized water and ethanol for 20 min each, and dry it in an oven at 60 °C.

[0066] (2) Dissolve 0.425 g of citric acid in 5 ml of deionized water, and then mix it with 5 ml of N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS). Then transfer the mixed solution to the inner liner of a high-pressure hydrothermal reaction kettle, and place the reaction kettle in an oven. Heat it at 180 °C for 12 h. After the reaction is completed, wait for the product to cool to room temperature. Place the obtained silanized carbon quantum dot mother liquor in an oven at 60 °C and dry it to 2 ml to obtain a water concentrate of silanized carbon quantum dots with a concentration of approximately 6.65 mol / L.

[0067] (3) Add 500 μl of OTS solution to a sample bottle, and then add 15 μl of the water concentrate of silanized carbon quantum dots. Cover the lid of the sample bottle but do not seal it. Ultrasonically disperse for 20 min, cover the lid of the sample bottle but do not seal it, react for 2 h, and add 5 ml of n-hexane to end the reaction to obtain an anti-counterfeiting self-cleaning coating.

[0068] (4) Ultrasonically wash the obtained anti-counterfeiting self-cleaning coating for 20 min, and then spray it at a distance of 20 cm from the tempered glass for 2 s, with a spraying amount of 0.2 ml / cm 2 , and let it stand and dry for 12 h to obtain anti-counterfeiting self-cleaning tempered glass.

[0069] Comparative Example 2 (1) Ultrasonically wash the tempered glass in deionized water and ethanol for 20 min each, and dry it in an oven at 60 °C.

[0070] (2) Dissolve 0.425 g of citric acid in 5 ml of deionized water, and then mix it with 5 ml of N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS). Then transfer the mixed solution to the inner liner of a high-pressure hydrothermal reaction kettle, and place the reaction kettle in an oven. Heat it at 180 °C for 12 h. After the reaction is completed, wait for the product to cool to room temperature. Place the obtained silanized carbon quantum dot mother liquor in an oven at 60 °C and dry it to 2 ml to obtain a water concentrate of silanized carbon quantum dots with a concentration of approximately 6.65 mol / L.

[0071] (3) Add 500 μl of OTS solution to a sample bottle, and then add 20 μl of the water concentrate of silanized carbon quantum dots. Cover the lid of the sample bottle but do not seal it. Ultrasonically disperse for 20 min, cover the lid of the sample bottle but do not seal it, react for 2 h, and add 5 ml of n-hexane to end the reaction to obtain an anti-counterfeiting self-cleaning coating.

[0072] (4) Ultrasonically wash the obtained anti-counterfeiting self-cleaning coating for 20 min, and then spray it at a distance of 20 cm from the tempered glass for 2 s, with a spraying amount of 0.2 ml / cm 2, leave it to stand and dry for 12 h to obtain the anti-counterfeiting self-cleaning toughened glass.

[0073] Comparative Example 3 (1) Ultrasonically wash the toughened glass in deionized water and ethanol for 20 min each, and dry it in an oven at 60 °C.

[0074] (2) Dissolve 0.425 g of citric acid in 5 ml of deionized water, and then mix it with 5 ml of N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS). Then transfer the mixed solution to the inner liner of a high-pressure hydrothermal reaction kettle, and then place the reaction kettle in an oven and heat it at 180 °C for 12 h. After the reaction ends, wait for the product to cool to room temperature, and place the obtained silanized carbon quantum dot mother liquor in an oven at 60 °C and dry it to 2 ml to obtain a water concentrate of silanized carbon quantum dots with a concentration of about 6.65 mol / L.

[0075] (3) Add 500 μl of OTS solution to a sample bottle, and then add 10 μl of the water concentrate of silanized carbon quantum dots. Cover the lid of the sample bottle but do not seal it. Ultrasonically disperse for 20 min, cover the lid of the sample bottle but do not seal it, react for 1 h, and add 5 ml of n-hexane to end the reaction to obtain the anti-counterfeiting self-cleaning coating.

[0076] (4) Ultrasonically wash the obtained anti-counterfeiting self-cleaning coating for 20 min, and then spray it at a distance of 20 cm from the toughened glass for 2 s, with a spraying amount of 0.2 ml / cm 2 , leave it to stand and dry for 12 h to obtain the anti-counterfeiting self-cleaning toughened glass.

[0077] Example 3 (1) Ultrasonically wash the toughened glass in deionized water and ethanol for 20 min each, and dry it in an oven at 60 °C.

[0078] (2) Dissolve 0.425 g of citric acid in 5 ml of deionized water, and then mix it with 5 ml of N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS). Then transfer the mixed solution to the inner liner of a high-pressure hydrothermal reaction kettle, and then place the reaction kettle in an oven and heat it at 180 °C for 12 h. After the reaction ends, wait for the product to cool to room temperature, and place the obtained silanized carbon quantum dot mother liquor in an oven at 60 °C and dry it to 2 ml to obtain a water concentrate of silanized carbon quantum dots with a concentration of about 6.65 mol / L.

[0079] (3) Add 500 μl of OTS solution to a sample bottle, and then add 10 μl of the water concentrate of silanized carbon quantum dots. Cover the lid of the sample bottle but do not seal it. Ultrasonically disperse for 20 min, cover the lid of the sample bottle but do not seal it, react for 3 h, and add 5 ml of n-hexane to end the reaction to obtain the anti-counterfeiting self-cleaning coating.

[0080] (4) Ultrasonicate the obtained anti-counterfeiting self-cleaning coating for 20 min, then spray it at a distance of 20 cm from the tempered glass for 2 s, and the spraying amount is 0.2 ml / cm 2 , leave it to stand and dry for 12 h to obtain anti-counterfeiting self-cleaning tempered glass.

[0081] Performance testing and characterization Figure 1 This is the schematic diagram for the preparation of the anti-counterfeiting self-cleaning coating in the present invention. As Figure 1 shown, first, a hydrothermal method is adopted. Using citric acid as the carbon source and N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane (AEAPMS) as the passivator, silylated carbon quantum dots are prepared in one step. After the dehydration, polymerization, and carbonization processes of citric acid, a carbon core is formed. The amino functional group of AEAPMS undergoes an amidation reaction with the carboxyl group on the surface of the carbon core, causing the crystal nucleus to grow into silylated carbon quantum dots. Then, by mixing OTS with the aqueous concentrated solution of silylated carbon quantum dots, OTS undergoes a hydrolysis reaction with a certain amount of water in the aqueous concentrated solution of silylated carbon quantum dots to generate PODS and HCl gas. One end of PODS is a hydroxyl group, which is a polar group and is the hydrophilic end, and the other end is a long-chain alkyl group, which is a non-polar group and is the hydrophobic end. The solubility of HCl gas in water is very high, and it will provide a weak acid environment for the solution. In the weak acid environment, the Si-(O-CH3) at the outer end of the silylated carbon quantum dots will hydrolyze into Si-(OH)3, and under the action of van der Waals forces and hydrophobic / hydrophilic effects, it will gradually approach the hydroxyl group end of PODS from randomly dispersed around PODS and adsorb around the hydroxyl group of PODS through hydrogen bonding. PODS self-assembles under the action of van der Waals forces and hydrophobic / hydrophilic effects to form a layer-like micelle with an oriented arrangement. In the weak acid environment, a polycondensation reaction occurs between the hydroxyl groups at the hydrophilic ends of PODS to form Si-O-Si covalent bonds, so that the silylated carbon quantum dots around the hydroxyl group are doped into the network structure formed by the polycondensation of PODS. The hydrophobic ends of PODS are connected by van der Waals forces, and finally, a nano-layered structure with one end having hydrophilic groups and the other end having hydrophobic groups doped with silylated carbon quantum dots is formed to obtain the anti-counterfeiting self-cleaning coating.

[0082] Figure 2 This is the fluorescence anti-counterfeiting effect diagram of the anti-counterfeiting self-cleaning coating on the surface of the tempered glass prepared in Example 3. As Figure 2 shown, under ultraviolet light with a wavelength of 365 nm, the coating has a fluorescence anti-counterfeiting effect, indicating that the carbon quantum dots have been successfully doped into the nano-layered structure formed by the hydrolysis and polycondensation of OTS, providing a fluorescence anti-counterfeiting effect for the coating.

[0083] Figure 3 These are the electron microscope images of the anti-counterfeiting self-cleaning coating prepared in Example 3 magnified 5000 times (a) and 50000 times (b). From Figure 3It can be seen that the coating is mainly composed of irregularly overlapping nanosheets with a thickness of about 60 nm. The above-mentioned rough micro-nano structure is due to the formation of PODS after the hydrolysis of OTS. One end of PODS is a hydroxyl group, which is a polar group and a hydrophilic end, and the other end is a long-chain alkyl group, which is a non-polar group and a hydrophobic end. Under the action of van der Waals forces and hydrophobic / hydrophilic effects, the polar groups gradually approach each other, and the non-polar groups gradually approach each other, forming a layered micelle with a directional arrangement. In a weak acid environment, a polycondensation reaction occurs between the hydroxyl groups of PODS, and the silylated carbon quantum dots are doped into the network structure formed by the polycondensation of PODS. The long-chain alkyl groups of PODS are connected by van der Waals forces, and finally a nano-layered structure is formed.

[0084] Table 1 Case Contact Angle (°) Rolling Angle (°) Comparative Example 1 144.0 ＞10 Example 1 153.2 7.8 Example 2 152.4 7.1 Comparative Example 2 146.7 ＞10 Comparative Example 3 148.6 ＞10 Example 3 153.3 6.1 Figures 4 - 9 They are the contact angle pictures of the anti-counterfeiting and self-cleaning coatings on the surface of tempered glass prepared in each example and comparative example. Table 1 shows the contact angle and rolling angle parameters of the anti-counterfeiting and self-cleaning coatings on the surface of tempered glass prepared in each example and comparative example. In the present invention, a contact angle measuring instrument is used to measure the product. The sample is placed on the sample stage of the contact angle measuring instrument, and the syringe for sucking deionized water is fixed on the measuring instrument. The focal length and the sample position are adjusted to make the imaging clear. A water droplet with a volume of 4 μl is taken, and the contact angle is measured at least at 3 points on the surface of each sample, and the average value of the results is taken. A water droplet with a volume of 10 μl is taken, and the platform on which the sample is placed is slowly tilted until the water droplet rolls or moves. The tilt angle of the platform is the rolling angle, and the rolling angle is measured at least at 3 points on the surface of each sample, and the average value of the results is taken.

[0085] OTS hydrolysis is a process that is sensitive to the volume of the silanized carbon quantum dot aqueous concentrate. Comparative Examples 1-2 and Examples 1-2 illustrate that the reaction of OTS with a trace amount or an excessive amount of the silanized carbon quantum dot aqueous concentrate will affect the self-cleaning performance of the anti-counterfeiting self-cleaning coating. In Comparative Example 1, OTS undergoes a hydrolysis reaction with water in a trace amount of the silanized carbon quantum dot aqueous concentrate (5 μl), and too little PODS is generated by the reaction, which is not enough to form the micro-nano structure required for the self-cleaning coating. Therefore, its self-cleaning effect is relatively poor. In Comparative Example 2, OTS undergoes a hydrolysis reaction with water in an excessive amount of the silanized carbon quantum dot aqueous concentrate (20 μl), and too much PODS and HCl gas are generated, and the acidic environment of the solution becomes stronger, promoting the excessive polycondensation of PODS to form large aggregates, thereby reducing the self-cleaning performance of the anti-counterfeiting self-cleaning coating. On this basis, the reaction time of OTS with a certain amount of the silanized carbon quantum dot aqueous concentrate will also affect the self-cleaning performance of the anti-counterfeiting self-cleaning coating. In Comparative Example 3, the reaction time of the anti-counterfeiting self-cleaning coating is 1 h, its contact angle is less than 150°, and the rolling angle is greater than 10°, and the self-cleaning performance is poor because the reaction time is short, OTS is not completely hydrolyzed, little PODS is generated, and few nano-layered structures formed by PODS are insufficient to form the surface rough structure required for the self-cleaning coating, resulting in poor self-cleaning performance. In Example 3, the reaction time of the anti-counterfeiting self-cleaning coating is 3 h, its contact angle is greater than 150°, and the rolling is less than 10°, indicating that the hydrolysis degree of OTS is high, a large amount of PODS is generated, many nano-layered structures composed of PODS are formed, and the roughness of the coating formed on the surface of the tempered glass is good, and its self-cleaning performance is more excellent than that of the anti-counterfeiting self-cleaning coatings prepared in Example 1 and Comparative Example 3.

[0086] Figure 10 It shows that the anti-counterfeiting self-cleaning coating on the glass surface of the present invention is also repulsive to common liquids in life such as tea, soda, water, milk, etc., and can be widely used in life.

[0087] Figure 11 The self-cleaning effects of the surface of the tempered glass (a-c) and the anti-counterfeiting self-cleaning coating on the surface of the tempered glass prepared in Example 3 (d-f). After a small amount of water droplets flowed over the surface of the tempered glass, part of the sand was carried away. By continuing to increase the amount of water droplets, most of the sand was carried away. Since the surface of the tempered glass is a hydrophilic surface, there is still a small amount of sand residue on the surface; in Example 3, after a small amount of water droplets flowed over the anti-counterfeiting self-cleaning coating, it can be clearly seen that the water droplets carried away part of the sand, and there was no sand residue left in the area where the water droplets flowed. By continuing to increase the amount of water droplets, all the sand was carried away without residue, and the self-cleaning effect was good.

[0088] The raw materials and equipment used in the present invention are all common raw materials and equipment in the art without special instructions; the methods used in the present invention are all conventional methods in the art without special instructions.

[0089] The above are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of an anti-counterfeiting and self-cleaning coating on the surface of tempered glass, characterized in that Comprising: 1) Mix and react a silanized carbon quantum dot aqueous concentrate with a concentration of 5 - 9 mol / L with octadecyltrichlorosilane. After octadecyltrichlorosilane hydrolyzes into octadecylsilanetriol and then polycondenses to form a polymer network structure, the silanized carbon quantum dots are doped in the polymer network structure. After adding n - hexane to end the reaction, an anti - counterfeiting and self - cleaning coating is obtained. The volume ratio of the silanized carbon quantum dot aqueous concentrate to octadecyltrichlorosilane is (10 - 15):

500. 2) Spray the anti - counterfeiting and self - cleaning coating on the surface of tempered glass and let it stand for drying to form an anti - counterfeiting and self - cleaning coating.

2. The preparation method according to claim 1, wherein: In step 1), the preparation method of the silanized carbon quantum dot aqueous concentrate is: dissolve citric acid in water, add N-(β - aminoethyl - γ - aminopropyl)methyldimethoxysilane, heat for reaction. After the reaction ends, cool and concentrate the product to obtain the silanized carbon quantum dot aqueous concentrate.

3. The preparation method according to claim 2, characterized in that: In step 1), the temperature of the heating reaction is 160 - 200 °C and the time is 10 - 14 h; the mass ratio of citric acid to N-(β - aminoethyl - γ - aminopropyl)methyldimethoxysilane is 1:(10 - 15).

4. The preparation method according to any one of claims 1-3, characterized in that: In step 1), the mixing is carried out by ultrasonic dispersion, and the ultrasonic dispersion time is 10 - 30 min.

5. The preparation method according to claim 1, characterized in that: In step 1), the reaction is carried out under semi - sealed conditions; the reaction time is 1.5 - 3 h.

6. The preparation method according to claim 1 or 5, characterized in that: In step 1), the volume ratio of octadecyltrichlorosilane to n - hexane is 1:(5 - 15).

7. The preparation method according to claim 1, characterized in that: In step 2), the surface of the tempered glass is pre - cleaned.

8. The preparation method according to claim 1, characterized in that: In step 2), the anti - counterfeiting and self - cleaning coating is ultrasonically treated before spraying.

9. The preparation method according to claim 1, characterized in that: In step 2), the distance between the spray gun and the surface of the tempered glass during spraying is 10 - 30 cm, the spraying time is 1 - 3 s; the spraying volume is 0.1 - 0.3 ml / cm 2 .

10. The preparation method according to claim 1, characterized in that: In step 2), the standing and drying time is 10 - 14 h.

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