Preparation method of hydrophilic / hydrophobic SiO2 transparent high-adhesion wear-resistant super-hydrophobic coating for sandstone cultural relics

Abstract

The invention discloses a preparation method of a hydrophilic / hydrophobic SiO2 transparent high-adhesion wear-resistant super-hydrophobic coating for sandstone cultural relics. The preparation method comprises the following steps: 1, preparing hydrophilic SiO2 nanoparticles; 2, preparation of hydrophobic SiO2 nano particles; and 3, dispersing the hydrophilic / hydrophobic SiO2 nanoparticles prepared in the step 1 and the step 2 in an organic solvent, stirring and dispersing uniformly, adding a PDMS-CA mixture composed of polydimethylsiloxane and a curing agent, spraying the mixed liquid on the surface of a sandstone cultural relic, performing heat treatment, repeating the steps for several times, and drying at room temperature to obtain the hydrophilic / hydrophobic SiO2 transparent high-adhesion wear-resistant super-hydrophobic coating. A small amount of hydrophilic SiO2 nanoparticles are spontaneously attached to the surface of sandstone, are tightly linked with the sandstone through hydrogen bonds, and can form a stable rigid-flexible composite skeleton with polydimethylsiloxane to dissipate energy; the hydrophobic SiO2 nanoparticles are spontaneously close to the outer surface of the sandstone, so that the super-hydrophobicity of the coating is ensured; the prepared coating has transparency, super-hydrophobicity and mechanical durability.

Description

Technical Field

[0001] This invention pertains to cultural relic protection technology and relates to a coating preparation method, specifically a method for preparing a hydrophilic / hydrophobic SiO2 transparent, highly adhesive, wear-resistant, and superhydrophobic coating for sandstone cultural relics. Background Technology

[0002] Cultural relics are the material carriers of human civilization's evolution, bearing historical memory and cultural genes, and forming the foundation of national cultural identity. Among numerous cultural relics, the magnificent sandstone relics, due to their unique material and widespread distribution, face severe protection challenges. Their inherent porous structure and naturally exposed nature make sandstone relics susceptible to various water-related damages, making hydrophobic protection particularly important. With the development of bionics, superhydrophobic surfaces inspired by the lotus effect have attracted the attention of cultural relic conservationists. However, the micro / nanostructures of superhydrophobic surfaces are easily damaged under external forces, leading to the loss of superhydrophobicity, severely limiting practical applications. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a transparent, highly adhesive, wear-resistant, and superhydrophobic SiO2 coating for sandstone artifacts. While taking into account both transparency and superhydrophobicity, the method utilizes hydrophilic SiO2 to improve the adhesion between the coating and the substrate, thereby giving the coating good mechanical durability.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics includes the following steps:

[0006] Step 1: Preparation of hydrophilic SiO2 nanoparticles

[0007] γ-aminopropyltriethoxysilane dispersion was added dropwise to SiO2 / ethanol dispersion at a mass ratio of 1:(0.6~1). After reaction, hydrophilic SiO2 nanoparticles were obtained by centrifugation, washing with ethanol and drying.

[0008] Step 2: Preparation of hydrophobic SiO2 nanoparticles

[0009] An alkoxysiloxane / ethanol solution was added dropwise to the SiO2 dispersion at a mass ratio of 1:(2-5). After the reaction, hydrophobic SiO2 nanoparticles were obtained by centrifugation, washing with ethanol and drying.

[0010] Step 3: Mix the hydrophilic SiO2 nanoparticles prepared in Step 1 and the hydrophobic SiO2 nanoparticles prepared in Step 2 at a mass ratio of 1:(20-100) to obtain hydrophilic / hydrophobic SiO2 nanoparticles. Disperse the hydrophilic / hydrophobic SiO2 nanoparticles in an organic solvent to obtain a hydrophilic / hydrophobic SiO2 / organic solvent dispersion. After stirring evenly, add a PDMS-CA mixture composed of polydimethylsiloxane and a curing agent, and stir and disperse evenly to obtain a hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion. Spray the hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion onto the surface of sandstone artifacts and then perform heat treatment, forming a single spraying-heat treatment cycle. Repeat the above cycle several times and then dry at room temperature to obtain a transparent, highly adhesive, wear-resistant, superhydrophobic coating of hydrophilic / hydrophobic SiO2.

[0011] The mass ratio of the hydrophilic / hydrophobic SiO2 nanoparticles to the organic solvent is 1:(30-50); the mass ratio of the hydrophilic / hydrophobic SiO2 / organic solvent dispersion to the PDMS-CA mixture is 1:(0.05-0.2); and the mass ratio of polydimethylsiloxane to curing agent in the PDMS-CA mixture is 10:1.

[0012] Step 6: Fix the mesh onto the sandstone surface. First, spray the hydrophilic SiO2 nanoparticle / polydimethylsiloxane dispersion prepared in step 3 as the bottom layer. After standing at room temperature for 2 hours, spray the hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion prepared in step 4 as the middle layer. After standing at room temperature for 6 hours, spray the hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion prepared in step 5 as the top layer. Curing at room temperature yields a mesh-structured SiO2 transparent, high-adhesion, wear-resistant, superhydrophobic coating.

[0013] Furthermore, in step 1, the SiO2 / ethanol dispersion is obtained by ultrasonically dispersing SiO2 and ethanol at a mass ratio of (1:5) to (1:30).

[0014] Furthermore, the γ-aminopropyltriethoxysilane dispersion in step 1 is obtained by ultrasonically dispersing γ-aminopropyltriethoxysilane, ethanol and deionized water in a mass ratio of 1:(3-5):(0.5-1).

[0015] Furthermore, in step 1, the reaction temperature is 50–70°C, the reaction time is 2–4 h, the centrifugation speed is 6000–10000 rpm, the ethanol washing is performed 3–5 times, the drying temperature is 60–80°C, and the drying time is 2–4 h.

[0016] Furthermore, in step 2, the SiO2 dispersion is obtained by ultrasonically dispersing SiO2, ammonia, and deionized water in a mass ratio of 1:(1-1.5):(5-10).

[0017] Furthermore, in step 2, the alkoxysiloxane / ethanol solution is obtained by mixing alkoxysiloxane and ethanol solution at a mass ratio of 1:(30-100), wherein the alkoxysiloxane is a long-chain perfluoroalkyl alkoxysilane with ≥8 carbon atoms and a long-chain alkyl alkoxysilane with ≥12 carbon atoms.

[0018] Furthermore, the alkoxysiloxane includes perfluorodecyltriethoxysilane, perfluorooctyltriethoxysilane, dodecyltriethoxysilane, or hexadecyltriethoxysilane.

[0019] Furthermore, in step 2, the reaction temperature is 40–60°C, the reaction time is 12–36 h, the centrifugation speed is 6000–10000 rpm, the ethanol washing is performed 3–5 times, the drying temperature is 60–80°C, and the drying time is 2–4 h.

[0020] Furthermore, in step 3, the organic solvent is tetrahydrofuran, dimethylformamide, ethanol, or dichloromethane, and the stirring time is 15–30 min.

[0021] Furthermore, in step 3, the stirring time is 30-60 minutes, and the single spraying time is 1-3 seconds.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] In the coating structure, a small number of hydrophilic SiO2 nanoparticles spontaneously adhere to the sandstone substrate surface and form hydrogen bonds with the hydroxyl groups on the sandstone surface through their surface amino groups, significantly enhancing the interfacial bonding between the coating and the substrate. Furthermore, these hydrophilic SiO2 nanoparticles can also form a stable "SiO2–PDMS" rigid-flexible composite framework structure with polydimethylsiloxane (PDMS) through hydrolysis, which helps with stress transfer and energy dissipation, thereby improving the overall mechanical properties of the coating. A large number of hydrophobic SiO2 nanoparticles spontaneously adhere to the outer surface of the sandstone, further ensuring the excellent hydrophobic properties of the coating surface. When subjected to external abrasion or erosion, the outer layer of hydrophobic SiO2 nanoparticles first acts as a buffer and protector, and this layer-by-layer protection mechanism effectively prevents damage to the inner layer of hydrophilic SiO2 nanoparticles, thus significantly improving the mechanical durability and long-term stability of the coating. During the coating construction process, a phased process of 80°C heat treatment for 5 minutes after each spraying is adopted as a single cycle. After repeating this spraying-heat treatment cycle 3 times, the final drying and curing is completed at room temperature. This intermittent process effectively improves the hydrophobic properties of the coating. Attached Figure Description

[0024] Figure 1 A photograph of the original sandstone;

[0025] Figure 2 A photograph of sandstone modified with a hydrophilic / hydrophobic SiO2 transparent high-adhesion wear-resistant superhydrophobic coating for sandstone cultural relics prepared in Example 1 of this invention;

[0026] Figure 3 Photograph of sandstone modified with a hydrophilic / hydrophobic SiO2 transparent high-adhesion wear-resistant superhydrophobic coating for sandstone cultural relics prepared in Example 2 of the present invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1:

[0029] This embodiment provides a method for preparing a transparent, highly adhesive, wear-resistant, and superhydrophobic SiO2 coating for sandstone cultural relics, which specifically includes the following steps:

[0030] Step 1: Preparation of hydrophilic SiO2 nanoparticles: SiO2 and ethanol were ultrasonically dispersed at a mass ratio of 1:10 to obtain a SiO2 / ethanol dispersion. A γ-aminopropyltriethoxysilane dispersion, obtained by mixing γ-aminopropyltriethoxysilane, ethanol and deionized water at a mass ratio of 1:3.9:0.5, was added dropwise to the dispersion. The mass ratio of SiO2 / ethanol dispersion to γ-aminopropyltriethoxysilane dispersion was 1:0.6. After reacting at 60℃ for 3 hours, the mixture was centrifuged at 8000 rpm, washed three times with ethanol, and dried at 80℃ for 3 hours to obtain hydrophilic SiO2.

[0031] Step 2, Preparation of hydrophobic SiO2 nanoparticles: SiO2, ammonia, and deionized water were ultrasonically dispersed at a mass ratio of 1:1.2:5 to obtain a SiO2 dispersion. A perfluorodecyltriethoxysilane / ethanol solution, prepared by mixing perfluorodecyltriethoxysilane and ethanol solution at a mass ratio of 1:75, was added dropwise to the dispersion. The mass ratio of the SiO2 dispersion to the perfluorodecyltriethoxysilane / ethanol solution was 1:3.2. After reacting at 40℃ for 24 h, the mixture was centrifuged at 8000 rpm, washed three times with ethanol, and dried at 80℃ for 3 h to obtain hydrophobic SiO2.

[0032] Step 3: Mix the hydrophilic SiO2 prepared in Step 1 and the hydrophobic SiO2 nanoparticles prepared in Step 2 at a mass ratio of 1:20 to obtain hydrophilic / hydrophobic SiO2 nanoparticles. Disperse the hydrophilic / hydrophobic SiO2 nanoparticles in tetrahydrofuran to obtain a hydrophilic / hydrophobic SiO2 / tetrahydrofuran dispersion with a mass ratio of 1:44. After stirring for 30 min, add a PDMS-CA mixture composed of polydimethylsiloxane and curing agent at a mass ratio of 10:1. The mass ratio of the hydrophilic / hydrophobic SiO2 / tetrahydrofuran dispersion to the PDMS-CA mixture is 1:0.1. After stirring for 30 min, obtain a hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion. Spray the dispersion onto the surface of sandstone artifacts for 1 second, then heat-treat at 80°C for 5 min, forming a single spray-heat-treatment cycle. Repeat the above cycle 3 times, then dry at room temperature to obtain a transparent, highly adhesive, wear-resistant, superhydrophobic coating of hydrophilic / hydrophobic SiO2.

[0033] Figure 1 Original sandstone, Figure 2 The sandstone coated with a hydrophilic / hydrophobic SiO2 transparent high-adhesion wear-resistant superhydrophobic coating for sandstone cultural relics prepared in Example 1 showed no significant change in color compared to other sandstone artifacts. After being subjected to tape adhesion, sandpaper abrasion, gravel erosion, and acid rain / alkaline water erosion, its contact angle was still >150°, demonstrating excellent mechanical durability.

[0034] Example 2:

[0035] This embodiment provides a method for preparing a transparent, highly adhesive, wear-resistant, and superhydrophobic SiO2 coating for sandstone cultural relics, which specifically includes the following steps:

[0036] Step 1: Preparation of hydrophilic SiO2 nanoparticles: SiO2 and ethanol were ultrasonically dispersed at a mass ratio of 1:15 to obtain a SiO2 / ethanol dispersion. A γ-aminopropyltriethoxysilane dispersion, obtained by mixing γ-aminopropyltriethoxysilane, ethanol and deionized water at a mass ratio of 1:3:0.5, was added dropwise to the dispersion. The mass ratio of SiO2 / ethanol dispersion to γ-aminopropyltriethoxysilane dispersion was 1:0.8. After reacting at 60℃ for 3 hours, the mixture was centrifuged at 6000 rpm, washed three times with ethanol, and dried at 80℃ for 2 hours to obtain hydrophilic SiO2.

[0037] Step 2, Preparation of hydrophobic SiO2 nanoparticles: SiO2, ammonia, and deionized water were ultrasonically dispersed in a mass ratio of 1:1.3:6 to obtain a SiO2 dispersion. A perfluorooctyltriethoxysilane / ethanol solution, prepared by mixing perfluorooctyltriethoxysilane and ethanol solution in a mass ratio of 1:70, was added dropwise to the dispersion. The mass ratio of the SiO2 dispersion to the perfluorooctyltriethoxysilane / ethanol solution was 1:3.5. After reacting at 40℃ for 36 h, the mixture was centrifuged at 6000 rpm, washed three times with ethanol, and dried at 80℃ for 2 h to obtain hydrophobic SiO2.

[0038] Step 3: Mix the hydrophilic SiO2 prepared in Step 1 and the hydrophobic SiO2 nanoparticles prepared in Step 2 at a mass ratio of 1:100 to obtain hydrophilic / hydrophobic SiO2 nanoparticles. Disperse the hydrophilic / hydrophobic SiO2 nanoparticles in dimethylformamide to obtain a hydrophilic / hydrophobic SiO2 / dimethylformamide dispersion with a mass ratio of 1:40. After stirring for 45 min, add a PDMS-CA mixture composed of polydimethylsiloxane and curing agent at a mass ratio of 10:1. The mass ratio of the hydrophilic / hydrophobic SiO2 / dimethylformamide dispersion to the PDMS-CA mixture is 1:0.15. After stirring for 45 min, obtain a hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion. Spray the dispersion onto the surface of sandstone artifacts for 1 second, then heat-treat at 80°C for 5 min, forming a single spray-heat-treatment cycle. Repeat the above cycle 3 times, then dry at room temperature to obtain a transparent, highly adhesive, wear-resistant, superhydrophobic hydrophilic / hydrophobic SiO2 coating.

[0039] Figure 3 This is an example of a sandstone artifact coated with a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating, compared to the sandstone prepared in Example 2. Figure 1 The sandstone color did not change significantly, and its contact angle remained >150° after being subjected to tape adhesion, sandpaper abrasion, gravel erosion, and acid rain / alkaline water erosion, demonstrating excellent mechanical durability.

[0040] Example 3:

[0041] This embodiment provides a method for preparing a transparent, highly adhesive, wear-resistant, and superhydrophobic SiO2 coating for sandstone cultural relics, which specifically includes the following steps:

[0042] Step 1: Preparation of hydrophilic SiO2 nanoparticles: SiO2 and ethanol were ultrasonically dispersed at a mass ratio of 1:5 to obtain a SiO2 / ethanol dispersion. A γ-aminopropyltriethoxysilane dispersion, obtained by mixing γ-aminopropyltriethoxysilane, ethanol and deionized water at a mass ratio of 1:3:0.8, was added dropwise to the dispersion. The mass ratio of the SiO2 / ethanol dispersion to the γ-aminopropyltriethoxysilane dispersion was 1:0.6. After reacting at 70℃ for 2 hours, the mixture was centrifuged at 10000 rpm, washed 5 times with ethanol, and dried at 60℃ for 4 hours to obtain hydrophilic SiO2.

[0043] Step 2, Preparation of hydrophobic SiO2 nanoparticles: SiO2, ammonia, and deionized water were ultrasonically dispersed in a mass ratio of 1:1:5 to obtain a SiO2 dispersion. A dodecyltriethoxysilane / ethanol solution, prepared by mixing dodecyltriethoxysilane and ethanol solution in a mass ratio of 1:30, was added dropwise to the dispersion. The mass ratio of the SiO2 dispersion to the dodecyltriethoxysilane / ethanol solution was 1:2. After reacting at 60°C for 12 hours, the mixture was centrifuged at 10,000 rpm, washed five times with ethanol, and dried at 60°C for 4 hours to obtain hydrophobic SiO2.

[0044] Step 3: Mix the hydrophilic SiO2 prepared in Step 1 and the hydrophobic SiO2 nanoparticles prepared in Step 2 at a mass ratio of 1:50 to obtain hydrophilic / hydrophobic SiO2 nanoparticles. Disperse the hydrophilic / hydrophobic SiO2 nanoparticles in ethanol to obtain a hydrophilic / hydrophobic SiO2 / ethanol dispersion with a mass ratio of 1:30. After stirring for 60 min, add a PDMS-CA mixture composed of polydimethylsiloxane and curing agent at a mass ratio of 10:1. The mass ratio of the hydrophilic / hydrophobic SiO2 / ethanol dispersion to the PDMS-CA mixture is 1:0.05. After stirring for 60 min, obtain a hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion. Spray the dispersion onto the surface of the sandstone artifact for 2 s, then heat-treat at 80℃ for 5 min to form a single spray-heat-treatment cycle. Repeat the above cycle 3 times and then dry at room temperature to obtain a transparent, highly adhesive, wear-resistant, superhydrophobic coating of hydrophilic / hydrophobic SiO2.

[0045] Example 4:

[0046] This embodiment provides a method for preparing a transparent, highly adhesive, wear-resistant, and superhydrophobic SiO2 coating for sandstone cultural relics, which specifically includes the following steps:

[0047] Step 1: Preparation of hydrophilic SiO2 nanoparticles: SiO2 and ethanol were ultrasonically dispersed at a mass ratio of 1:30 to obtain a SiO2 / ethanol dispersion. A γ-aminopropyltriethoxysilane dispersion, obtained by mixing γ-aminopropyltriethoxysilane, ethanol and deionized water at a mass ratio of 1:5:1, was added dropwise to the dispersion. The mass ratio of the SiO2 / ethanol dispersion to the γ-aminopropyltriethoxysilane dispersion was 1:1. After reacting at 50℃ for 4 hours, the mixture was centrifuged at 9000 rpm, washed four times with ethanol, and dried at 70℃ for 3 hours to obtain hydrophilic SiO2.

[0048] Step 2, Preparation of hydrophobic SiO2 nanoparticles: SiO2, ammonia, and deionized water were ultrasonically dispersed in a mass ratio of 1:1.5:10 to obtain a SiO2 dispersion. A hexadecyltriethoxysilane / ethanol solution, obtained by mixing hexadecyltriethoxysilane and ethanol solution in a mass ratio of 1:100, was added dropwise to the dispersion. The mass ratio of the SiO2 dispersion to the hexadecyltriethoxysilane / ethanol solution was 1:5. After reacting at 50°C for 24 hours, the mixture was centrifuged at 9000 rpm, washed four times with ethanol, and dried at 70°C for 3 hours to obtain hydrophobic SiO2.

[0049] Step 3: Mix the hydrophilic SiO2 prepared in Step 1 and the hydrophobic SiO2 nanoparticles prepared in Step 2 at a mass ratio of 1:80 to obtain hydrophilic / hydrophobic SiO2 nanoparticles. Disperse the hydrophilic / hydrophobic SiO2 nanoparticles in dichloromethane to obtain a hydrophilic / hydrophobic SiO2 / dichloromethane dispersion. The mass ratio of hydrophilic / hydrophobic SiO2 nanoparticles to dichloromethane is 1:50. After stirring for 40 min, add a PDMS-CA mixture composed of polydimethylsiloxane and curing agent at a mass ratio of 10:1. The mass ratio of the hydrophilic / hydrophobic SiO2 / dichloromethane dispersion to the PDMS-CA mixture is 1:0.2. After stirring for 40 min, obtain a hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion. Spray the dispersion onto the surface of sandstone artifacts for 3 s, then heat-treat at 80℃ for 5 min, forming a single spray-heat-treatment cycle. Repeat the above cycle 3 times, then dry at room temperature to obtain a transparent, highly adhesive, wear-resistant, superhydrophobic coating of hydrophilic / hydrophobic SiO2.

Claims

1. A method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics, characterized in that, Includes the following steps: Step 1: Preparation of hydrophilic SiO2 nanoparticles γ-aminopropyltriethoxysilane dispersion was added dropwise to SiO2 / ethanol dispersion at a mass ratio of 1:(0.6~1). After reaction, hydrophilic SiO2 nanoparticles were obtained by centrifugation, washing with ethanol and drying. Step 2: Preparation of hydrophobic SiO2 nanoparticles An alkoxysiloxane / ethanol solution was added dropwise to the SiO2 dispersion at a mass ratio of 1:(2-5). After the reaction, hydrophobic SiO2 nanoparticles were obtained by centrifugation, washing with ethanol and drying. Step 3: Mix the hydrophilic SiO2 nanoparticles prepared in Step 1 and the hydrophobic SiO2 nanoparticles prepared in Step 2 at a mass ratio of 1:(20-100) to obtain hydrophilic / hydrophobic SiO2 nanoparticles. Disperse the hydrophilic / hydrophobic SiO2 nanoparticles in an organic solvent to obtain a hydrophilic / hydrophobic SiO2 / organic solvent dispersion. After stirring evenly, add a PDMS-CA mixture composed of polydimethylsiloxane and a curing agent, and stir and disperse evenly to obtain a hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion. Spray the hydrophilic / hydrophobic SiO2 nanoparticle / polydimethylsiloxane dispersion onto the surface of sandstone artifacts and then perform heat treatment, forming a single spraying-heat treatment cycle. Repeat the above cycle several times and then dry at room temperature to obtain a transparent, highly adhesive, wear-resistant, superhydrophobic coating of hydrophilic / hydrophobic SiO2. The mass ratio of the hydrophilic / hydrophobic SiO2 nanoparticles to the organic solvent is 1:(30-50); the mass ratio of the hydrophilic / hydrophobic SiO2 / organic solvent dispersion to the PDMS-CA mixture is 1:(0.05-0.2); and the mass ratio of polydimethylsiloxane to curing agent in the PDMS-CA mixture is 10:

1.

2. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 1, characterized in that, In step 1, the SiO2 / ethanol dispersion is obtained by ultrasonically dispersing SiO2 and ethanol at a mass ratio of (1:5) to (1:30).

3. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 1, characterized in that, The γ-aminopropyltriethoxysilane dispersion in step 1 is obtained by ultrasonically dispersing γ-aminopropyltriethoxysilane, ethanol and deionized water in a mass ratio of 1:(3-5):(0.5-1).

4. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 1, characterized in that, In step 1, the reaction temperature is 50–70°C, the reaction time is 2–4 h, the centrifugation speed is 6000–10000 rpm, the ethanol washing is performed 3–5 times, the drying temperature is 60–80°C, and the drying time is 2–4 h.

5. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 1, characterized in that, In step 2, the SiO2 dispersion is obtained by ultrasonically dispersing SiO2, ammonia and deionized water in a mass ratio of 1:(1-1.5):(5-10).

6. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 1, characterized in that, In step 2, the alkoxysiloxane / ethanol solution is obtained by mixing alkoxysiloxane and ethanol solution at a mass ratio of 1:(30-100), wherein the alkoxysiloxane is a long-chain perfluoroalkyl alkoxysilane with ≥8 carbon atoms and a long-chain alkyl alkoxysilane with ≥12 carbon atoms.

7. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 6, characterized in that, The alkoxysiloxanes include perfluorodecyltriethoxysilane, perfluorooctyltriethoxysilane, dodecyltriethoxysilane, or hexadecyltriethoxysilane.

8. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 1, characterized in that, In step 2, the reaction temperature is 40–60°C, the reaction time is 12–36 h, the centrifugation speed is 6000–10000 rpm, the ethanol washing is performed 3–5 times, the drying temperature is 60–80°C, and the drying time is 2–4 h.

9. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 1, characterized in that, In step 3, the organic solvent is tetrahydrofuran, dimethylformamide, ethanol, or dichloromethane, and the stirring time is 15–30 min.

10. The method for preparing a hydrophilic / hydrophobic SiO2 transparent, high-adhesion, wear-resistant, and superhydrophobic coating for sandstone cultural relics according to claim 1, characterized in that, In step 3, the stirring time is 30-60 minutes, and the single spraying time is 1-3 seconds.

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