Self-cleaning antibacterial antireflective coating based on sol-gel method

Abstract

This invention relates to a method for preparing and applying a self-cleaning antibacterial and antireflective coating based on the sol-gel method. The invention involves mixing nano-silica and nano-titanium dioxide prepared by the sol-gel method in a specific ratio, then applying the mixture to a glass substrate using a dip-coating method to obtain a nano-coating. The glass substrate is then heated and cured to obtain the self-cleaning, antibacterial, and antireflective nano-coating. The mixing of silica and titanium dioxide effectively increases the surface area of ​​titanium dioxide, resulting in a self-cleaning, antibacterial, and antireflective film. The introduction of titanium dioxide enhances the antibacterial properties of the antireflective coating, solving the problem of easy microbial contamination. Furthermore, the mixture of titanium dioxide and silica addresses the reduced light transmittance caused by a single titanium dioxide coating, giving the coating superhydrophilic properties and achieving a self-cleaning effect. The preparation process is simple and inexpensive, making it suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention belongs to the technical field of anti-reflective coatings, and relates to a self-cleaning antibacterial and anti-reflective coating based on the sol-gel method. Background Technology

[0002] With the rapid development and widespread use of electronic devices, glass components are being used extensively, leading to higher demands on their performance. Anti-reflective technology can improve the light transmittance of glass components and has the advantages of wide applicability and low cost. Anti-reflective technology typically uses the sol-gel method to prepare porous inorganic nanoparticle anti-reflective coatings, which can achieve high light transmittance and excellent anti-reflective performance. However, as the application scenarios of anti-reflective coatings increase, especially in the medical field, the porous surface of these coatings is prone to microbial growth and moisture contamination, which not only reduces the anti-reflective effect but also increases the risk of disease transmission. Therefore, the multifunctionality of anti-reflective coatings, including self-cleaning and antibacterial properties, is crucial for expanding their applications.

[0003] A promising strategy is to introduce titanium dioxide with antibacterial properties into antireflective coatings. Titanium dioxide has broad-spectrum antibacterial properties and is a typical photocatalytic antibacterial material. Under ultraviolet light irradiation, it generates highly oxidizing reactive oxygen species (ROS) that can damage bacterial cell walls, cell membranes, proteins, and enzyme systems, inhibiting spore / cell germination and reducing the likelihood of drug resistance.

[0004] The key to improving the antibacterial properties of coatings lies in increasing the contact area of ​​the antibacterial agent at the interface. The mixture of silica and titanium dioxide solves the defects of single titanium dioxide coatings, such as difficulty in film formation and easy particle aggregation. The inorganic network framework formed by silica increases the adhesion of the coating, inhibits the aggregation of titanium dioxide nanoparticles, and maintains a high specific surface area and high density of active sites. However, an excessively high proportion of titanium dioxide leads to a decrease in light transmittance. Therefore, it is necessary to optimize the ratio of silica to titanium dioxide to prepare a self-cleaning coating that combines anti-reflective and antibacterial properties. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a self-cleaning antibacterial and antireflective coating, and the coating itself. By mixing silica and titanium dioxide, a structure is generated with silica as the inorganic network framework and titanium dioxide attached, achieving antibacterial and self-cleaning properties while retaining antireflective performance. This solves the problems of easy contamination and bacterial growth in antireflective coatings. The self-cleaning antibacterial and antireflective coating comprises acid-catalyzed silica, alkali-catalyzed silica, and titanium dioxide. The high porosity and low refractive index of the silica coating give it excellent antireflective properties. The addition of titanium dioxide endows the coating with self-cleaning and antibacterial properties, making it less prone to contamination and capable of killing microorganisms on the surface.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution.

[0007] The first aspect of this invention provides a method for preparing a self-cleaning antibacterial and antireflective coating, comprising the following steps:

[0008] (1) Add silane to the solvent and stir, add acid catalyst solution and continue stirring and mixing, then age to obtain acid-catalyzed silica sol;

[0009] (2) Add silane to the solvent and stir, add alkaline catalyst solution and continue stirring and mixing, then age to obtain alkaline-catalyzed silica sol;

[0010] (3) Add titanate to solvent and stir, add concentrated hydrochloric acid and water and continue stirring and aging, then add solvent to dilute and obtain titanium dioxide sol;

[0011] (4) The acid-catalyzed silica sol obtained in step (1) is mixed and stirred with the titanium dioxide sol obtained in step (3) and then aged to obtain a mixed sol. Then it is mixed and stirred with the alkali-catalyzed silica sol obtained in step (2) and aged to obtain the final product.

[0012] Preferably, the silane in step (1) is selected from one or more of tetraethyl orthosilicate and ethyltriethoxysilane.

[0013] Preferably, the solvent in step (1) is selected from one or more of methanol, ethanol, propanol, n-butanol, pentanol, hexanol, heptanol, and octanol.

[0014] Preferably, the acid catalyst in step (1) is selected from one or more of concentrated hydrochloric acid, nitric acid, and acetic acid.

[0015] Preferably, the molar ratio of silane, solvent, and acid catalyst in step (1) is 1:10-150:0.5-5; more preferably, the molar ratio of silane, solvent, and acid catalyst is 1:20-80:0.6-0.8.

[0016] Preferably, in step (1), silane is added to the solvent and stirred for 10-30 min; acid catalyst solution is added and stirring is continued for 0.5-5 h; and the aging time is 7 days.

[0017] Preferably, the silane in step (2) is selected from one or more of tetraethyl orthosilicate and ethyltriethoxysilane.

[0018] Preferably, the solvent in step (2) is selected from one or more of methanol, ethanol, propanol, n-butanol, pentanol, hexanol, heptanol, and octanol.

[0019] Preferably, the alkaline catalyst in step (2) is selected from one or more of ammonia water and sodium hydroxide.

[0020] Preferably, the mass concentration of the ammonia water is 25-44 wt%.

[0021] Preferably, the molar ratio of silane, solvent, and alkaline catalyst in step (2) is 1:10-150:0.5-5; more preferably, the molar ratio of silane, solvent, and alkaline catalyst is 1:20-80:0.8-2.

[0022] Preferably, in step (2), silane is added to the solvent and stirred for 10-30 min; acid catalyst solution is added and stirring is continued for 0.5-5 h; and the aging time is 7 days.

[0023] Preferably, the titanate ester in step (3) is selected from one or more of tetrabutyl titanate and tetraisopropyl titanate.

[0024] Preferably, the solvent in step (3) is selected from one or more of methanol, ethanol, propanol, n-butanol, pentanol, hexanol, heptanol, and octanol.

[0025] Preferably, in step (3), the titanate is added to the solvent and stirred for 10-30 min; concentrated hydrochloric acid and water are added and stirring is continued for 0.5-10 h; the aging time is 3 days.

[0026] Preferably, the molar ratio of titanate, solvent, concentrated hydrochloric acid and water in step (3) is 1:60-150:0.5-2:1-10; more preferably, the molar ratio of titanate, solvent, concentrated hydrochloric acid and water is 1:80-130:0.6-1:3-6.

[0027] Preferably, the solvent used for dilution in step (3) is selected from one or more of methanol, ethanol, propanol, n-butanol, pentanol, hexanol, heptanol, and octanol, and is diluted to 1-10 times.

[0028] Preferably, in step (4), the molar ratio of the acid-catalyzed silica sol to the titanium dioxide sol is 1:0.8-1.2; and the molar ratio of the mixed sol to the alkali-catalyzed silica sol is 1:2-9.

[0029] Preferably, in step (4), the acid-catalyzed silica sol and titanium dioxide sol are mixed and stirred for 0.5-10 hours and then aged for 1 day to obtain a mixed sol; the mixed sol is then mixed and stirred with alkali-catalyzed silica sol for 0.5-10 hours and then aged for 1 day.

[0030] A second aspect of the present invention provides a self-cleaning antibacterial and antireflective coating prepared according to the above preparation method.

[0031] A third aspect of the present invention provides the application of the self-cleaning antibacterial and antireflective coating prepared according to the above preparation method in antireflective materials.

[0032] Preferably, the application involves applying the self-cleaning antibacterial and antireflective coating to the surface of a substrate, drying it at room temperature, and then calcining it at a high temperature to prepare an antireflective coating.

[0033] Preferably, the coating method is selected from any one of the following: dip coating, roller coating, and spin coating.

[0034] Preferably, the calcination temperature is 150-700℃ and the time is 0.1-3h; more preferably, the calcination temperature is 300-600℃ and the time is 0.5-2h.

[0035] Preferably, the thickness of the anti-reflective coating is 50-300 nm.

[0036] Compared with existing technologies, the present invention has the following advantages:

[0037] (1) The antireflective coating prepared by this invention has excellent antireflective properties, with an average transmittance greater than 95%. The high porosity and low refractive index of the silica coating enable it to have excellent antireflective properties. The silica forms a stable inorganic network framework, which reduces the agglomeration of titanium dioxide and lowers the overall refractive index, thus reducing the negative impact of titanium dioxide on antireflective properties.

[0038] (2) The coating has excellent antibacterial properties, and its antibacterial efficiency against various bacteria / fungi such as Escherichia coli and Staphylococcus aureus can reach 90%. The mixture of titanium dioxide and silicon dioxide increases the surface area of ​​titanium dioxide, thereby generating more ROS, which enhances the antibacterial properties of titanium dioxide. The generated inorganic network skeleton enhances the long-term effectiveness of the antibacterial ability of titanium dioxide.

[0039] (3) The coating has super-hydrophilic properties, which enables the coating to achieve a self-cleaning effect, reduce water vapor pollution, maintain the coating's excellent anti-reflective properties, and titanium dioxide has certain decomposition properties for organic matter, which can reduce organic matter pollution, enabling the coating to resist organic matter and water vapor, and enabling the coating to have anti-fog / fog properties to achieve a self-cleaning effect.

[0040] (4) The anti-reflective coating prepared by the present invention has super mechanical properties and can maintain self-cleaning, antibacterial and anti-reflective properties for a long time.

[0041] (5) The method for preparing the anti-reflective coating of the present invention has the advantages of simple process, low cost and good biocompatibility, and is suitable for large-scale promotion and use. Attached Figure Description

[0042] Figure 1 This is a SEM image of the self-cleaning antibacterial and antireflective coating prepared in Example 1 of the present invention.

[0043] Figure 2 This is a SEM image of the self-cleaning antibacterial and antireflective coating prepared in Example 5 of the present invention.

[0044] Figure 3 This is a SEM image of the self-cleaning antibacterial and antireflective coating prepared in Example 6 of the present invention.

[0045] Figure 4 The contact angle diagram is shown for the self-cleaning antibacterial and antireflective coating prepared in Example 1 of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0047] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention are commercially available or can be prepared by existing methods.

[0048] Example 1

[0049] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0050] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0051] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0052] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0053] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0054] SEM image of the self-cleaning antibacterial and antireflective coating prepared in Example 1 is shown below. Figure 1 As shown; from Figure 1 It can be seen that the titanium dioxide and acid-catalyzed silica in the coating encapsulate the alkali-catalyzed silica nanoparticles. A significant amount of titanium dioxide and acid-catalyzed silica forms large pores, and the nanoparticles have a particle size of approximately 20 nm. Hydrophobicity testing was performed, and the results are as follows... Figure 4 As shown in the figure. The results show the contact angle diagram of the self-cleaning antibacterial and antireflective coating prepared in Example 1; it can be seen from the figure that the contact angle of the coating is 3°, indicating superhydrophilicity.

[0055] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the mixed sol prepared above at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 2 hours.

[0056] Example 2

[0057] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0058] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:20:0.6:4.2.

[0059] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0060] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0061] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0062] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the mixed sol prepared above at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 2 hours.

[0063] Example 3

[0064] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0065] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0066] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:35:1.43.

[0067] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0068] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0069] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the mixed sol prepared above at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 2 hours.

[0070] Example 4

[0071] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0072] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0073] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min, add 28 wt% ammonia and continue stirring and mixing for 1 h, then age for 7 days to obtain alkali-catalyzed silica sol; wherein the molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0074] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:80:0.75:4.

[0075] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0076] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the mixed sol prepared above at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 2 hours.

[0077] Example 5

[0078] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0079] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0080] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0081] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0082] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 2:8 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0083] The SEM image of the self-cleaning antibacterial and antireflective coating prepared in Example 5 is shown below. Figure 2 As shown; from Figure 1 It can be seen that by reducing the use of titanium dioxide and acid-catalyzed silicon dioxide, the porosity of the coating disappears, the distribution becomes more uniform, and the particle size is still around 20nm.

[0084] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the mixed sol prepared above at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 2 hours.

[0085] Example 6

[0086] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0087] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0088] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0089] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0090] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 1:9 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0091] SEM image of the self-cleaning antibacterial and antireflective coating obtained in Example 6 is shown below. Figure 3 As shown; from Figure 1 It can be seen that by continuing to reduce the use of titanium dioxide and acid-catalyzed silicon dioxide, the coating exhibits a uniform distribution of nanoparticles with a small number of pores, and the particle size is still around 20nm.

[0092] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the mixed sol prepared above at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 2 hours.

[0093] Example 7

[0094] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0095] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0096] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0097] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0098] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0099] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the mixed sol prepared above at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 300°C for 2 hours.

[0100] Example 8

[0101] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0102] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0103] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0104] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0105] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0106] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the mixed sol prepared above at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 400℃ for 2 hours.

[0107] Example 9

[0108] A self-cleaning, antibacterial, and antireflective coating is prepared by means of the following steps:

[0109] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0110] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0111] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0112] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0113] Furthermore, the self-cleaning antibacterial and antireflective coating prepared above is used to prepare an antireflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the final mixed sol prepared above at a constant rate and left to stand for 1 minute. Then it is pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 1 hour.

[0114] Comparative Example 1

[0115] A coating, the preparation method of which specifically includes the following steps:

[0116] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0117] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0118] (3) The acid-catalyzed silica sol obtained in step (1) and the alkali-catalyzed silica sol obtained in step (2) are mixed and stirred for 1 hour at a molar ratio of 3:7 and aged for 1 day to obtain the final product.

[0119] Further, the coating prepared above is used to prepare an anti-reflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the final mixed sol prepared above at a constant rate and left to stand for 1 minute. Then it is pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 300°C for 2 hours.

[0120] Comparative Example 2

[0121] A coating, the preparation method of which specifically includes the following steps:

[0122] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0123] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0124] (3) The acid-catalyzed silica sol obtained in step (1) and the alkali-catalyzed silica sol obtained in step (2) are mixed and stirred for 1 hour and aged for 1 day at a molar ratio of 2:8 to obtain the final product.

[0125] Further, the coating prepared above is used to prepare an anti-reflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the final mixed sol prepared above at a constant rate and left to stand for 1 minute. Then it is pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 300°C for 2 hours.

[0126] Comparative Example 3

[0127] A coating, the preparation method of which specifically includes the following steps:

[0128] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0129] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0130] (3) The acid-catalyzed silica sol obtained in step (1) and the alkali-catalyzed silica sol obtained in step (2) are mixed and stirred for 1 hour and aged for 1 day to obtain the final product.

[0131] Further, the coating obtained above is used to prepare an anti-reflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the final mixed sol at a constant rate and left to stand for 1 minute, then pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 300°C for 1 hour.

[0132] Comparative Example 4

[0133] A coating, the preparation method of which specifically includes the following steps:

[0134] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0135] (2) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0136] (3) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 7:3 and stirred for 1 hour, and then aged for 1 day to obtain the final product.

[0137] Further, the coating prepared above is used to prepare an anti-reflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the final mixed sol prepared above at a constant rate and left to stand for 1 minute. Then it is pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 1 hour.

[0138] Comparative Example 5

[0139] A coating, the preparation method of which specifically includes the following steps:

[0140] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0141] (2) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0142] (3) The alkaline-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 7:3 and stirred for 1 hour, and then aged for 1 day to obtain the product.

[0143] Further, the coating prepared above is used to prepare an anti-reflective glass plate. The specific steps are as follows: the completely clean glass plate is immersed in the final mixed sol prepared above at a constant rate and left to stand for 1 minute. Then it is pulled up at a uniform speed, dried at room temperature for 15 minutes, and finally sintered at 550°C for 1 hour.

[0144] Comparative Example 6

[0145] A coating, the preparation method of which specifically includes the following steps:

[0146] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0147] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0148] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0149] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0150] Furthermore, the coating obtained above is used to prepare an anti-reflective glass plate. The specific steps are as follows: after dipping a mixed brush into the sol, it is uniformly rolled onto the surface of a completely clean glass plate, dried at room temperature for 15 minutes, and finally sintered at 550℃ for 1 hour.

[0151] Comparative Example 7

[0152] A coating, the preparation method of which specifically includes the following steps:

[0153] (1) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add concentrated hydrochloric acid and water and continue stirring and mixing for 1 h. Then age for 7 days to obtain acid-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol, concentrated hydrochloric acid and water is 1:32:0.6:4.2.

[0154] (2) Add tetraethyl orthosilicate to ethanol and stir for 15 min. Add 28 wt% ammonia and continue stirring and mixing for 1 h. Then age for 7 days to obtain alkali-catalyzed silica sol. The molar ratio of tetraethyl orthosilicate, ethanol and 25-28 wt% ammonia is 1:45.22:1.43.

[0155] (3) Add tetrabutyl titanate to ethanol and stir for 1 hour. Add concentrated hydrochloric acid and water and continue stirring for 4 hours. Then age for 3 days. Then add ethanol to dilute at a ratio of 1:5 to obtain titanium dioxide sol. The molar ratio of tetrabutyl titanate, ethanol, concentrated hydrochloric acid and water is 1:125:0.75:4.

[0156] (4) The acid-catalyzed silica sol obtained in step (1) and the titanium dioxide sol obtained in step (3) are mixed at a molar ratio of 1:1 and stirred for 1 hour, and then aged for 1 day to obtain a mixed sol. Then the mixed sol and the alkali-catalyzed silica sol obtained in step (2) are mixed at a molar ratio of 3:7 and stirred for 1 hour and aged for 1 day to obtain the final product.

[0157] Furthermore, the coating obtained above is used to prepare an anti-reflective glass plate. The specific steps are as follows: place a completely clean glass plate on a spin coater, drop the sol onto the glass plate, rotate to dry, and finally sinter at 550℃ for 2 hours.

[0158] Verification Example 1

[0159] The coatings prepared in Examples 1-9 and Comparative Examples 1-7 were tested for light transmittance and antibacterial properties. The results showed that the coating in Example 1 had an average light transmittance greater than 95.5% and an antibacterial rate of over 90% against *Escherichia coli* and *Staphylococcus aureus*. The coatings in Examples 2-4 had an average light transmittance greater than 93% and an antibacterial rate of over 90% against *Escherichia coli* and *Staphylococcus aureus*. The coating in Example 5 had an average light transmittance greater than 96.5% and an antibacterial rate of over 70% against *Escherichia coli* and *Staphylococcus aureus*. The coating in Example 6 had an average light transmittance greater than 97% and an antibacterial rate of over 50% against *Escherichia coli* and *Staphylococcus aureus*. The coatings in Examples 7-8 had an average light transmittance greater than 95.5% and an antibacterial rate of over 40% against *Escherichia coli* and *Staphylococcus aureus*. The coating in Example 9 had an average light transmittance greater than 95.5% and an antibacterial rate of over 70% against *Escherichia coli* and *Staphylococcus aureus*. Comparative Examples 1-3: The average transmittance of the coating is greater than 95%, with no antibacterial properties. Comparative Example 4: The average transmittance of the coating is greater than 92%, with an antibacterial rate of 50% against *Escherichia coli* and *Staphylococcus aureus*. Comparative Example 5: The average transmittance of the coating is greater than 94%, with an antibacterial rate of over 90% against *Escherichia coli* and *Staphylococcus aureus*. Comparative Example 6: The average transmittance of the coating is greater than 81%, with an antibacterial rate of over 50% against *Escherichia coli* and *Staphylococcus aureus*. Comparative Example 7: The average transmittance of the coating is greater than 94%, with an antibacterial rate of over 80% against *Escherichia coli* and *Staphylococcus aureus*.

[0160] The coatings prepared according to the methods of Comparative Examples 1-3 did not contain titanium dioxide. Since silica alone does not have antibacterial properties, the coatings of Comparative Examples 1-3 had no antibacterial properties. Alkali-catalyzed silica provided the coating's antireflective properties; in Comparative Example 4, the reduced use of alkali-catalyzed silica significantly reduced the average transmittance. In Comparative Example 5, the use of acid-catalyzed silica was reduced. Because the antireflective properties of acid-catalyzed silica were still superior to those of titanium dioxide, and the film-forming properties of the coating were worse, the average transmittance decreased, while the use of titanium dioxide maintained high antibacterial properties. Comparative Examples 6 and 7 used roller coating and spin coating methods, respectively, resulting in poorer coating surfaces and significantly reduced control over film thickness, thus reducing both transmittance and antibacterial properties.

[0161] A single silica coating is porous and easily contaminated by moisture, leading to reduced transmittance. It is also susceptible to contamination by organic matter and microorganisms. A single titanium dioxide coating has antibacterial effects, but it reduces transmittance compared to the original glass, and its film-forming properties are poor. The combination of silica and titanium dioxide integrates the excellent properties of both, achieving a multi-functionality of self-cleaning, antibacterial, and anti-reflective properties, while overcoming the drawbacks of titanium dioxide such as easy agglomeration and excessively rapid release of antibacterial properties. The silica-titanium dioxide composite coating significantly reduces light reflection and scattering caused by pure titanium dioxide by regulating the overall refractive index, inhibiting titanium dioxide particle agglomeration and grain coarsening, and improving film density and surface smoothness. This weakens the negative impact of titanium dioxide on transmittance and endows the coating with anti-reflective and high-transparency properties.

[0162] The above detailed embodiments provide a specific description of the technical solutions involved in this invention. It should be noted that the above description is only intended to help those skilled in the art better understand the methods and ideas of this invention, and is not intended to limit the scope of the invention. Without departing from the principles of this invention, those skilled in the art can make appropriate adjustments or modifications to this invention, and such adjustments and modifications should also fall within the protection scope of this invention.

Claims

1. A method for preparing a self-cleaning antibacterial and antireflective coating, characterized in that, Includes the following steps: (1) Add silane to the solvent and stir, add acid catalyst solution and continue stirring and mixing, then age to obtain acid-catalyzed silica sol; (2) Add silane to the solvent and stir, add alkaline catalyst solution and continue stirring and mixing, then age to obtain alkaline-catalyzed silica sol; (3) Add titanate to solvent and stir, add concentrated hydrochloric acid and water and continue stirring and aging, then add solvent to dilute and obtain titanium dioxide sol; (4) The acid-catalyzed silica sol obtained in step (1) is mixed and stirred with the titanium dioxide sol obtained in step (3) and then aged to obtain a mixed sol. Then it is mixed and stirred with the alkali-catalyzed silica sol obtained in step (2) and aged to obtain the final product.

2. The preparation method according to claim 1, characterized in that, The silanes mentioned in steps (1) and (2) are selected from one or more of tetraethyl orthosilicate and ethyltriethoxysilane.

3. The preparation method according to claim 1, characterized in that, The solvents mentioned in steps (1) and (2) are selected from one or more of methanol, ethanol, propanol, n-butanol, pentanol, hexanol, heptanol, and octanol.

4. The preparation method according to claim 1, characterized in that, The acid catalyst mentioned in step (1) is selected from one or more of concentrated hydrochloric acid, nitric acid, and acetic acid.

5. The preparation method according to claim 1, characterized in that, The alkaline catalyst mentioned in step (2) is selected from one or more of ammonia water and sodium hydroxide.

6. The preparation method according to claim 1, characterized in that, The titanate ester mentioned in step (3) is selected from one or more of tetrabutyl titanate and tetraisopropyl titanate.

7. The preparation method according to claim 1, characterized in that, In step (4), the molar ratio of acid-catalyzed silica sol to titanium dioxide sol is 1:0.8-1.2; the molar ratio of mixed sol to alkali-catalyzed silica sol is 1:2-9.

8. The preparation method according to claim 1, characterized in that, In step (4), the acid-catalyzed silica sol and titanium dioxide sol are mixed and stirred for 0.5-10 hours and then aged for 1 day to obtain a mixed sol; the mixed sol is mixed and stirred with the alkali-catalyzed silica sol for 0.5-10 hours and then aged for 1 day.

9. The self-cleaning antibacterial and antireflective coating prepared by the preparation method according to any one of claims 1-8.

10. The application of the self-cleaning antibacterial and antireflective coating prepared by the preparation method according to any one of claims 1-8 in antireflective materials.

Images