A method for preparing a self-repairable highly hydrophobic and highly transparent organic glass film layer

Abstract

The present invention belongs to the technical field of nanomaterial preparation, and discloses a method for preparing a self-repairing highly hydrophobic and highly transparent organic glass film layer. The method comprises: the first step of treating the organic glass surface with polysiloxane and solidifying it into a film; the second step of grinding and dispersing the nano-diamond prepared by the detonation method, oxidizing and removing impurities, extracting nano-diamond particles of a certain particle size by high-speed centrifugation, and dispersing them together with Ag@TiO2 nano-particles prepared by the hydrothermal method in an ethanol solution of water and polyvinyl pyrrolidone to form a PVP dispersion of the two, and then spraying them on the organic glass surface, drying and solidifying them into a film. The film layer prepared by the present invention has good hydrophobicity and high light transmittance, and can self-repair under light. The production method has simple steps, low energy consumption, is suitable for industrial production, and has strong practicality.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano film material preparation, and relates to a method for preparing a self-repairable highly hydrophobic and highly light-transmitting organic glass film layer, which is used in the fields of aerospace glass, rail transit glass, automotive glass, architectural glass, electronic product screens, etc. Background Art

[0002] With the development of science and technology, the scope of human exploration of the world is increasing, the pace of life is getting faster and faster, and spacecraft, deep-sea probes, high-speed trains, cars, electronic products, buildings, etc. are becoming more and more high-tech and intelligent. Organic glass has a large application range in these military and civilian fields due to its advantages such as high strength and light weight. These application fields have high requirements for the strength performance and light transmittance of organic glass devices. However, organic glass is easy to absorb water. When it is corroded by moisture in the air, it is easy to age and cause the strength performance to decrease. It has safety risks when used in aerospace and rail transportation. Therefore, improving the hydrophobicity of the surface of organic glass devices and making them have self-repairing functions will be very helpful to extend their service life.

[0003] In response to the above problems, the method of improving the organic glass formula or preparing a hydrophobic film layer on the organic glass surface is generally used to solve them. For example, the patent application "A high-transmittance anti-fog organic glass and its preparation method" (publication number: CN108659437A, announcement date October 16, 2018) optimizes the sorbitol, nano-vanadium dioxide powder, dispersant and polymethyl methacrylate in the organic glass formula, so that the organic glass transmittance is increased by 10-15%, but it is easy to cause the strength performance of the organic glass to decrease. For example, the patent application "Anti-reflection film" (publication number: CN115185021A, publication date: October 14, 2022) discloses a method for preparing an anti-reflection film that simultaneously achieves high anti-reflection and high scratch resistance. It uses hollow silica nanoparticles to reduce the reflection of light, and uses nano-diamond particles modified by silane coupling agents to achieve high scratch resistance and high transparency. Another example is the patent application "A method for preparing high-transmittance super-hydrophobic glass" (publication number: CN114620955A, publication date: June 14, 2022), which discloses a method for preparing high-transmittance super-hydrophobic glass. It uses inorganic glass as the supporting skeleton. During the molding process of the organic glass coating, a long-chain macromolecular layer is grafted on its surface, and extends into the organic glass layer to participate in polymerization molding, and then an organic hydrophobic layer is coated on the organic glass layer.

[0004] The present invention develops a method for preparing a self-repairable high-transmittance, high-hydrophobicity and high-transmittance organic glass film layer that can be applied to the surface of organic glass, can avoid the corrosion of the organic glass substrate by external water vapor, and has good light transmittance. Summary of the invention

[0005] The purpose of the present invention is to improve the corrosion resistance of the organic glass substrate to external water vapor to extend its service life. The specific method is to prepare a layer of low surface energy organic macromolecular film layer with high hydrophobicity and adhesion on the surface of the organic glass device without changing the organic glass substrate, and compositely deposit functional nano diamond particles and Ag@TiO2 particles on the film layer to form a rough microstructure required for the hydrophobic structure. The organic glass device finally obtained has good light transmittance and can be self-repaired under light. The present invention has a simple process flow, low energy consumption, easy-to-obtain raw materials, low cost, simple operation, and is suitable for industrial production and practical application.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a self-repairable highly hydrophobic and highly transparent organic glass film layer comprises the following steps:

[0008] Step (1), preparation of nano diamond powder: weigh detonation diamond powder and NaCl powder, place them in an agate ball mill, take out the ball-milled powder and place it in a beaker, add deionized water and concentrated nitric acid, stir and oxidize on a magnetic stirrer, then take out and centrifuge in a high-speed centrifuge for cleaning, and then take out the cleaned diamond powder for use.

[0009] The ratio of the detonation diamond powder, NaCl powder, deionized water and concentrated nitric acid is 1g:20g:400mL:50mL; the particle size of the detonation diamond powder is below 100nm, the ball milling speed is 350r / min, the time is 3h, the concentration of concentrated nitric acid is 65vol%, the stirring oxidation time on the magnetic stirrer is 3h; the centrifugal speed of the high-speed centrifuge is 7000r / min, and the centrifugal washing is performed 3 times.

[0010] Step (2), preparation of Ag@TiO2 sol: add glacial acetic acid to ethanol and mix well, add tetrabutyl titanate and then acetylacetone, stir to react; then add a mixed solution of water and ethanol dropwise at constant pressure to finally obtain a light yellow transparent sol; add polyethylene glycol to the above light yellow transparent sol, react under reflux in a water bath to obtain a modified TiO2 sol; add the modified TiO2 sol to an AgNO3 aqueous solution, then add ethylene glycol, stir magnetically and then heat to react, cool to room temperature to obtain an Ag@TiO2 sol.

[0011] The ratio of glacial acetic acid, ethanol, tetrabutyl titanate, acetylacetone, water and ethanol mixture and polyethylene glycol is 2.9mL:69mL:17.08mL:0.5mL:11mL:2g, and the stirring reaction time is 1h; in the water and ethanol mixture, the volume ratio of water to ethanol is 1:10, and the constant pressure drop time is 60min; the molecular weight of polyethylene glycol is 2000, the water bath temperature is 80°C, and the reaction time is 1h; the volume ratio of tetrabutyl titanate, AgNO3 aqueous solution and ethylene glycol is 17.08:1:30, the concentration of AgNO3 aqueous solution is 0.05mol / L, magnetic stirring is carried out for 30 minutes, and the temperature is raised to 100°C for reaction for 3h.

[0012] Step (3), taking the above-mentioned nano-diamond powder and the above-mentioned Ag@TiO2 sol, adding them to an ethanol solution of polyvinyl pyrrolidone (PVP), and then ultrasonically dispersing them evenly to form a PVP dispersion of nano-diamond and Ag@TiO2, thereby completing the preparation of the spray solution.

[0013] The ratio of the nano-diamond powder, Ag@TiO2 sol and PVP ethanol solution is 15g:10mL:1000mL, wherein the concentration of the PVP ethanol solution is 20vol%.

[0014] Step (4), cleaning the plexiglass.

[0015] Step (5), coating the polysiloxane on the surface of the organic glass, drying and curing to form a film with a thickness of 30 to 100 μm.

[0016] Step (6), placing the organic glass with a polysiloxane coating after drying in step (5) on a hot plate, and using an ultrasonic sprayer to evenly spray the spray solution prepared in step (3) onto the surface of the organic glass. The direction of the nozzle and the distance to the organic glass are adjustable. The nozzle is controlled to spray vertically onto the glass surface, and the distance to the organic glass is adjustable and controlled within 10 to 30 cm. During the spraying process, the temperature of the hot plate below the organic glass is controlled within 200° C. to 280° C. Finally, the sprayed nano-diamond and Ag@TiO2 are cured into a film in a single particle distribution state through thermal drying, and finally a self-repairable high-transmittance and high-hydrophobic organic glass film layer is obtained.

[0017] The beneficial effects of the present invention are:

[0018] (1) In the present invention, polysiloxane is coated on the surface of organic glass. The silane functional group can react with the glass surface through hydroxylation to generate a strong bonding force. The alkane group is hydrophobic. The hydrophobic film layer finally formed also has the characteristic of low surface energy.

[0019] (2) The present invention prepares nano-diamond powder by detonation method, ball milling, strong acid oxidation, high-speed centrifugal purification, and then dispersed in PVP ethanol solution together with Ag@TiO2 sol to prepare dispersion, and then ultrasonically sprayed on the surface of organic glass, and then thermally cured to form nano-diamond and nano-Ag@TiO2 particle films. The particle film layer provides the nano-rough surface required for the super-hydrophobic structure, and Ag@TiO2 can use visible light to effectively photocatalytically degrade pollutants. When the hydrophobic film layer is damaged, the Ag@TiO2 nanoparticles can timely degrade the scratched surface pollutants under light, and the alkane groups of the polysiloxane coating automatically migrate to the surface of the film layer under the action of light and heat, and finally the damaged film layer can achieve self-repair.

[0020] (3) PVP has the function of dispersing and fixing nanoparticles. Nanodiamond particles and nanoAg@TiO2 particles are fixed on the film layer with its help.

[0021] (4) The nano-diamond particles in the film layer prepared by the present invention have the effect of increasing light transmittance and hydrophobicity; the Ag@TiO2 nano-particles can not only achieve self-cleaning, but also have a certain antibacterial effect.

[0022] (5) The operating conditions of the present invention are easy to control, the process flow is simple, environmentally friendly and has low energy consumption. The solvents used in the spraying process, such as ethanol, can be completely evaporated and leave the surface of the glass device, and can be recovered and reused after condensation. There is no need to further remove impurities from the thin layer. The prepared film layer has high purity, uniform distribution, and is easy to industrialize.

[0023] Table 1 is the hydrophobicity, light transmittance and strength performance data of the blank organic glass substrate, Example 1 and Example 2. It can be seen that the water drop contact angle has been significantly improved, and the light transmittance has also been improved by 4-5%. The water drop contact angle of Example 2 is slightly lower than that of Example 1, which may be because the hydrophobic film layer of Example 2 is thinner than that of Example 1. The light transmittance of both embodiments has been significantly improved, thanks to the high light transmittance of nanodiamonds. The four-point bending strength data show that the implementation of the present invention will not cause a decrease in the basic strength performance of the organic glass substrate. In order to examine the self-repairing ability of the film layer, the present invention uses a Vickers hardness tester to artificially create defects in the hydrophobic layer with a load of 10kg, and then exposes the defect to a xenon lamp (power 250w, simulated sunlight) for 12 hours, 24 hours, and 48 hours. After that, the water drop contact angle at the defect is examined. As shown in Table 2, it can be seen that with the increase of the illumination time, the water drop contact angle is increasing, indicating that the hydrophobic function of the film layer is gradually self-repairing. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific implementation examples so that those skilled in the art can better understand the present invention, but the present invention is not limited to the following embodiments.

[0025] Example 1

[0026] Weigh 1g of detonated diamond powder with a particle size of less than 100nm and 20g of NaCl powder, place them in an agate ball mill, and mill them at a speed of 350r / min for 3h. Take out the ball-milled powder and place it in a beaker, add 400mL of deionized water and 50mL of 65% concentrated nitric acid, stir and oxidize it on a magnetic stirrer for 3h, then centrifuge and wash it in a centrifuge at a speed of 7000r / min for 3 times, and then take out the cleaned diamond powder for use.

[0027] Add 2.9mL of glacial acetic acid to 69mL of ethanol, stir to mix the two evenly, then add 17.08mL of tetrabutyl titanate, then add 0.5mL of acetylacetone, continue stirring to react for 1h, then use a constant pressure funnel to slowly drop the mixture formed by 1mL of water and 10mL of ethanol into the above reaction system, drip it all out in 60min, and then obtain a light yellow transparent sol. Then add 2g of polyethylene glycol (PEG, Mw=2000) to the above light yellow transparent sol, reflux in a water bath at 80℃ for 1h to obtain a modified TiO2 sol for standby use. Slowly add the above TiO2 sol to 1mL of 0.05mol / L AgNO3 aqueous solution, then add 30mL of ethylene glycol, stir magnetically for 30min, then heat to 100℃ for 3h and naturally cool to room temperature.

[0028] Take 15g of the above-mentioned reserved nano-diamond powder and 10mL of the above-mentioned Ag@TiO2 sol, add them into 1000mL of 20vol% polyvinyl pyrrolidone (PVP) ethanol solution, and then ultrasonically disperse them evenly to form a PVP dispersion of nano-diamond and Ag@TiO2, completing the preparation of the spray solution.

[0029] The organic glass was cleaned and dried, and a diluted solution of perfluorodecyl triethoxysilane in anhydrous ethanol (mass percentage concentration 1%) was applied to the surface of the organic glass. After drying at 230°C, a hydrophobic film layer of about 50 μm thick was obtained. The coated organic glass was placed on a hot plate, and the above-mentioned nanodiamond and Ag@TiO2 PVP dispersion was sprayed onto the organic glass surface using an ultrasonic sprayer. The spraying amount was controlled at 50 mL / m 2 The direction of the nozzle and the distance to the organic glass were 20 cm. The nozzle was controlled to spray vertically onto the glass surface. During the spraying process, the temperature of the hot plate under the organic glass was controlled at 250°C. Finally, the sprayed nano-diamond and Ag@TiO2 were dried and solidified to form a film.

[0030] Example 2

[0031] Weigh 1g of detonated diamond powder with a particle size of less than 50nm and 20g of NaCl powder, place them in an agate ball mill, and mill them at a speed of 350r / min for 3h. Take out the ball-milled powder and place it in a beaker, add 400mL of deionized water and 50mL of 65% concentrated nitric acid, stir and oxidize it on a magnetic stirrer for 3h, then centrifuge and wash it in a centrifuge at a speed of 7000r / min for 3 times, and then take out the cleaned diamond powder for use.

[0032] Add 2.9mL of glacial acetic acid to 69mL of ethanol, stir to mix the two evenly, then slowly add 17.08mL of tetrabutyl titanate, then add 0.5mL of acetylacetone, continue stirring to react for 1h, then use a constant pressure funnel to slowly drop the mixture formed by 1mL of water and 10mL of ethanol into the above reaction system, drip it all out in 60min, and then obtain a light yellow transparent sol. Then add 2g of polyethylene glycol (PEG, Mw=2000) to the above sol, reflux in a water bath at 80℃ for 1h to obtain a modified TiO2 sol for standby use. Slowly add the above TiO2 sol to 1mL of 0.05mol / L AgNO3 aqueous solution, then add 30mL of ethylene glycol, stir magnetically for 30min, then heat to 100℃ for 3h and naturally cool to room temperature.

[0033] Take 15g of the above-mentioned reserved nano-diamond powder and 10mL of the above-mentioned Ag@TiO2 sol, add 1000mL of 20vol% polyvinyl pyrrolidone (PVP) ethanol solution, and then ultrasonically disperse them evenly to form a PVP dispersion of nano-diamond and Ag@TiO2, completing the preparation of the spray solution.

[0034] The organic glass was cleaned and dried, and a diluted solution of perfluorooctyl triethoxysilane in anhydrous ethanol (mass percentage concentration 1%) was applied to the surface of the organic glass. After drying at 220°C, a hydrophobic film layer of about 30 μm thick was obtained. The coated organic glass was placed on a hot plate, and an ultrasonic sprayer was used to spray the above-mentioned nanodiamond and Ag@TiO2 PVP dispersion onto the organic glass surface. The direction of the nozzle and the distance to the organic glass were 20 cm. The nozzle was controlled to spray vertically onto the glass surface. During the spraying process, the temperature of the hot plate under the organic glass was controlled at 250°C. Finally, the sprayed nanodiamond and Ag@TiO2 were dried and solidified to form a film. The spraying amount was controlled at 50 mL / m 2 .

[0035] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

[0036] Table 1

[0037] No coating Example 1 Example 2 Total light transmittance (%) 94.1 99.1 98.9 Water drop contact angle (°) 60.2 160.1 154.8 Four-point bending strength 425MPa 430MPa 426MPa

[0038] Table 2 Effect of illumination time on contact angle of water droplets at defects

[0039]

Claims

1. A method for preparing a self-repairable highly hydrophobic and highly transparent organic glass film layer, characterized in that: The steps include: Step (1), preparation of nano diamond powder: weigh detonation diamond powder and NaCl powder, place them in an agate ball mill, take out the milled powder and place it in a beaker, add deionized water and concentrated nitric acid, stir and oxidize on a magnetic stirrer, then take out and centrifuge in a high-speed centrifuge for cleaning, and then take out the cleaned diamond powder for use; Step (2), preparation of Ag@TiO2 sol: add glacial acetic acid to ethanol and mix well, add tetrabutyl titanate and then acetylacetone, stir to react; then drip a mixed solution of water and ethanol at constant pressure to finally obtain a light yellow transparent sol; add polyethylene glycol to the above light yellow transparent sol, react under reflux in a water bath to obtain a modified TiO2 sol; add the modified TiO2 sol to an AgNO3 aqueous solution, then add ethylene glycol, stir magnetically and heat to react, cool to room temperature to obtain an Ag@TiO2 sol; the ratio of glacial acetic acid, ethanol, tetrabutyl titanate, acetylacetone, a mixed solution of water and ethanol and polyethylene glycol is 2.9 mL: 69 mL: 17.08 mL: 0.5 mL: 11 mL: 2 g, and the stirring reaction time is 1 h; in the mixed solution of water and ethanol, the volume ratio of water to ethanol is 1:10, and the constant pressure dripping time is 60 min; the molecular weight of polyethylene glycol is 2000, the water bath temperature is 80 ℃, and the reaction time is 1 h; the volume ratio of tetrabutyl titanate, AgNO3 aqueous solution and ethylene glycol is 17.08:1:30, the concentration of AgNO3 aqueous solution is 0.05 mol / L, magnetic stirring is performed for 30 minutes, and the temperature is raised to 100 ℃ for reaction for 3 hours; Step (3), taking the above-mentioned nano-diamond powder and the above-mentioned Ag@TiO2 sol, adding them to an ethanol solution of polyvinyl pyrrolidone, and then uniformly dispersing them by ultrasonication to form a polyvinyl pyrrolidone dispersion of nano-diamond and Ag@TiO2, thereby completing the preparation of the spray solution; Step (4), cleaning the plexiglass; Step (5), coating the polysiloxane on the surface of the organic glass, drying and curing to form a film; Step (6), placing the organic glass with the polysiloxane coating after drying in step (5) on a hot plate, and using an ultrasonic sprayer to evenly spray the spray solution prepared in step (3) onto the surface of the organic glass. The direction of the nozzle and the distance to the organic glass are adjustable. The nozzle is controlled to spray vertically onto the glass surface, and the distance to the organic glass is adjustable and controlled within 10-30 cm. During the spraying process, the temperature of the hot plate below the organic glass is controlled within 200° C.-280° C. Finally, the sprayed nano-diamond and Ag@TiO2 are cured into a film in a single particle distribution state after thermal drying, and finally a self-repairable high-transmittance and high-hydrophobic organic glass film layer is obtained.

2. The method for preparing a self-repairable highly hydrophobic and highly transparent organic glass film layer according to claim 1, characterized in that: In step (1), the ratio of the detonation diamond powder, NaCl powder, deionized water and concentrated nitric acid is 1 g:20 g:400 mL:50 mL; the particle size of the detonation diamond powder is below 100 nm, the ball milling speed is 350 r / min, the time is 3 h, the concentration of concentrated nitric acid is 65 vol%, the stirring oxidation time on the magnetic stirrer is 3 h; the high-speed centrifuge speed is 7000 r / min, and the centrifugal washing is performed 3 times.

3. The method for preparing a self-repairable highly hydrophobic and highly transparent organic glass film layer according to claim 1, characterized in that: In step (3), the ratio of the nano-diamond powder, Ag@TiO2 sol and PVP ethanol solution is 15 g:10 mL:1000 mL, wherein the concentration of the PVP ethanol solution is 20 vol%.

4. The method for preparing a self-repairable highly hydrophobic and highly transparent organic glass film layer according to claim 1, characterized in that: In step (5), the film thickness is 30 to 100 microns.

5. The method for preparing a self-repairable highly hydrophobic and highly transparent organic glass film layer according to claim 1, characterized in that: In step (6), the distance from the nozzle to the plexiglass is adjustable and controlled within a range of 10 to 30 cm.

Images