A CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, its preparation method and application

Abstract

The application provides a CeO2-PDA / Al2O3@polyurethane super-hydrophobic coating and a preparation method and application thereof, and belongs to the technical field of super-hydrophobic material preparation; in the application, dopamine is used to modify nanoparticles CeO2, so that the dispersibility and stability of the nanoparticles CeO2 in a polyurethane main coating are improved; then, silane coupling agent KH560, fluorosilane modifier and nanoparticles Al2O3 are added to be mixed, so that the CeO2-PDA / Al2O3@polyurethane super-hydrophobic coating (PDA is polydopamine) is obtained; the CeO2-PDA / Al2O3@polyurethane super-hydrophobic coating has the outstanding advantages of warm greenhouse spraying curing, high surface stability, difficulty in agglomeration of surface micro-nanoparticles, long aging property and good weather resistance; the super-hydrophobic coating can be prepared at room temperature, has a better application prospect in super-hydrophobic treatment of object surfaces, and has strong practical functions and industrial popularization value.

Description

Technical Field

[0001] This invention belongs to the field of superhydrophobic material preparation technology, specifically relating to a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, its preparation method, and its application. Background Technology

[0002] The development of superhydrophobic materials is closely related to the discovery of the lotus effect—water droplets can roll freely on the surface of a lotus leaf, carrying away dust and thus earning the reputation of "rising from the mud unsullied, and standing tall and pure without being seductive." Numerous in-depth studies of lotus leaves have shown that this effect is closely related to the rough structure of its surface. The rough structure of a lotus leaf is, to some extent, similar to micro- and nano-sized "peaks" and "valleys." These micro- and nano-sized "peaks" effectively isolate water droplets from contacting the "valleys," creating an air barrier between the droplet and the leaf surface, thereby repelling contact. In this way, water droplets can roll freely on the lotus leaf surface, carrying away dust and creating the lotus effect. It is known that the contact angle of a water droplet on a lotus leaf surface can reach over 150°, and that the droplet can roll freely on the surface. Therefore, superhydrophobicity is generally defined as a contact angle with a water droplet greater than 150° and a roll-off angle less than 10°. Besides lotus leaves, other natural biological tissues with superhydrophobic properties include rose petals, butterfly wings, water strider legs, mosquito compound eyes, and various plant leaves. Therefore, superhydrophobic materials can be prepared by mimicking the lotus leaf effect.

[0003] Superhydrophobic materials possess excellent properties and can be used for metal corrosion protection, anti-icing and anti-fogging, and rain and water repellency. In recent years, superhydrophobic materials have also been applied to household appliances, oil pipelines, desert water collection, and ship buoyancy enhancement, demonstrating unparalleled advantages in these applications. However, existing preparation techniques and methods for superhydrophobic materials generally suffer from drawbacks during application, including ineffective curing under greenhouse conditions, easy aggregation of surface micro- and nano-particles, poor surface stability, short efficiency, and poor weather resistance. Furthermore, they often completely lose their superhydrophobic properties after a certain period of use. These shortcomings significantly limit the practical application of superhydrophobic coatings, making them mostly suitable only for indoor use and small objects, lacking industrial-scale commercialization value.

[0004] Therefore, there is a need to develop a more universal superhydrophobic coating preparation technology that can be prepared by simple spraying and has high surface stability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, its preparation method, and its applications. This invention modifies CeO2 nanoparticles with dopamine to improve their dispersibility and stability within the polyurethane substrate coating. Subsequently, a silane coupling agent KH560, a fluorosilane modifier, and Al2O3 nanoparticles are added and mixed to obtain the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating (PDA is polydopamine). The CeO2-PDA / Al2O3@polyurethane superhydrophobic coating exhibits significant advantages, including room temperature spray curing, high surface stability, minimal agglomeration of surface micro / nano particles, long service life, and good weather resistance. The superhydrophobic coating can be prepared at room temperature and has promising applications in superhydrophobic treatment of object surfaces, possessing strong practical functionality and industrial promotion value.

[0006] To achieve the above-mentioned technical objectives, the present invention employs the following technical means:

[0007] This invention first provides a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, wherein the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating has a lotus leaf-like rough surface; the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating is based on polyurethane, and CeO2-PDA and hydrophobically modified Al2O3 nanoparticles are dispersed on the main coating; the CeO2-PDA is polydopamine (PDA) coated on the CeO2 surface.

[0008] This invention also provides a method for preparing the above-mentioned CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, specifically including the following steps:

[0009] (1) Disperse CeO2 in anhydrous ethanol-Tris HCl buffer, then add dopamine to it, and stir the reaction under water bath heating to obtain suspension A for later use;

[0010] Al2O3 was dispersed in anhydrous ethanol-water solution, and silane coupling agent KH560 and fluorosilane FAS-13 were added to adjust the pH value. Then the reaction was stirred at room temperature to obtain suspension B for later use.

[0011] Polyurethane was dispersed in anhydrous ethanol-water solution and stirred until homogeneous to obtain a polyurethane solution for later use.

[0012] (2) Mix suspension B with polyurethane solution, and after mixing evenly, add suspension A and stir to mix evenly to obtain spray liquid; apply spray liquid to the surface of object and cure rapidly at room temperature to obtain CeO2-PDA / Al2O3@polyurethane superhydrophobic coating.

[0013] Preferably, in step (1) suspension A, the mass ratio of CeO2, anhydrous ethanol-Tris HCl buffer, and dopamine is 0.60–1.20: 18.95–37.90: 0.16–0.32;

[0014] The CeO2 has a particle size of 20–50 nm;

[0015] The water bath heating temperature is 60-65℃, and the stirring reaction time is 2-4 hours.

[0016] Preferably, in step (1) suspension B, the mass ratio of Al2O3, anhydrous ethanol-water solution, silane coupling agent KH560, and fluorosilane FAS-13 is (0.60~1.20):(10.27~13.85):(0.15~0.25):(0.25~0.35);

[0017] The particle size of the Al2O3 is 20–50 nm;

[0018] The pH value is adjusted to 9.0–10.0;

[0019] The concentration of the anhydrous ethanol-water solution is 82.55–93.87 wt%.

[0020] The reaction time is 2 to 4 hours.

[0021] Preferably, in step (1), the final concentration of the polyurethane solution is 7.97–14.77 wt%.

[0022] The concentration of the anhydrous ethanol-water solution is 82.55–93.87 wt%.

[0023] Preferably, in step (2), the mass ratio of suspension A, suspension B and polyurethane solution is (6.0-6.30):(2.89-2.92):(3.01-3.25).

[0024] Preferably, in step (2), the stirring time is 2 to 4 hours.

[0025] Preferably, in step (2), the curing time is 2 to 3 hours.

[0026] This invention also provides the application of the above-mentioned CeO2-PDA / Al2O3@polyurethane superhydrophobic coating in substrate coating.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) The CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared by this invention is a superhydrophobic coating with high surface stability that can be cured by room temperature spraying. The maximum contact angle between the coating surface and water is 161.6°, and the minimum roll-off angle is 3.2°. In addition, the coating has outstanding advantages such as room temperature spray curing, high surface stability, non-agglomeration of surface nanoparticles, long aging time, and good weather resistance. In the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, the presence of CeO2 improves the weather resistance of the synthesized superhydrophobic coating, and the introduction of dopamine effectively improves the surface stability of the superhydrophobic coating, inhibits the agglomeration of surface nanoparticles, and effectively improves the aging time of the superhydrophobic coating. Therefore, the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating has good application prospects in the superhydrophobic treatment of object surfaces and has strong practical functions and industrial promotion value.

[0029] (2) The CeO2-PDA / Al2O3 / polyurethane emulsion prepared in this invention can be stored for a long time at room temperature. This is due to the surface modification of nano CeO2 by polydopamine and the hydrophobic modification of nano Al2O3 by silane coupling agent KH560, which inhibits the agglomeration of nanoparticles. Furthermore, the addition of fluorosiloxane FAS-13 and silane coupling agent KH560 forms a hydrophobic layer on the surface of polyurethane after the nanoparticles are cured, which reduces the direct contact between the coating and water molecules and improves the anti-corrosion performance of the coating.

[0030] (3) The CeO2-PDA / Al2O3 micro-nanoparticles prepared by this invention have good ultraviolet absorption performance, so that the prepared coating does not show significant changes in its contact angle and roll-off angle under 254nm ultraviolet light irradiation for 1 hour, maintaining good superhydrophobicity and weather resistance, overcoming the problem that polyurethane is prone to aging under ultraviolet light irradiation, and effectively increasing the aging time of the coating.

[0031] (4) The polyurethane prepared by this invention is chemically bonded to the hydrophobically modified nanoparticles, which solves the problem of the inorganic nanoparticles not being tightly connected to the main components, and enhances the stability and wear resistance of the coating surface. After 50 wear cycles, no significant changes were observed in the contact angle and roll-off angle of the coating.

[0032] (5) The CeO2-PDA / Al2O3@polyurethane superhydrophobic coating of the present invention can be cured at room temperature. Compared with the prior art, which requires heating devices such as forced-air drying ovens and vacuum drying ovens for curing, the production cost is greatly increased. This operation benefits from the fact that the main coating polyurethane can be cured at room temperature (25°C), which makes the substrate and the coating itself have a strong adhesion, effectively saving production costs and has the value of realizing large-scale industrialization. Attached Figure Description

[0033] Figure 1 Schematic diagram for preparing CeO2-PDA / Al2O3@polyurethane superhydrophobic coating.

[0034] Figure 2 Infrared spectra of CeO2-PDA / Al2O3@polyurethane superhydrophobic coatings.

[0035] Figure 3 To analyze the particle size of nano-Al2O3 before (Al) and after (K-Al) modification with silane coupling agent in the preparation of CeO2-PDA / Al2O3@polyurethane superhydrophobic coating.

[0036] Figure 4 The changes in contact angle before (a) and after (b) irradiation with ultraviolet light (254nm) for 1 hour to prepare CeO2-PDA / Al2O3@polyurethane superhydrophobic coating.

[0037] Figure 5 The contact angle of CeO2-PDA / Al2O3@polyurethane superhydrophobic coating changes with the number of rubs.

[0038] Figure 6 Thermal imaging of dopamine in CeO2-PDA / Al2O3@polyurethane superhydrophobic coatings (using a xenon lamp (0.1w / cm²)) 2 Before (a) and after (b) 150s of irradiation.

[0039] Figure 7 The contact angle is the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 1.

[0040] Figure 8 The roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 1.

[0041] Figure 9 The contact angle is the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 2.

[0042] Figure 10 The roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 2.

[0043] Figure 11 The contact angle is the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 3.

[0044] Figure 12 The roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 3.

[0045] Figure 13The contact angle is the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 4.

[0046] Figure 14 The roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 4.

[0047] Figure 15 The contact angle is the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 5.

[0048] Figure 16 The roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared in Example 5. Detailed Implementation

[0049] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0050] Example 1:

[0051] Figure 1 To illustrate the principle of preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, this embodiment is based on... Figure 1 The process described above is used to prepare the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. The specific steps are as follows:

[0052] (1) Disperse 1.2g of CeO2 with a particle size of 20nm in a mixed solution of 10mL of anhydrous ethanol and 30mL of Tris HCl buffer, sonicate for 30min to mix evenly, then add 0.24g of dopamine and continue to sonicate to mix evenly, then react for 4h in a water bath at 60℃. After the reaction is completed, suspension A is obtained for later use.

[0053] 1.2 g of Al2O3 with a particle size of 20 nm was dispersed in a mixed solution of 15 mL of anhydrous ethanol and 2 mL of deionized water. Then, 0.25 g of silane coupling agent KH560 and 0.35 g of fluorosiloxane FAS-13 were added. After sonication for 30 min, 25 vol-% ammonia was added to slowly adjust the pH value to 9-10. The mixture was then reacted at room temperature for 2 h to obtain suspension B for later use.

[0054] Weigh 1.2g of polyurethane and disperse it in 15mL of anhydrous ethanol and 2mL of deionized water. Mix and stir for 2 hours to obtain a polyurethane solution for later use.

[0055] (2) After mixing the suspension B obtained in step (1) with the polyurethane solution, stir evenly at room temperature for 1 hour, then add suspension A and continue stirring for 1 hour. After mixing evenly, a spraying liquid is obtained. Then, the obtained spraying liquid is evenly sprayed onto the fabric surface through a spray gun and cured at room temperature for 2 hours to obtain a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. After the coating dries, the static contact angle of the coating surface with water is tested using a contact angle meter.

[0056] Figure 2 Infrared spectra of CeO2-PDA / Al2O3@polyurethane superhydrophobic coatings were obtained. As can be seen from the figure, the silane coupling agent KH560 and the fluorosilane FAS-13 were successfully hydrolyzed and grafted onto the surface of nano-Al2O3 to achieve hydrophobic modification.

[0057] Figure 3 Particle size analysis was performed on nano-Al2O3 in CeO2-PDA / Al2O3@polyurethane superhydrophobic coating before (Al) and after (K-Al) modification with silane coupling agent. As can be seen from the figure, thanks to the grafting modification of nano-Al2O3 by silane coupling agent KH560, the aggregation phenomenon of particles was effectively improved, and the dispersion of nanoparticles in the emulsion was more stable and uniform than before modification.

[0058] Figure 4 The changes in contact angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating before (a) and after (b) irradiation with ultraviolet light (254nm) for 1 hour were shown in the figure. As can be seen from the figure, thanks to the excellent ultraviolet absorption performance of polydopamine and inorganic nanoparticles, the contact angle and roll-off angle did not change significantly after irradiation with 254nm ultraviolet light for 1 hour, which effectively enhanced the weather resistance of the coating.

[0059] Figure 5 The contact angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating changes with the number of friction cycles. As can be seen from the figure, thanks to the chemical bond between polydopamine, polyurethane and inorganic nanoparticles, the contact angle and roll-off angle do not change significantly after 50 friction cycles, effectively enhancing the wear resistance of the coating.

[0060] Figure 6 Thermal imaging of dopamine in CeO2-PDA / Al2O3@polyurethane superhydrophobic coatings (using a xenon lamp (0.1w / cm²)) 2 Before (a) and after (b) 150s of irradiation; As can be seen from the figure, thanks to the high viscosity dopamine completing the polymerization on the surface of CeO2 nanoparticles, natural melanin is formed, which effectively absorbs the xenon lamp light source and increases the surface temperature of the coating, proving that polydopamine has been successfully introduced into the coating.

[0061] Figure 7 and8 The figures show the contact angle and roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. As can be seen from the figures, the contact angle is 161.4° and the roll-off angle is 3.2°. These good contact and roll-off angles indicate that the coating's special surface properties make it almost impossible for water droplets to adhere upon contact, allowing them to easily roll freely back and forth on the coating surface. After 1 hour of UV irradiation or 50 cycles of rubbing, no significant changes were observed in the contact and roll-off angles. The prepared superhydrophobic coating also exhibits excellent superhydrophobicity, weather resistance, and wear resistance.

[0062] Example 2:

[0063] Figure 1 To illustrate the principle of preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, this embodiment is based on... Figure 1 The process described above is used to prepare the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. The specific steps are as follows:

[0064] (1) Disperse 1.2g of CeO2 with a particle size of 20nm in a mixed solution of 10mL of anhydrous ethanol and 30mL of Tris HCl buffer, sonicate for 30min to mix evenly, then add 0.24g of dopamine and continue to sonicate to mix evenly, then react for 4h in a water bath at 60℃. After the reaction is completed, suspension A is obtained for later use.

[0065] 0.6 g of Al2O3 with a particle size of 20 nm was dispersed into a mixed solution of 15 mL of anhydrous ethanol and 2 mL of deionized water. Then, 0.25 g of silane coupling agent KH560 and 0.35 g of fluorosiloxane FAS-13 were added. After sonication for 30 min, 25 vol-% ammonia was added to slowly adjust the pH value to 9-10. The mixture was then reacted at room temperature for 2 h to obtain suspension B, which was then set aside for later use.

[0066] Weigh 1.2g of polyurethane and disperse it in 15mL of anhydrous ethanol and 2mL of deionized water. Mix and stir for 2 hours to obtain a polyurethane solution for later use.

[0067] (2) After mixing the suspension B obtained in step (1) with the polyurethane solution, stir evenly at room temperature for 1 hour, then add suspension A and continue stirring for 1 hour. After mixing evenly, a spraying liquid is obtained. Then, the obtained spraying liquid is evenly sprayed onto the fabric surface through a spray gun and cured at room temperature for 2 hours to obtain a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. After the coating dries, the static contact angle of the coating surface with water is tested using a contact angle meter.

[0068] Figure 9 and 10The figures show the contact angle and roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, respectively. As can be seen from the figures, the contact angle is 160.2° and the roll-off angle is 3.5°. After 1 hour of UV irradiation or 50 cycles of friction, no significant changes were observed in the contact angle and roll-off angle. The prepared superhydrophobic coating also exhibits good superhydrophobicity, weather resistance, and wear resistance.

[0069] Example 3:

[0070] Figure 1 To illustrate the principle of preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, this embodiment is based on... Figure 1 The process described above is used to prepare the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. The specific steps are as follows:

[0071] (1) Disperse 1.2g of CeO2 with a particle size of 20nm in a mixed solution of 10mL of anhydrous ethanol and 30mL of Tris HCl buffer, sonicate for 30min to mix evenly, then add 0.24g of dopamine and continue to sonicate to mix evenly, then react for 4h in a water bath at 60℃. After the reaction is completed, suspension A is obtained for later use.

[0072] 1.8 g of Al2O3 with a particle size of 20 nm was dispersed into a mixed solution of 15 mL of anhydrous ethanol and 2 mL of deionized water. Then, 0.25 g of silane coupling agent KH560 and 0.35 g of fluorosiloxane FAS-13 were added. After sonication for 30 min, 25 vol-% ammonia was added to slowly adjust the pH value to 9-10. The mixture was then reacted at room temperature for 2 h to obtain suspension B for later use.

[0073] Weigh 1.2g of polyurethane and disperse it in 15mL of anhydrous ethanol and 2mL of deionized water. Mix and stir for 2 hours to obtain a polyurethane solution for later use.

[0074] (2) After mixing the suspension B obtained in step (1) with the polyurethane solution, stir evenly at room temperature for 1 hour, then add suspension A and continue stirring for 1 hour. After mixing evenly, a spraying liquid is obtained. Then, the obtained spraying liquid is evenly sprayed onto the fabric surface through a spray gun and cured at room temperature for 2 hours to obtain a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. After the coating dries, the static contact angle of the coating surface with water is tested using a contact angle meter.

[0075] Figure 11 and 12The figures show the contact angle and roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, respectively. As can be seen from the figures, the contact angle is 158.2° and the roll-off angle is 4.5°. After 1 hour of UV irradiation or 50 cycles of friction, no significant changes were observed in the contact angle and roll-off angle. The prepared superhydrophobic coating also exhibits good superhydrophobicity, weather resistance, and wear resistance.

[0076] Example 4:

[0077] Figure 1 To illustrate the principle of preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, this embodiment is based on... Figure 1 The process described above is used to prepare the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. The specific steps are as follows:

[0078] (1) Disperse 1.2g of CeO2 with a particle size of 20nm in a mixed solution of 10mL of anhydrous ethanol and 30mL of Tris HCl buffer, sonicate for 30min to mix evenly, then add 0.32g of dopamine and continue to sonicate to mix evenly, then react for 4h in a water bath at 60℃. After the reaction is completed, suspension A is obtained for later use.

[0079] 1.2 g of Al2O3 with a particle size of 20 nm was dispersed into a mixed solution of 15 mL of anhydrous ethanol and 2 mL of deionized water. Then, 0.25 g of silane coupling agent KH560 and 0.35 g of fluorosiloxane FAS-13 were added. After sonication for 30 min, 25 vol-% ammonia was added to slowly adjust the pH value to 9-10. The mixture was then reacted at room temperature for 2 h to obtain suspension B, which was then set aside for later use.

[0080] Weigh 1.2g of polyurethane and disperse it in 15mL of anhydrous ethanol and 2mL of deionized water. Mix and stir for 2 hours to obtain a polyurethane solution for later use.

[0081] (2) After mixing the suspension B obtained in step (1) with the polyurethane solution, stir evenly at room temperature for 1 hour, then add suspension A and continue stirring for 1 hour. After mixing evenly, a spraying liquid is obtained. Then, the obtained spraying liquid is evenly sprayed onto the fabric surface through a spray gun and cured at room temperature for 2 hours to obtain a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. After the coating dries, the static contact angle of the coating surface with water is tested using a contact angle meter.

[0082] Figure 13 and 14The figures show the contact angle and roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, respectively. As can be seen from the figures, the contact angle is 157.1° and the roll-off angle is 5.3°. After 1 hour of UV irradiation or 50 cycles of friction, no significant changes were observed in the contact angle and roll-off angle. The prepared superhydrophobic coating also exhibits good superhydrophobicity, weather resistance, and wear resistance.

[0083] Example 5:

[0084] Figure 1 To illustrate the principle of preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, this embodiment is based on... Figure 1 The process described above is used to prepare the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. The specific steps are as follows:

[0085] (1) Disperse 1.2g of CeO2 with a particle size of 20nm in a mixed solution of 10mL anhydrous ethanol and 30mL Tris HCl buffer, sonicate for 30min to mix evenly, then add 0.016g of dopamine and continue to sonicate to mix evenly, then react for 4h in a 60℃ water bath. After the reaction is complete, obtain suspension A for later use.

[0086] 1.2 g of Al2O3 with a particle size of 20 nm was dispersed into a mixed solution of 15 mL of anhydrous ethanol and 2 mL of deionized water. Then, 0.25 g of silane coupling agent KH560 and 0.35 g of fluorosiloxane FAS-13 were added. After sonication for 30 min, 25 vol-% ammonia was added to slowly adjust the pH value to 9-10. The mixture was then reacted at room temperature for 2 h to obtain suspension B, which was then set aside for later use.

[0087] Weigh 1.2g of polyurethane and disperse it in 15mL of anhydrous ethanol and 2mL of deionized water. Mix and stir for 2 hours to obtain a polyurethane solution for later use.

[0088] (2) After mixing the suspension B obtained in step (1) with the polyurethane solution, stir evenly at room temperature for 1 hour, then add suspension A and continue stirring for 1 hour. After mixing evenly, a spraying liquid is obtained. Then, the obtained spraying liquid is evenly sprayed onto the fabric surface through a spray gun and cured at room temperature for 2 hours to obtain a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. After the coating dries, the static contact angle of the coating surface with water is tested using a contact angle meter.

[0089] Figure 15 and 16The figures show the contact angle and roll-off angle of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, respectively. As can be seen from the figures, the contact angle is 156.5° and the roll-off angle is 6.0°. After 1 hour of UV irradiation or 50 cycles of friction, no significant changes were observed in the contact angle and roll-off angle. The prepared superhydrophobic coating also exhibits good superhydrophobicity, weather resistance, and wear resistance.

[0090] In summary, the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared by this invention has outstanding advantages such as room temperature spray curing, high surface stability, non-agglomeration of surface micro and nano particles, long efficiency, and good weather resistance. The superhydrophobic coating can be prepared at room temperature and has good application prospects for superhydrophobic treatment of object surfaces, possessing strong practical functions and industrial promotion value.

[0091] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a CeO2-PDA / Al2O3@polyurethane superhydrophobic coating, characterized in that, include: (1) CeO2 was dispersed in anhydrous ethanol-TrisHCl buffer, and then dopamine was added to it. The mixture was stirred under water bath heating to obtain suspension A for later use. When preparing suspension A, the mass ratio of CeO2, anhydrous ethanol-TrisHCl buffer and dopamine was 0.60~1.20:18.95~37.90:0.16~0.

32. The CeO2 has a particle size of 20~50nm; The water bath heating temperature is 60~65℃, and the stirring reaction time is 2~4h; Al2O3 was dispersed in anhydrous ethanol-water solution, and silane coupling agent KH560 and fluorosilane FAS-13 were added to adjust the pH value. Then the reaction was stirred at room temperature to obtain suspension B for later use. When preparing suspension B, the mass ratio of Al2O3, anhydrous ethanol-water solution, silane coupling agent KH560, and fluorosilane FAS-13 is (0.60~1.20):(10.27~13.85):(0.15~0.25):(0.25~0.35). The particle size of the Al2O3 is 20~50nm; The pH value is adjusted to 9.0~10.0; Polyurethane was dispersed in anhydrous ethanol-water solution and stirred until homogeneous to obtain a polyurethane solution for later use. (2) Mix suspension B with polyurethane solution, and after mixing evenly, add suspension A and stir to mix evenly to obtain spray liquid; The spray liquid was applied to the surface of the object and cured rapidly at room temperature to obtain the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating. The mass ratio of suspension A, suspension B and polyurethane solution is (6.0~6.30):(2.89~2.92):(3.01~3.25).

2. The method for preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating according to claim 1, characterized in that, In step (1), during the preparation of suspension B, the concentration of the anhydrous ethanol-water solution is 82.55~93.87 wt%. The reaction time is 2-4 hours.

3. The method for preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating according to claim 1, characterized in that, In step (1), the final concentration of the polyurethane solution is 7.97~14.77 wt%. The concentration of the anhydrous ethanol-water solution is 82.55~93.87 wt%.

4. The method for preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating according to claim 1, characterized in that, In step (2), the stirring time is 2 to 4 hours.

5. The method for preparing the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating according to claim 1, characterized in that, In step (2), the curing time is 2~3 hours.

6. The CeO2-PDA / Al2O3@polyurethane superhydrophobic coating prepared by the method according to any one of claims 1 to 5, characterized in that, The CeO2-PDA / Al2O3@polyurethane superhydrophobic coating has a rough surface resembling a lotus leaf; the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating is based on polyurethane, with CeO2-PDA and hydrophobically modified Al2O3 nanoparticles dispersed on the main coating; the CeO2-PDA is polydopamine coated on the CeO2 surface.

7. The application of the CeO2-PDA / Al2O3@polyurethane superhydrophobic coating as described in claim 6 in substrate coating.

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