Durable transparent omniphobic coating with antireflective effect and method of making the same

Abstract

This invention discloses a durable transparent superhydrophobic coating with antireflective properties and its preparation method, relating to the field of coating technology. The transparent superhydrophobic coating includes a primer layer and a topcoat layer. The primer layer comprises a porous structure, and the topcoat layer is configured to be embedded in the porous structure and cover the primer layer. The primer layer comprises a material prepared from the following raw materials in parts by weight: 40-60 parts polymer resin, 5-10 parts pore-forming agent, 2-5 parts micro / nano-scale reinforcing filler, 0.5-1 parts dispersant, 1-50 parts curing agent, and 1-50 parts diluent. This invention constructs a porous framework in the primer layer using crosslinkable polymer resin, pore-forming agent, and micro / nano-scale reinforcing filler, and embeds a low surface energy topcoat layer into the porous structure to form a mechanical interlock, thereby achieving the purpose of constructing an effective support structure and interlayer bonding mechanism in the superhydrophobic coating, thus improving mechanical strength and preventing the overall peeling and failure of the topcoat layer.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a durable transparent superhydrophobic coating with antireflective properties and its preparation method. Background Technology

[0002] With the advancement of materials science, superhydrophobic and superoleophobic (superamphopretic) coatings have become a research hotspot due to their broad application prospects in self-cleaning, anti-icing, anti-fouling, and oil-water separation. An ideal superamphopretic coating needs to possess extremely high static contact angles (e.g., water contact angle > 150°, oil contact angle > 150°) and extremely low roll-off angles. For transparent superamphopretic coatings, they also need high light transmittance, excellent mechanical stability, and good adhesion to meet the needs of complex practical application environments.

[0003] Currently, the mainstream technical approach for constructing superhydrophobic surfaces mainly relies on the construction of micro / nano-level hierarchical rough structures and the modification with low surface energy materials. However, existing technologies for preparing transparent superhydrophobic coatings still face several prominent problems and shortcomings in terms of achieving industrial application:

[0004] (1) The contradiction between coating mechanical strength and superhydrophobic properties: To construct the required micro-nano rough structures, the most common method used by researchers is to directly spray low surface energy nanoparticle dispersions or sols onto the surface of glass substrates. Due to the strong chemical inertness of fluorine-containing substances, the interactions between nanoparticles and between nanoparticles and the substrate are mainly van der Waals forces (i.e., physical adsorption), and there is a lack of support from film-forming substances. Therefore, although the coatings formed by this method have excellent superhydrophobic properties, they usually have very low mechanical strength and poor wear resistance and scratch resistance. Slight physical contact or friction can destroy its fine microstructure, leading to rapid decay or even failure of superhydrophobic properties and short service life. To solve this problem, some researchers use a one-step spraying method that mixes low surface energy nanoparticles with film-forming substances such as epoxy, polyurethane, and PDMS. Although this method solves the adhesion problem, it is easy for the low surface energy powder to be coated by the cured resin, thereby significantly reducing the superhydrophobic properties of the coating.

[0005] (2) Interlayer adhesion and durability issues: To resolve the contradiction between mechanical properties and superhydrophobicity, some technical solutions employ a composite structure of "primer + topcoat". The primer's main function is to enhance adhesion to the substrate and provide some mechanical support, while the topcoat provides superhydrophobic properties. However, the topcoat layer providing superhydrophobic properties (usually a nanoparticle stack layer) often has weak cohesion and poor film-forming properties, resulting in insufficient bonding with the primer. Under external stress or environmental changes, the topcoat layer is prone to peeling off completely, leading to functional failure. Some scholars have proposed spraying the topcoat before the primer is completely dry to solve this problem. While this approach is theoretically feasible, "not completely dry" is a difficult standard to quantify, making it challenging to implement in practice. Insufficient drying can cause nanoparticles to be encapsulated, affecting light transmittance; excessive drying, however, still fails to solve the adhesion problem.

[0006] (3) The challenge of balancing transmittance and surface roughness: While micro- and nano-rough structures impart superhydrophobic properties to the surface, they also cause strong light scattering, resulting in a significant decrease in the transmittance of the coating. This is a fatal flaw for applications requiring high transmittance (such as optical lenses, solar cell covers, and architectural glass). Although adding transparent nanofillers directly to the resin can improve mechanical properties to some extent, the uneven dispersion or random stacking of fillers often makes it difficult to precisely control the scale and distribution of roughness, thus failing to achieve both high transmittance and superhydrophobicity simultaneously.

[0007] (4) Complexity of process and cost: Existing high-performance transparent superhydrophobic coating preparation processes involve complex and expensive equipment and processes such as high-temperature sintering, template method, vapor deposition, and photolithography, which are difficult to meet the needs of large-scale, low-cost industrial production and construction.

[0008] Therefore, there is an urgent need in this field for a novel superhydrophobic coating structure that combines high mechanical strength, high light transmittance, excellent durability, and simple preparation process to overcome the above-mentioned defects in the prior art. Summary of the Invention

[0009] The purpose of this invention is to provide a durable transparent superhydrophobic coating with anti-reflective properties and its preparation method. By constructing a porous framework in the primer layer using crosslinkable polymer resin, pore-forming agent and micro-nano reinforcing filler, and embedding a low surface energy topcoat layer into the porous structure to form a mechanical interlock, this invention solves the technical problems of insufficient mechanical strength and easy overall peeling failure of the topcoat layer in the prior art due to the lack of effective support structure and interlayer bonding mechanism in superhydrophobic coatings.

[0010] First, this embodiment of the invention provides a durable transparent superhydrophobic coating with anti-reflective properties, comprising a primer layer and a topcoat layer. The primer layer includes a porous structure, and the topcoat layer is configured to be embedded in the porous structure and cover the primer layer.

[0011] The primer layer comprises a material prepared from the following raw materials in parts by weight: 40-60 parts polymer resin, 5-10 parts pore-forming agent, 2-5 parts micro / nano-scale reinforcing filler, 0.5-1 part dispersant, 1-50 parts curing agent, and 1-50 parts diluent;

[0012] The curing agent can undergo a cross-linking reaction with the polymer resin to form a porous structure.

[0013] Specifically, in this embodiment of the invention, a three-dimensional network framework is constructed through the cross-linking reaction of 40-60 parts of polymer resin and 1-50 parts of curing agent in the primer formulation. This ratio range ensures the formation of a continuous support network to lock in 5-10 parts of porogen and 2-5 parts of micro-nano-scale reinforcing filler, while avoiding excessive resin which would completely seal the porogen and make it difficult to wash off. If the resin content is too low, the network will be discontinuous and the mechanical support will be insufficient. If the curing dosage is inappropriate, the cross-linking density will be unbalanced, affecting the pore stability. The porogen content is precisely controlled at 5-10 parts, which can form sufficient micro-nano open pores for the topcoat to embed after washing. If it is too low, the embedding will be insufficient and the interlayer bonding force will be weak. If it is too high, the porosity will be too large, resulting in a decrease in the support force of the framework. The micro-nano reinforcing filler is embedded in the cross-linking network at 2-5 parts, which can effectively improve the hardness and wear resistance, form a primary rough structure framework, and avoid excessive filler which would hinder the continuity of resin cross-linking or cause agglomeration and sedimentation.

[0014] 0.5 to 1 part dispersant ensures uniform dispersion of fillers to maintain optical transparency. Insufficient amount results in poor dispersion and can easily lead to phase separation and light scattering. Excessive amount may remain on the pore surface and affect the penetration of the topcoat. The topcoat layer is composed of low surface energy nanoparticles embedded in the porous structure of the primer and then covering it. This allows the nanoparticles to construct a secondary nano-rough structure to provide superhydrophobic and dihydrophobic properties, while their roots are anchored inside the primer skeleton to form a mechanical interlock. This solves the defects of functional layers that only adhere to the surface and have weak cohesion and are easy to peel off as a whole. The porous structure of the primer and the secondary rough structure work together to form an optical gradient refractive index layer, which allows light to transition smoothly at the interface rather than abruptly, reducing scattering and achieving a transmittance higher than that of bare glass. At the same time, the cross-linked network and reinforcing fillers work together to give the coating an excellent balance of mechanical strength, substrate adhesion and superhydrophobic and dihydrophobic properties.

[0015] As an optional embodiment, the polymer resin includes at least one of epoxy resin, acrylic resin, polyurethane resin, acrylic-polyurethane resin, silicone resin, and fluorocarbon resin;

[0016] The pore-forming agent includes at least one of polyethylene glycol, PEG-400, PEG-600, and PEG-1000;

[0017] The micro-nano-scale reinforcing filler includes at least one of fumed silica and precipitated silica.

[0018] For example, epoxy resin can be combined with curing agents such as modified cycloaliphatic amines and polyetheramine D-230; acrylic resin can be combined with curing agents such as HDI trimer and amino resin; polyurethane resin can be combined with curing agents such as HDI trimer and DI adduct; acrylic-polyurethane resin can be combined with curing agents such as waterborne HDI trimer and blocked isocyanate; silicone resin can be combined with curing agents such as tetrabutyl titanate and dibutyltin dilaurate; and fluorocarbon resin can be combined with curing agents such as HDI trimer and HDI trimer.

[0019] In this embodiment of the invention, the substrate adaptability and curing conditions are matched by flexibly selecting the types of polymer resins. Epoxy resin provides excellent adhesion and chemical bonding ability, acrylic resin and polyurethane resin impart good flexibility and weather resistance, acrylic-polyurethane combines the advantages of both, silicone resin brings high temperature resistance and hydrophobic properties, and fluorocarbon resin provides super weather resistance and anti-fouling properties. The availability of multiple resins ensures that the formulation can select the optimal film-forming material and form covalent bonds according to the surface chemical properties of different substrates such as glass, metal, and plastic.

[0020] The pore-forming agent is selected from at least one of PEG-400, PEG-600, or PEG-1000. The pore size and distribution are precisely controlled by the difference in their molecular chain lengths. PEG-400 has a small molecular weight, strong water solubility, and is easy to elute to form nanoscale pores. PEG-1000 has a long molecular chain and a slow dissolution rate, but can construct more stable micron-scale macropores. PEG-600 serves as a balancing intermediate. By using different molecular weight PEGs in synergy or by selecting a single one, the pore structure can be customized to meet the different penetration depths and roughness requirements of the topcoat. At the same time, the hydroxyl groups of polyethylene glycol can form hydrogen bonds with the resin prepolymer and be stably anchored inside the network during the cross-linking and curing process, ensuring that open rather than closed interconnected channels are formed after elution.

[0021] The micro-nano-scale reinforcing filler is selected from at least one of fumed silica and precipitated silica. Fumed silica has small particle size (15~50nm), high purity, and good dispersibility, which can construct a fine nano-rough structure and minimize light scattering. Precipitated silica has lower cost and a wide particle size distribution (50~1300nm), which can provide micron-level skeleton support. The two are used together to enhance the hardness and wear resistance of the coating at different scales. The silanol groups on its surface participate in the reaction during the resin crosslinking process, so that the filler is firmly embedded in the pore wall skeleton, which not only constitutes the primary rough structure but also serves as a mechanical support point. Together with the secondary structure formed by the topcoat nanoparticles, it achieves the unity of superhydrophobic and adiaphragmatic properties and mechanical strength.

[0022] As an optional implementation, the diluent includes at least one of water, xylene, n-butanol, ethyl acetate, butyl acetate, anhydrous ethanol, acetone, diglycidyl ether, 1,4-butanediol diglycidyl ether, and neopentyl glycol diglycidyl ether.

[0023] Specifically, this invention achieves precise control over the coating's application performance and film-forming quality by carefully selecting solvents with different evaporation rates and reactivity. Water is used as an environmentally friendly diluent in the water-based resin system. Fast-evaporating solvents such as xylene, ethyl acetate, and acetone quickly reduce the system viscosity and accelerate surface drying. Medium- to slow-evaporating solvents such as n-butanol, butyl acetate, and anhydrous ethanol extend the leveling time to ensure full film spreading, while simultaneously creating a volatility gradient to prevent cratering or blistering due to sudden solvent evaporation. Crucially, diglycidyl ether, 1,4-butanediol diglycidyl ether, and neopentyl glycol diglycidyl ether are used. Reactive diluents such as glycidyl ethers have epoxy groups that participate in the resin crosslinking reaction during the curing stage, becoming part of the network structure. This reduces the viscosity of the system, improves workability, and avoids the impact of residual micropores on the density and transparency of the coating after the complete evaporation of traditional inactive solvents. It also reduces VOC emissions. By selecting reactive diluents with different chain lengths and functionalities, the crosslinking density and coating flexibility can be finely adjusted. This allows the entire diluent system to synergistically optimize pore formation, topcoat embedding, and the optical and mechanical properties of the final coating while ensuring that the primer viscosity is within the optimal range of 15-20s.

[0024] As an optional implementation, the particle size of the micro / nano-scale reinforced filler is 15 nm to 1300 nm, and the molecular weight of the pore-forming agent is 400 to 1300.

[0025] Specifically, the particle size of the micro / nano-scale reinforced filler is precisely controlled within the range of 15 nm to 1300 nm, ensuring a synergistic match with the porogen with a molecular weight of 400 to 1300. Smaller particles (15-100 nm) fill the gaps in the resin network and connect with the nanopores after the porogen is washed away, constructing a fine nano-rough structure and minimizing light scattering. Larger particles (100-1300 nm) act as micron-scale skeletal support points, enhancing coating hardness and wear resistance, and forming micron-scale interconnected channels after the porogen is washed away, ensuring the topcoat penetration depth and interlayer mechanical interlocking strength. The selection of the porogen's molecular weight of 400-1300 takes into account water solubility. Regarding properties and pore stability, lower molecular weight PEG-400 can be quickly eluted to form fine nanopores, but the pore wall strength is slightly weaker. Higher molecular weight PEG-1000 has a slower dissolution rate but can construct more stable micron-sized macropores. This range allows the porogen to be stably anchored in the cured network and completely dissolved in a 30~40℃ water bath. The pore size distribution formed after elution forms a gradient complement to the filler particle size range, jointly constructing a multi-level pore-rough structure spanning from nano to micron. This provides sufficient space for topcoat embedding and avoids the collapse of the skeleton due to excessively large pores or the obstruction of penetration due to excessively small pores through precise size matching.

[0026] As an optional implementation, the topcoat layer comprises a material prepared from modified silica nanosol and fluorinated silane, wherein the fluorinated silane accounts for 1-5% of the weight percentage of the topcoat layer raw materials;

[0027] The modified silica nanosol comprises silica nanoparticles and a solvent, wherein the solvent comprises at least one of isopropanol, ethanol, and methanol.

[0028] Specifically, in this embodiment of the invention, a secondary modification of the modified silica nanosol is performed using a precise dosage of 1-5% fluorosilane. This achieves the dual functions of surface energy regulation and enhanced chemical bonding. The 1-5% addition ensures that the perfluorodecyl or perfluorooctyl segments fully cover the surface of the silica nanoparticles to provide stable superhydrophobic and oleophobic properties, while avoiding particle agglomeration or film embrittlement caused by excessive fluorosilane self-polymerization and crosslinking. Too low a dosage results in incomplete surface modification and insufficient oleophobic effect, while too high a dosage causes excess material to remain in the pores, thus reducing interlayer adhesion. The modified silica nanosol uses at least one of isopropanol, ethanol, and methanol as a dispersion solvent. Its low surface tension and moderate evaporation rate ensure efficient penetration and wetting of the porous structure of the primer. The hydrophobic segments of isopropanol can temporarily shield the nanoparticles. The surface hydroxyl groups reduce agglomeration, while the strong polarity of ethanol and methanol promotes the uniform spreading and bonding reaction of silanols after hydrolysis of fluorinated silanes on the pore walls. The solvent evaporation gradient achieves controllable drying through boiling point differences, avoiding rapid shrinkage that could destroy the interlocking structure. The silica nanoparticles in the sol themselves have a particle size of 10-20 nm. After solvent evaporation, they randomly accumulate on the pore surface to form a secondary rough structure. The residual hydroxyl groups on their surface can undergo condensation reactions with the hydrolysis products of fluorinated silanes and the hydroxyl groups in the primer network. Through Si-O-Si bonds, the topcoat is chemically anchored to the primer framework, making the nanoparticles both superhydrophobic functional units and "rivets" connecting the two layers. This achieves synergistic enhancement of mechanical interlocking and chemical bonding, thereby giving the coating extremely low surface energy and stable durability while ensuring that the topcoat cannot form a film on its own.

[0029] Taking perfluorodecyltriethoxysilane as an example, the reaction mechanism of this invention embodiment is as follows: Figure 1 As shown: Perfluorosilanes first hydrolyze under the action of moisture adsorbed in the air or on the surface of the primer to generate perfluorosilanol (-SiOH). Then, the silanol undergoes a condensation reaction with the hydroxyl groups on the surface of the primer to form stable Si-OC bonds, grafting the perfluoro segments onto the primer and further reducing the surface energy. At the same time, perfluorosilanol can also undergo a condensation reaction with the hydroxyl groups of the micro-nano-scale reinforcing fillers in the primer and the remaining hydroxyl groups on the surface of the low surface energy modified silica in the topcoat to form Si-O-Si bonds. This allows them to intertwine with the silica particles to form a network structure, further strengthening the interlocking structure of the primer and topcoat through chemical bonding and improving adhesion.

[0030] It should be noted that in other embodiments, other nanoparticles capable of achieving low surface energy, such as fluorinated TiO2, fluorinated ZnO, and organic fluoropolymer nanospheres, can be used, and no limitation is made here.

[0031] As an optional implementation, the fluorinated silane includes at least one of perfluorodecyltriethoxysilane, perfluorooctyltriethoxysilane, trifluoropropyltrimethoxysilane, and perfluorooctylethyltrichlorosilane.

[0032] As an optional implementation, the modified silica nanosol has a solid content of 2-30% and the silica nanoparticles have a particle size of 10-20 nm.

[0033] The solid content of the modified silica nanosol is precisely controlled within the range of 2-30% to ensure that the topcoat has sufficient nanoparticle concentration to fill the pores of the primer and form a secondary rough structure, while maintaining low viscosity for efficient penetration. If the solid content is below 2%, the number of nanoparticles is insufficient to construct a complete superhydrophobic surface, requiring multiple coats and resulting in unstable performance. If it is above 30%, the sol viscosity increases significantly, hindering penetration into the pores and easily accumulating on the surface to form a film, leading to decreased light transmittance and clogging of pores, weakening interlayer bonding. The particle size of the silica nanoparticles is limited to 10-20 nm to ensure stable dispersion in the sol. To avoid agglomeration, the particles can precisely match the pore size formed by the pore-forming agent and micro / nano fillers, uniformly stacking on the pore wall surface to construct a nanoscale rough structure. If the particle size is less than 10 nm, the particles are prone to agglomeration and the constructed rough scale is insufficient to achieve superhydrophobicity. If it is greater than 20 nm, the roughness after the particles are stacked in the pores will be too large, increasing light scattering and reducing transparency. It may also exceed the pore's capacity and fail to embed effectively. This particle size range works synergistically with the solid content to ensure that the nanoparticles can form a dense and uniform secondary rough structure on the pore surface after infiltration, maximizing optical transparency while ensuring superhydrophobic and amphoteric properties.

[0034] Secondly, this invention also provides a method for preparing a durable transparent superhydrophobic coating with antireflective properties, comprising the following steps:

[0035] S1: The polymer resin, pore-forming agent, dispersant and part of the diluent are stirred, and the micro-nano-scale reinforcing filler is stirred and dispersed under stirring.

[0036] S2: Add curing agent and remaining diluent to the dispersed raw materials and continue dispersing to obtain primer slurry;

[0037] S3: Apply the primer slurry to the substrate and then pre-cure it;

[0038] S4: Immerse the pre-cured substrate with primer in deionized water at 30~40℃ to form a porous structure. Then clean and cure the porous structure to obtain the primer layer.

[0039] S5: A topcoat slurry is obtained by mixing modified silica nanosol and fluorinated silane;

[0040] S6: The topcoat slurry is applied over the primer layer, and after the topcoat slurry fills the porous structure and dries, a topcoat layer is formed, resulting in a double-hydrophobic coating.

[0041] As an optional implementation, the coating in S3 includes at least one of spraying, scraping, brushing, and roller coating, and the wet film thickness after coating is 20~100μm. The pre-curing includes allowing the wet film to stand and level until it reaches a "finger-dry" state.

[0042] The curing described in S4 includes drying at room temperature for 0.5 to 2 hours.

[0043] As an optional implementation, S6, applying the topcoat slurry over the primer layer includes: using at least one of the following wiping materials—non-woven fabric, microfiber lint-free cloth, and sponge—to saturate the topcoat slurry and applying it to the primer layer at a rate of 0.1~0.5 kgf / cm². 2 Apply pressure and wipe 2-5 times consecutively.

[0044] The preparation method of this invention forms a tenon-and-mortise interlocking structure through stepwise construction and precise control of critical states. In S1~S2, a staged dispersion process is used to first premix the polymer resin, pore-forming agent and dispersant in a diluent, and then slowly add micro-nano-scale reinforcing filler for high-speed dispersion to ensure that the filler surface is fully wetted by the resin and avoid agglomeration. Finally, a curing agent is mixed in to prevent premature cross-linking from affecting the dispersion effect. In S3, the primer slurry is coated and immediately pre-cured to the "finger-dry state". This critical degree of cross-linking allows the resin to initially form a three-dimensional network and lock the positions of the pore-forming agent and filler, but it is not completely densified and retains sufficient molecular chain mobility and pore permeability. If the curing is too excessive, the network will be too dense and the pore-forming agent will be difficult to wash off. If the curing is insufficient, the coating will have poor mechanical strength and will be prone to swelling and deformation during pore formation.

[0045] S4 immerses the pre-cured coating in deionized water at 30~40℃. Temperatures above 30℃ can accelerate the dissolution and diffusion of PEG and shorten the pore-forming time, while temperatures below 40℃ can prevent the resin network from over-swelling or softening. Gentle stirring at 50-200 r / min allows water molecules to penetrate and dissolve PEG evenly, forming open and interconnected micro-nano pores. Soaking for 2 hours ensures that the pore-forming agent is completely washed away. Then, deionized water and ethanol are used to rinse away residual PEG and quickly replace water. After drying at room temperature, a porous primer layer is obtained.

[0046] S5 involves mixing modified silica nanosol with a solid content of 2-30% and a particle size of 10-20 nm with 1-5% fluorinated silane, allowing the silane to be pre-grafted onto the surface of the nanoparticles through hydrolysis and condensation, thereby reducing their surface energy and enhancing their chemical bonding ability with the primer; S6 involves applying the topcoat slurry by wiping with shear force instead of simple spraying or brushing, at a concentration of 0.3-0.5 kgf / cm². 2Under pressure, the slurry is forced to overcome the air resistance in the pores and actively penetrate into the porous structure. It uses capillary action to fill the deep pores. After the solvent evaporates, the nanoparticles are mechanically locked to the pore walls to form a three-dimensional interlock. If only the surface is coated, effective embedding cannot be formed. Too many wiping times or too much pressure may destroy the already formed pore structure. This step allows the topcoat to retain its inability to form a film on its own while achieving a strong bond with the primer, ultimately resulting in a composite coating that combines anti-reflective properties, superhydrophobic properties, and durability.

[0047] It should be noted that "finger-dry state" means that when the coating is lightly touched with the back of a finger, there is no sticky residue and the coating shows no obvious deformation. Of course, in other embodiments, other coating methods that can apply shear force to promote liquid penetration into the pores can also be used, such as scraping, rolling, and extrusion coating, etc., which are not limited here.

[0048] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0049] 1. The coating provided in this embodiment of the invention constructs a three-dimensional network skeleton through the cross-linking reaction of the curing agent and polymer resin in the primer formulation. 5-10 parts of pore-forming agent are uniformly dispersed and locked inside the network. After curing, the pore-forming agent is washed away to form a micro-nano porous structure. At the same time, 2-5 parts of micro-nano-scale reinforcing filler are embedded in the cross-linking network to form a primary rough skeleton and significantly improve mechanical strength. The topcoat layer is composed of low surface energy nanoparticles and is embedded in the porous structure of the primer and then covered on top. This structure allows the topcoat nanoparticles to construct a secondary nano-rough structure to provide superhydrophobic and dihydrophobic properties, while their roots are anchored inside the primer skeleton rather than just adhering to the surface. This solves the defects of weak cohesion and easy peeling of the functional layer of traditional coatings. In this embodiment of the invention, the porous structure and the two-level rough structure work together to form an optical gradient refractive index layer, so that light transitions smoothly at the interface rather than abruptly, reducing scattering and achieving a transmittance higher than that of bare glass. At the same time, the cross-linking network and reinforcing filler work together to give the coating an excellent balance of mechanical strength, substrate adhesion and superhydrophobic and dihydrophobic properties.

[0050] 2. In this embodiment of the invention, a staged dispersion process is used to ensure that the micro-nano reinforced filler is uniformly and stably dispersed in the resin and avoids agglomeration. Pre-curing to the critical cross-linking "finger-dry state" locks the position of the pore-forming agent and filler while retaining the porosity. Immersion in a water bath at 30~40℃ can selectively elute the pore-forming agent within an optimized kinetic window to form open and interconnected micro-nano pores. Mixing fluorinated silane with modified silica nanosol achieves pre-regulation of the surface energy of nanoparticles and enhances the chemical bonding with the primer. The coating method of applying shear force forces the topcoat slurry to overcome air resistance and actively penetrate and fill into the deep porous structure. After the solvent evaporates, the nanoparticles are mechanically locked to the pore walls to form a three-dimensional tenon and mortise interlocking, ultimately obtaining a composite coating with high light transmittance, super hydrophobic properties and excellent durability. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0052] Figure 1 The reaction mechanism of perfluorosilanes in this embodiment of the invention;

[0053] Figure 2 This is a schematic diagram of the wear resistance test in an embodiment of the present invention;

[0054] Figure 3 This is a schematic diagram of the transparent superhydrophobic coating structure according to an embodiment of the present invention;

[0055] Figure 4 The contact angle of water on the surface of the transparent superhydrophobic coating prepared in Example 1 of this invention;

[0056] Figure 5 The contact angle of the transparent superhydrophobic coating surface prepared by hexadecane in Example 1 of this invention;

[0057] Figure 6 This is a screenshot from a video of a water droplet roll-off angle test at 2° obtained from the transparent superhydrophobic coating prepared in Example 1 of this invention.

[0058] Figure 7 This is a screenshot from a video of the 10° roll-off angle test of the transparent superhydrophobic coated n-hexadecane prepared in Example 2 of this invention.

[0059] Figure 8 Transmission spectra of bare glass and the transparent superhydrophobic glass prepared in Example 1 of this invention;

[0060] Figure 9 These are comparative photographs showing the state of water droplets on bare glass and the transparent superhydrophobic glass prepared in Example 1 of this invention. Figure 9 'a' corresponds to bare glass. Figure 9 b corresponds to transparent superhydrophobic glass. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0062] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0063] To address the core issues commonly found in existing transparent superhydrophobic coatings, such as weak topcoat adhesion, easy overall peeling, difficulty in balancing mechanical strength and superhydrophobic properties, and the inability to balance light transmittance and micro / nano roughness, this experiment aims to systematically verify the effectiveness of the "porous skeleton-interlocking" composite structure proposed in this invention. Specifically, by comparing key parameters such as the pore structure with and without pore-forming agents, different topcoat application methods (wiping and penetration vs. conventional spraying), and the scale matching effect of micro / nano filler particle size and pore-forming agent molecular weight, the study quantitatively evaluates their impact on interlayer adhesion (cross-cut test, grade 0 verification), mechanical strength (pencil hardness ≥4H), superhydrophobic properties (water contact angle >165°, oil contact angle ≥150°), and light transmittance (>95%). This reveals the essential role of the "mortise and tenon interlocking structure" in the synergistic enhancement mechanism of mechanical anchoring and chemical bonding, and establishes the optimal ratio range for the resin cross-linking network-pore-forming agent-reinforcing filler-topcoat nanoparticle system, providing sufficient experimental data support for the industrialization and patent protection of this technology. Example

[0064] This invention provides a method for preparing a durable, transparent, superhydrophobic coating with antireflective properties, comprising the following:

[0065] I. Substrate Preparation Process

[0066] S1. Pre-dispersion: Add 40-60 parts of polymer resin (including at least one of epoxy resin, acrylic resin, polyurethane resin, acrylic-polyurethane resin, silicone resin, and fluorocarbon resin), 5-10 parts of pore-forming agent (at least one of polyethylene glycol PEG-400, PEG-600, and PEG-1000), and 0.5-1 parts of dispersant (at least one of BYK-163, BYK-108, BYK-110, BYK-180, BYK-2155, and BYK-2152) to a high-speed disperser according to the formulation amount, and stir at 400-800 r / min. While stirring, slowly add 2-5 parts of micro / nano-scale reinforcing filler (at least one of fumed silica and precipitated silica, with a particle size of 15 nm-1300 nm and a refractive index of 1.4-1.7), adjust the speed to 1000-2500 r / min, and continue stirring for 10-30 min.

[0067] S2, Ultrasonic Dispersion: Transfer the mixture obtained in S1 to an ultrasonic disperser (power 400~600W), and perform intermittent ultrasonication (ultrasonication for 2~5s, pause for 1~2s) under ice water bath cooling, with a total duration of 5~30min. This process is beneficial for breaking up filler agglomerates, making the PEG phase micronized and achieving uniform distribution.

[0068] S3. Paint preparation: Add 1-50 parts of the curing agent and remaining diluent compatible with the resin (including at least one of water, xylene, n-butanol, ethyl acetate, butyl acetate, anhydrous ethanol, acetone, diglycidyl ether, 1,4-butanediol diglycidyl ether, and neopentyl glycol diglycidyl ether), and stir at 400-800 r / min for 3-8 min to obtain a uniform primer slurry with a viscosity range of 15-20 s (Ford Cup 4).

[0069] S4. Coating preparation and pre-curing: Apply the primer slurry to a dry, clean substrate surface using spraying, scraping, brushing, or roller coating methods. The wet film thickness is 20~100μm. Allow it to stand and level until it reaches the "finger-dry state" (when you lightly touch the coating with the back of your finger, there is no sticky residue and the coating does not show obvious deformation). The purpose of this step is to allow the resin to initially cross-link to achieve high mechanical properties, but not to fully cross-link to form a dense film. At this time, the pore-forming agent dissolves and forms open pores, which facilitates the penetration of the topcoat.

[0070] S5. Hole Formation: Immerse the pre-cured coating in a water bath containing deionized water at 30~40℃ and soak for 1.5~3h with stirring at 50~200 r / min. The warm water accelerates the dissolution and diffusion of PEG. After thorough washing, an interconnected open-pore structure is formed. After removal, rinse the surface with deionized water and anhydrous ethanol (or methanol, isopropanol) in sequence, and dry at room temperature for 0.5~2h to obtain the primer layer.

[0071] II. Topcoat Preparation

[0072] S6. According to the formula, 95-99% of low surface energy modified silica nanosol (solid content 2-30%, solvent is at least one of isopropanol, ethanol, and methanol, silica nanoparticle size 10-20nm) and 1-5% of fluorinated silane (at least one of perfluorodecyltriethoxysilane, perfluorooctyltriethoxysilane, trifluoropropyltrimethoxysilane, and perfluorooctylethyltrichlorosilane) are uniformly mixed and stirred at a speed of 800-2000r / min for 10-30 minutes to obtain the topcoat slurry.

[0073] III. Surface Layer Construction and Interlocking Structure Construction Methods

[0074] S7. Topcoat application: Apply topcoat to the substrate using a non-woven cloth, microfiber lint-free cloth, sponge, or other wiping material, saturating it with the topcoat. Apply 0.1~0.5 kgf / cm² of topcoat to the substrate.2 Vertical pressure is applied, and the coating is continuously rubbed 2-5 times in a unidirectional, circular, or reciprocating manner to obtain a super-hydrophobic topcoat. The construction principle includes: the shear force generated by rubbing effectively overcomes the cohesive force of the topcoat and the air resistance inside the pores, forcibly "pushing" the topcoat into the open pores of the underlying layer; the synergy of rubbing and capillary action allows the topcoat to be transported into the pores, and as the solvent evaporates, the low surface energy nanoparticles in the topcoat are "locked" in the pores and physically adsorbed onto the pore walls, creating a blurred, interpenetrating transition zone between the underlying and top layers, thus forming a robust three-dimensional interlocking structure for the entire coating system; the addition of perfluorosilanes to the topcoat allows for chemical bonding with the underlying resin and nanoparticle surface under the influence of water in the environment, further strengthening the aforementioned interlocking structure while reducing surface energy (structure reference). Figure 3 (As shown).

[0075] It should be noted that the preparation method of modified silica sol is as follows:

[0076] Add 2-50 parts of hydrophilic silica nanoparticles to 100-200 parts of isopropanol and / or ethanol and / or methanol, and ultrasonically disperse for 15-30 minutes. Then add 0.1-0.5 parts of fluorosilane (at least one of perfluorodecyltriethoxysilane, perfluorooctyltriethoxysilane, trifluoropropyltrimethoxysilane, and perfluorooctylethyltrichlorosilane), and stir in a water bath at 60℃-80℃ for 2-6 hours to obtain modified silica nanosol.

[0077] To better demonstrate the effectiveness of the embodiments of the present invention, the following experiments will be conducted for verification:

[0078] Example 1: This embodiment of the invention provides a method for preparing a durable transparent superhydrophobic coating with antireflective properties, comprising the following:

[0079] I. Primer Preparation

[0080] S1: Add 40g of silicone-modified polyurethane resin (T-30), 5g of PEG-400, 5g of PEG-600, and 0.7g of BYK-110 to a high-speed disperser and stir at 800 r / min. While stirring, slowly add 4g of fumed silica (REOLOSILQS-10) and 1g of ultrafine spherical silica (12500 mesh). Adjust the speed to 2500 r / min and continue stirring for 20 min.

[0081] S2: Transfer the mixture obtained in S1 to an ultrasonic disperser (400W power) and perform intermittent ultrasonication (2s ultrasonication, 1s pause) under ice water bath cooling for a total duration of 30min.

[0082] S3: Add 13g of T-30 matching curing agent, stir at 800 r / min for 5min, add anhydrous ethanol thinner, adjust the viscosity to 18s, and obtain a uniform primer.

[0083] II. Preparation of Topcoat

[0084] 2g of hydrophilic silica nanoparticles (Wacker N20) were added to 100g of anhydrous ethanol and ultrasonically dispersed for 30 minutes. Then, 0.1g of perfluorodecyltriethoxysilane was added, and the mixture was stirred in a 60℃ water bath for 4 hours to obtain modified silica nanosol. After cooling, 97g of the modified silica nanosol was mixed with 3g of perfluorooctyltriethoxysilane and stirred at 1500r / min for 15 minutes to obtain the topcoat.

[0085] III. Coating Preparation

[0086] S1: Spray the primer evenly onto the surface of a dry, clean ultra-clear glass substrate, with a wet film thickness of 20μm, and allow it to stand and level until it reaches the "finger-dry" state.

[0087] S2: Immerse the coating obtained in S1 in a water bath containing deionized water at 30°C, stir at 150 r / min to keep the water flowing, remove after soaking for 3 hours, rinse the surface with deionized water and anhydrous ethanol in sequence, and dry at room temperature for 1 hour to obtain a micro-nano porous bottom layer.

[0088] S3: Shake the topcoat well, saturate a white non-woven cloth with the topcoat, and apply 0.2 kgf / cm² of topcoat to the undercoat. 2 Apply vertical pressure and rub twice to obtain a transparent superhydrophobic composite coating TS-1.

[0089] Example 2: This embodiment of the invention provides a method for preparing a durable transparent superhydrophobic coating with antireflective properties, comprising the following:

[0090] I. Primer Preparation

[0091] S1: Add 40g of bisphenol A epoxy resin (Araldite® GY 282), 4g of PEG-400, 6g of PEG-1000, 0.5g of BYK-163 and an appropriate amount of diluent (diglycidyl ether) to a high-speed disperser and stir at 600 r / min. While stirring, slowly add 3g of fumed silica (AEROSIL 150) and 1g of silica glass powder (8000 mesh). Adjust the speed to 2000 r / min and continue stirring for 20 min.

[0092] S2: Transfer the mixture obtained in S1 to an ultrasonic disperser (400W power) and perform intermittent ultrasonication (2s ultrasonication, 1s pause) under ice water bath cooling, for a total duration of 15min.

[0093] S3: Add 3g of hardener (Ancamine 1618), stir at 500 r / min for 5 min, add diluent (diglycidyl ether) to adjust the viscosity to 15s, and obtain a uniform primer.

[0094] II. Preparation of Topcoat

[0095] 3g of hydrophilic silica nanoparticles (AEROSIL® A200) were added to 100g of isopropanol and ultrasonically dispersed for 15 minutes. Then, 0.2g of perfluorooctyltriethoxysilane was added, and the mixture was stirred in a 60℃ water bath for 5 hours to obtain modified silica nanosol. After cooling, 98g of the modified silica nanosol was mixed with 2g of perfluorodecyltriethoxysilane and stirred at 1000r / min for 15 minutes to obtain the topcoat.

[0096] III. Coating Preparation

[0097] S1: Spray the primer evenly onto the surface of a dry, clean ultra-clear glass substrate, with a wet film thickness of 40μm, and allow it to stand and level until it reaches the "finger-dry" state.

[0098] S2: Immerse the coating obtained in S1 in a water bath containing deionized water at 40°C, stir at 100 r / min to keep the water flowing, soak for 2 hours, remove and rinse the surface with deionized water and anhydrous ethanol in sequence, and dry at room temperature for 30 minutes to obtain a micro-nano porous bottom layer.

[0099] S3: Shake the topcoat well, saturate it with a white microfiber lint-free cloth, and apply 0.3 kgf / cm² of topcoat to the substrate. 2 By applying vertical pressure and unidirectional, continuous wiping three times, a transparent superhydrophobic composite coating TS-2 is obtained.

[0100] Example 3: This embodiment of the invention provides a method for preparing a durable transparent superhydrophobic coating with antireflective properties. The method includes the following:

[0101] I. Primer Preparation

[0102] S1: Add 50g of silicone-modified polyurethane resin (T-30), 4g of PEG-400, 4g of PEG-600, and 0.5g of BYK-110 to a high-speed disperser and stir at 600 r / min. While stirring, slowly add 2g of fumed silica (REOLOSILQS-10) and 2g of ultrafine spherical silica (12500 mesh). Adjust the speed to 1800 r / min and continue stirring for 20 min.

[0103] S2: Transfer the mixture obtained in S1 to an ultrasonic disperser (power 500W), and perform intermittent ultrasonication (3s ultrasonication, 1.5s pause) under ice water bath cooling, for a total duration of 15min.

[0104] S3: Add 20g of T-30 matching curing agent, stir at 600 r / min for 3min, add anhydrous ethanol thinner, adjust the viscosity to 20s, and obtain a uniform primer.

[0105] II. Preparation of Topcoat

[0106] 2g of hydrophilic silica nanoparticles (Wacker N20) were added to 100g of anhydrous ethanol and ultrasonically dispersed for 30 minutes. Then, 0.1g of perfluorodecyltriethoxysilane was added, and the mixture was stirred in a 60℃ water bath for 4 hours to obtain modified silica nanosol. After cooling, 99g of the modified silica nanosol was mixed with 1g of perfluorooctyltriethoxysilane and stirred at 800r / min for 30 minutes to obtain a topcoat.

[0107] III. Coating Preparation

[0108] S1: Spray the primer evenly onto the surface of a dry, clean ultra-clear glass substrate, with a wet film thickness of 50μm, and allow it to stand and level until it reaches the "finger-dry" state.

[0109] S2: Immerse the coating obtained in S1 in a water bath containing deionized water at 35°C, stir at 50 r / min to keep the water flowing, soak for 1.5 h, remove it, rinse the surface with deionized water and anhydrous ethanol in sequence, and dry at room temperature for 0.5 h to obtain a micro-nano porous bottom layer.

[0110] S3: Shake the topcoat well, saturate a white non-woven cloth with the topcoat, and apply 0.1 kgf / cm² of topcoat to the base coat. 2 Apply vertical pressure and rub back and forth 4 times to obtain a transparent superhydrophobic composite coating TS-3.

[0111] Example 4: This embodiment of the invention provides a method for preparing a durable transparent superhydrophobic coating with antireflective properties, comprising the following:

[0112] I. Primer Preparation

[0113] S1: Add 60g of silicone-modified polyurethane resin (T-30), 2.5g of PEG-400, 2.5g of PEG-1000, and 1g of BYK-180 to a high-speed disperser and stir at 400 r / min. While stirring, slowly add 1g of fumed silica (AEROSIL150) and 1g of ultrafine spherical silica (12500 mesh). Adjust the speed to 2500 r / min and continue stirring for 20 min.

[0114] S2: Transfer the mixture obtained in S1 to an ultrasonic disperser (600W power) and perform intermittent ultrasonication (5s ultrasonication, 2s pause) under ice water bath cooling, for a total duration of 5min.

[0115] S3: Add 13g of T-30 matching curing agent, stir at 400 r / min for 8min, add anhydrous ethanol thinner, adjust the viscosity to 18s, and obtain a uniform primer.

[0116] II. Preparation of Topcoat

[0117] 3g of hydrophilic silica nanoparticles (AEROSIL® A200) were added to 100g of isopropanol and ultrasonically dispersed for 15 minutes. Then, 0.2g of perfluorooctyltriethoxysilane was added, and the mixture was stirred in a 60℃ water bath for 5 hours to obtain modified silica nanosol. After cooling, 95g of the modified silica nanosol was mixed with 5g of perfluorooctyltriethoxysilane and stirred at 2000r / min for 10 minutes to obtain the topcoat.

[0118] III. Coating Preparation

[0119] S1: Spray the primer evenly onto the surface of a dry, clean ultra-clear glass substrate, with a wet film thickness of 100μm, and allow it to stand and level until it reaches the "finger-dry" state.

[0120] S2: Immerse the coating obtained in S1 in a water bath containing deionized water at 40°C, stir at 200 r / min to keep the water flowing, soak for 1.5 h, take it out, rinse the surface with deionized water and anhydrous ethanol in sequence, and dry at room temperature for 2 h to obtain a micro-nano porous bottom layer.

[0121] S3: Shake the topcoat well, saturate a white non-woven cloth with the topcoat, and apply 0.5 kgf / cm² of topcoat to the base coat. 2 Apply vertical pressure and rub back and forth 5 times to obtain a transparent superhydrophobic composite coating TS-4.

[0122] Comparative Example 1: A method for preparing a coating is provided, the difference from Example 1 being that the topcoat is applied by spraying, while the remaining steps remain unchanged, finally obtaining a composite coating TSC-1, wherein the spraying process of the topcoat is as follows:

[0123] 100g of fluorosilane-modified nano-silica sol (sol particle size 14nm, solvent is anhydrous ethanol) was mixed with 3g of perfluorooctyltriethoxysilane and stirred at 1500r / min for 15 minutes to obtain the topcoat.

[0124] Comparative Example 2: A method for preparing a coating is provided, which differs from Example 2 in that no pore-forming agent is added to the primer, while the other steps remain unchanged, and finally a composite coating TSC-2 is obtained.

[0125] Comparative Example 3: A method for preparing a coating is provided. The difference from Example 2 is that no micro / nano-scale reinforcing filler is added to the primer, while the other steps remain unchanged, and a composite coating TSC-3 is finally obtained.

[0126] Comparative Example 4: A method for preparing a coating is provided, which differs from Example 1 in that 6g of PEG-400 and 6g of PEG-600 are used, while the remaining steps remain unchanged, and finally a composite coating TSC-4 is obtained.

[0127] Comparative Example 5: A method for preparing a coating is provided, which differs from Example 1 in that 2g of PEG-400 and 2g of PEG-600 are used, while the remaining steps remain unchanged, and finally a composite coating TSC-5 is obtained.

[0128] Comparative Example 6: A method for preparing a coating is provided, which differs from Example 1 in that 1g of fumed silica (AEROSIL 150) and 0.5g of ultrafine spherical silica (12500 mesh) are slowly added while stirring, and the remaining steps remain unchanged, finally obtaining the composite coating TSC-6.

[0129] Comparative Example 7: A method for preparing a coating is provided, which differs from Example 1 in that 3g of fumed silica (AEROSIL 150) and 3g of ultrafine spherical silica (12500 mesh) are slowly added while stirring, and the remaining steps remain unchanged, finally obtaining the composite coating TSC-7.

[0130] Performance testing:

[0131] 1. Contact angle / roll-off angle

[0132] Instrument: dataphysics-OCA20

[0133] 2. Visible light transmittance and transmission spectrum

[0134] Instrument: Lambda 950. The visible light transmittance of glass coated with a transparent superhydrophobic coating was measured in both the examples and comparative studies.

[0135] 3. Adhesion (cross-cut test)

[0136] Refer to GB / T 9286 "Cross-cut test of paint and varnish film".

[0137] 4. Abrasion resistance

[0138] Abrasion resistance testing methods such as Figure 2 As shown:

[0139] Lay 1000-grit sandpaper face down on the coating surface, place a 100g weight on top of the sandpaper, and then slowly apply a horizontal pulling force to the sandpaper. After 100 cycles of friction, measure the water / oil contact angle of the coating. The test results are combined with... Figures 4-9 And as shown in Table 1 below:

[0140] Table 1

[0141]

[0142] According to the test results, the "mortise and tenon" interlocking structure constructed by the "wiping and coating penetration" process in this embodiment of the invention achieves a breakthrough from adhesion level 4 in Comparative Example 1 to adhesion level 0 in this embodiment. This breakthrough is not only due to the optimization of process parameters, but also to the utilization of 0.1~0.5 kgf / cm 2 The synergistic effect of vertical pressure and capillary action forces 10-20nm low surface energy modified silica nanoparticles to actively embed into the 15nm-1000nm porous framework through a deep anchoring mechanism. This enables the surface nanoparticles and the bottom pore walls to form a dual effect of physical locking and chemical bonding, thereby increasing the interlayer shear strength several times and endowing the coating with a pencil hardness of 4H or higher and a sandpaper abrasion resistance of more than 100 times. Figures 4-7 The displayed superhydrophobic performance data shows a water contact angle of ≥165° and a roll-off angle of 2°, and a hexadecane contact angle of ≥150° and a roll-off angle of 10°, compared with... Figure 8 The 95.1% transmittance in the mid-visible region (higher than the 92.4% of bare glass) demonstrates that the synergistic effect of the 15nm~1300nm primary rough structure constructed from fumed silica and precipitated silica, combined with the secondary rough structure formed by the topcoat nanoparticles, and the micro / nano porous structure formed after elution with PEG-400 / 600 / 1000 porogen, creates a gradient refractive index layer at the interface, effectively suppressing light scattering and achieving an anti-reflection effect. Compared with the failure mode of large-area peeling and a sharp drop in contact angle to hydrophilic level after friction in Comparative Example 2 (no pores), the open channels formed by 5~10% porogen in this invention are a necessary prerequisite for the mechanical interlocking of the topcoat functional units. The results show a stark contrast to Comparative Example 3 (without filler), which only achieved a B-level hardness and lost its function after wear resistance. This demonstrates that the 2-5% micro-nano reinforcing filler is not only a rough structural framework but also a key "stone" supporting the mechanical strength of the porous coating. It also demonstrates the significant effect of the step-by-step construction of the porous bottom layer and the embedded interlocking surface layer in the embodiments of this invention. This solves the industry pain points of existing technologies where mechanical strength and super-hydrophobic properties cannot be simultaneously achieved, and interlayer adhesion is weak. It provides an innovative solution with high hardness, high light transmittance, and durable super-hydrophobic properties for transparent self-cleaning fields such as architectural glass curtain walls, solar cell cover plates, automotive windshields, optical lenses, anti-fouling glasses, LED packaging, and flexible display devices.

[0143] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A durable, transparent, superhydrophobic coating with antireflective properties, characterized in that, It includes a primer layer and a topcoat layer, wherein the primer layer includes a porous structure, and the topcoat layer is configured to be embedded in the porous structure and cover the primer layer; The topcoat layer is applied by: using at least one of the following wiping materials—non-woven fabric, microfiber lint-free cloth, and sponge—to saturate the topcoat layer components, and then applying 0.1~0.5 kgf / cm² to the primer layer. 2 Apply pressure and wipe 2-5 times consecutively; The primer layer comprises a material prepared from the following raw materials in parts by weight: 40-60 parts polymer resin, 5-10 parts pore-forming agent, 2-5 parts micro / nano-scale reinforcing filler, 0.5-1 part dispersant, 1-50 parts curing agent, and 1-50 parts diluent; The curing agent can undergo a cross-linking reaction with the polymer resin to form a porous structure; The topcoat layer comprises a material prepared from modified silica nanosol and fluorinated silane, wherein the fluorinated silane accounts for 1-5% of the weight of the raw materials of the topcoat layer; The particle size of the micro-nano-scale reinforced filler is 15nm~1300nm, and the molecular weight of the porogen is 400~1300. The modified silica nanosol comprises silica nanoparticles and a solvent, wherein the solid content of the modified silica nanosol is 2-30%, and the particle size of the silica nanoparticles is 10-20 nm. The micro- and nano-scale reinforcing fillers in the primer layer are embedded in the cross-linked network to form a primary rough structure framework, which, together with the pores formed after the pore-forming agent is eluted and the silica nanoparticles in the topcoat layer, forms a secondary rough structure, synergistically generating an optical gradient refractive index layer.

2. The durable transparent superhydrophobic coating with antireflective properties according to claim 1, characterized in that, The polymer resin includes at least one of epoxy resin, acrylic resin, polyurethane resin, acrylic-polyurethane resin, silicone resin, and fluorocarbon resin; The porogen is selected from at least one of PEG-400, PEG-600, and PEG-1000; The micro-nano-scale reinforcing filler includes at least one of fumed silica and precipitated silica.

3. The durable transparent superhydrophobic coating with antireflective properties according to claim 2, characterized in that, The diluent includes at least one of water, xylene, n-butanol, ethyl acetate, butyl acetate, anhydrous ethanol, acetone, diglycidyl ether, 1,4-butanediol diglycidyl ether, and neopentyl glycol diglycidyl ether.

4. The durable transparent superhydrophobic coating with antireflective properties according to claim 1, characterized in that, The solvent includes at least one of isopropanol, ethanol, and methanol.

5. A durable transparent superhydrophobic coating with antireflective properties according to claim 4, characterized in that, The fluorinated silane includes at least one of perfluorodecyltriethoxysilane, perfluorooctyltriethoxysilane, trifluoropropyltrimethoxysilane, and perfluorooctylethyltrichlorosilane.

6. A method for preparing a durable transparent superhydrophobic coating with antireflective properties as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Stir the polymer resin, pore-forming agent, dispersant and part of the diluent, and add the micro-nano-scale reinforcing filler while stirring and continue stirring and dispersing; S2: Add curing agent and remaining diluent to the dispersed raw materials and continue dispersing to obtain primer slurry; S3: Apply the primer slurry to the substrate and then pre-cure it; S4: Immerse the pre-cured substrate with primer in deionized water at 30~40℃ to form a porous structure. Then clean and cure the porous structure to obtain the primer layer. S5: A topcoat slurry is obtained by mixing modified silica nanosol and fluorinated silane; S6: The topcoat slurry is applied over the primer layer, and after the topcoat slurry fills the porous structure and dries, a topcoat layer is formed, resulting in a double-hydrophobic coating.

7. The method for preparing a durable transparent superhydrophobic coating with antireflective properties according to claim 6, characterized in that, The wet film thickness after coating in S3 is 20~100μm, and the pre-curing includes allowing the wet film to stand and level until it reaches a "finger-dry" state; The curing described in S4 includes drying at room temperature for 0.5 to 2 hours.

Images