High-wear-resistance high-transparency super-hydrophobic nano coating and preparation method thereof

Abstract

The present application belongs to the technical field of super-hydrophobic coating, and particularly relates to a high-wear-resistance high-transparency super-hydrophobic nano coating and a preparation method thereof. In order to develop a super-hydrophobic coating material with high wear resistance and high transparency, the present application prepares a surface rough structure required by a super-hydrophobic coating through an organic-inorganic nano hybrid material, and prepares a coating surface with a single nano scale and a conical structure through a V-shaped nano pore template, and then chemically modifies the surface structure through a liquid-like molecule with low surface energy and low friction coefficient. After steps such as preparation of a coating, pretreatment of a template, preparation of a coating structure, and chemical modification of a coating surface, a super-hydrophobic nano coating is prepared. Through synergistic effects of organic-inorganic hybridization, nano conical geometry, and liquid-like surface chemistry, the wear resistance of the coating is effectively improved, and the coating has high transparency and super-hydrophobicity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of super-hydrophobic coating, and particularly relates to a high-wear-resistance high-transparency super-hydrophobic nano coating and a preparation method thereof. BACKGROUND

[0002] A super-hydrophobic surface refers to a surface with a water droplet contact angle greater than 150° and a rolling angle less than 10°, on which a water droplet can freely roll, so as to keep the surface dry and remove solid impurities and pollutants on the surface, and has a self-cleaning function. The super-repellent property of a water droplet on a super-hydrophobic surface usually depends on two key factors, i.e. a surface micro / nano structure and a low surface energy chemical. A water droplet is in a Cassie-Baxter state on a super-hydrophobic surface, and only contacts the top of the structure, forming a stable air layer between the structures. Due to its excellent water repellency, low adhesion and self-cleaning properties, super-hydrophobic materials have important application prospects in the fields of surface anti-fouling, anti-icing, high-efficiency heat exchange, drag reduction transportation and the like.

[0003] With the rapid increase in the outdoor application demand of light energy conversion devices (such as solar panels) and optical display devices (such as cameras, electronic display boards, street lamps, traffic lights, automobile windows and the like), super-hydrophobic coating materials will play a more important application value. In an outdoor scene, dust, rain, snow and the like covering the surface of a device will have a serious impact on the performance and display effect of the device, and a super-hydrophobic coating can effectively solve this problem, which requires that the coating material not only has super-hydrophobic self-cleaning properties and optical transparency, but also has good wear resistance, can withstand repeated wiping, and can meet the demand of actual application scenarios.

[0004] The reported coating is difficult to have super-hydrophobicity, high transparency and high mechanical wear resistance at the same time. On the one hand, super-hydrophobicity requires that the surface of the coating has a micro / nano-scale rough structure, and when the surface structure size is in the micron level or greater than the wavelength of light, light scattering and haze will be significantly increased, resulting in the decrease of the optical transparency of the material. In view of this problem, it can be known through Mie and Rayleigh light scattering theory analysis that the surface structure of the coating should be in the nanometer scale and the structure size should be less than 200 nm to realize super-hydrophobicity and high optical transparency at the same time. Although some nano-scale structured transparent super-hydrophobic coatings have been reported, these coating materials have a single nanometer scale surface structure, but they are fragile and difficult to resist mechanical wear, resulting in poor stability and durability of the coating. Mechanical wear not only destroys the surface structure, changes the surface chemical composition, and causes the loss of super-hydrophobicity, but also easily produces scratches, which affects the optical performance of the coating. This is a core problem that the super-hydrophobic coating faces in practical application. If a larger scale micron structure is introduced to improve the wear resistance, the transparency will be reduced and the haze will be increased. Therefore, how to design and prepare a super-hydrophobic coating material with high wear resistance and high transparency has been a technical problem to be solved in the coating research field. SUMMARY

[0005] In view of the problem that the existing super-hydrophobic coating technology is difficult to realize super-hydrophobicity, high optical transparency and high mechanical wear resistance at the same time, the application provides a preparation method of a high-wear-resistance high-transparency super-hydrophobic nano coating, which realizes high wear resistance of the nano coating through the synergistic effect of organic-inorganic nano hybridization, nano conical geometric structure and liquid-like molecule modification, and simultaneously endows the coating with super-hydrophobicity and high transparency.

[0006] In order to achieve the above purpose, the application is realized by the following technical scheme:

[0007] The application provides a preparation method of a high-wear-resistance high-transparency super-hydrophobic nano coating, comprising the following steps:

[0008] S1, preparation of coating: mixing a liquid organic-inorganic hybrid molecule and a photoinitiator to prepare a light-curable liquid coating;

[0009] S2, template pretreatment: chemically modifying the nano conical hole template with a release agent to obtain a template that is easy to release;

[0010] S3, coating structure preparation: the liquid coating of step S1 is dropped onto the surface of the template of step S2, the target substrate is covered, pressure is applied to make the liquid coating evenly spread between the template and the substrate, and enter the nanopores of the template, then it is cured by ultraviolet light irradiation, and the cured coating attached to the surface of the substrate is peeled off from the template, and after secondary curing, an organic-inorganic hybrid coating with uniform nano-cone array structure is prepared;

[0011] S4, coating surface modification: the coating obtained in step S3 is first subjected to plasma treatment, and then the surface structure is chemically modified with low surface energy and low friction coefficient liquid-like molecules to obtain a super-hydrophobic coating with high wear resistance and high transparency.

[0012] In one embodiment, in step S1, the liquid organic-inorganic hybrid molecules include cage-shaped or ladder-shaped polyhedral oligomeric silsesquioxane (POSS). POSS consists of an inorganic core composed of Si-O alternating silicon-oxygen skeleton, and organic molecular chains with reactive groups connected at its eight corners. In addition, other organic-inorganic hybrid systems are also included, and the organic phase includes but is not limited to epoxy resin, acrylic resin, etc., and the inorganic phase includes but is not limited to silica, titanium dioxide, zirconium oxide, etc. nanoparticles (particle size below 300 nm).

[0013] In one embodiment, in step S4, the low surface energy and low friction coefficient liquid-like molecules include linear perfluoropolyether (PFPE) and polydimethylsiloxane (PDMS) liquid-like molecules with a molecular weight of 1000-10000 g / mol.

[0014] Firstly, the coating prepared by the method of the present application has an organic-inorganic hybrid system as the bulk material, which contains inorganic and organic nanophases, and the organic phase is an organic molecular chain with reactive groups. Cross-linking is carried out through the reaction between the reactive groups on the organic chain to form an organic-inorganic nanohybrid coating material. Since the organic-inorganic nanohybrid material has both the hardness of glass and the flexibility of polymer, the nanostructure prepared by using the organic-inorganic nanohybrid material can effectively strengthen the mechanical stability of the nanostructured surface: on the one hand, the coating material has very high hardness and can resist wear; on the other hand, the coating material can make the nanostructure have good toughness and will not be easily broken under the action of shear force.

[0015] Secondly, the surface geometry of the coating prepared by the method is a single nano-scale conical structure, the nano-conical structure is integrated with the bottom coating material, and is arranged in a close hexagonal array, and the structure size and period are smaller than the wavelength of visible light. The advantages of the geometric structure design include the following two aspects: on the one hand, compared with the nano-columnar structured coating surface reported, the nano-conical structure with the same bottom diameter can effectively solve the problem of root stress concentration of the nano-structure in the friction and wear process, avoid the structure from breaking from the root, and thus better mechanical stability and wear resistance are achieved. The nano-conical geometry can further optimize the wear resistance of the coating on the basis of the organic-inorganic hybrid material; on the other hand, compared with the traditional nano-columnar structured coating surface, the nano-conical structured coating surface is a gradually changing mixed medium layer composed of solid conical structure and air, the effective light refraction (n e ) is between the light refraction (n a ) of air and the light refraction (n s ) of solid, and gradually increases from air to solid, effectively avoiding the reflection of light on the coating surface caused by large refractive index mutation, so that the nano-conical structure has better antireflection and transmittance effect.

[0016] Finally, the liquid-like molecules with low surface energy and low friction coefficient are used for coating surface structure modification, the linear PFPE and PDMS molecules have a very low glass transition temperature (T g <-100℃), the PFPE and PDMS molecule brushes grafted on the solid surface are highly dynamic and flexible, have liquid-like properties, and water droplets and solids can easily slide on the modified surface, showing high sliding and low sticking properties. The advantages of using the liquid-like molecule layer modification are as follows: on the one hand, the PFPE and PDMS molecule brush modification film can reduce the friction coefficient of the coating surface, reduce the friction force on the nano-conical structure in the shearing and wear process, and maintain better mechanical stability. Moreover, the liquid-like molecule layer modification further improves the wear resistance of the coating on the basis of the organic-inorganic hybrid and conical geometry; on the other hand, for the hydrophilic nano-conical structure material, the PFPE and PDMS molecule brush modification film can reduce the surface energy of the coating to achieve super-hydrophobic effect.

[0017] As can be seen from the above, the organic-inorganic nano-hybrid, nano-conical geometry and liquid-like molecule modification are synergistically used to realize the high wear resistance of the nano-coating, and at the same time, the super-hydrophobicity and high transparency of the coating are also achieved.

[0018] Preferably, in one embodiment, the liquid organic-inorganic hybrid molecule is an epoxy cyclohexane ethyl polyhedral silsesquioxane or glycidyl ether oxypropyl polyhedral silsesquioxane.

[0019] In one embodiment, the photo-initiator in step S1 is a cationic initiator, including diaryliodonium salts, triarylsulfonium salts, alkylsulfonium salts, iron arene salts.

[0020] In one embodiment, the photo-initiator is preferably triarylsulfonium hexafluoroantimonate.

[0021] In one embodiment, the mass content of the photo-initiator in the liquid coating in step S1 is 1%-5%.

[0022] In one embodiment, in step S1, a certain amount of photo-initiator is added to the liquid organic-inorganic hybrid molecule when the coating is prepared, and it is mixed uniformly by stirring. The prepared coating does not contain any solvent and is in a flowing liquid state. The role of adding photo-initiator in the organic-inorganic molecule coating is to initiate the ring-opening reaction between the reactive epoxy groups on the organic chain under ultraviolet light, so as to cause the coating to crosslink and solidify.

[0023] In the organic-inorganic hybrid coating of step S2, the size and period (the distance between the centers of the V-shaped structures) of the nano-cone (V-shaped) array structure are both less than 200 nm.

[0024] The nano-cone array structure parameters meet two conditions: first, the size and period of the nano-cone structure are less than the theoretical threshold required for high optical transparency, i.e., less than 200 nm based on the Mie scattering and Rayleigh scattering theories, so as to effectively reduce light scattering and haze; second, the solid-liquid contact area ratio when the top of the structure is in contact with a liquid is less than the theoretical threshold required for superhydrophobicity. Based on the Cassie-Baxter model equation cosθ = f cosθ0-(1-f), θ is the apparent contact angle of the coating, θ0 is the intrinsic contact angle of the material, and f is the solid-liquid contact area ratio, wherein f = πd 2 / (2√3l 2 ), d is the diameter of the top of the structure, and l is the period of the structure. It can be seen that if the surface chemical modifier has an intrinsic contact angle θ0 > 100°, in order to make θ satisfy θ > 150°, the solid-liquid contact area ratio f must be less than 16.2%, and d / l must be less than 0.42.

[0025] In one embodiment, the nano-cone hole template in step S2 has an array arrangement, a bottom hole diameter of 10-80 nm, a top hole diameter of 50-200 nm, and a period of 50-200 nm; the nano-cone hole template includes a cone (V-shaped) hole anodic aluminum oxide template (AAO) and a cone (V-shaped) hole resin template obtained by photolithography and replication.

[0026] In order to obtain the nano-cone structure array coating surface, the application adopts a template imprinting technology based on light curing. The template used is a V-shaped nano-pore template, which needs to be pretreated and modified before use to make the cured coating more easily demoulded. The specific operation of coating preparation is as follows: the above-mentioned configured coating is dropped onto the template surface, the target substrate is covered, a certain pressure is applied to make the liquid coating spread between the template and the substrate and enter the V-shaped pores of the template. The coating material is crosslinked and cured by ultraviolet light irradiation, and the cured coating is separated from the template surface by physical peeling, the coating is attached to the surface of the substrate, and the coating bottom support layer and the surface structure are integrally formed. The coating is secondarily cured by heating to obtain an organic-inorganic hybrid nano-cone structured coating. The template can be opaque, such as an AAO template, and the substrate requires a transparent substrate, and the ultraviolet light irradiation and curing are performed from the transparent substrate surface; the template can also be transparent, such as a transparent resin template obtained by photolithography and replication, and the transparency of the substrate is not required, and the ultraviolet light irradiation and curing can be performed from the transparent template surface.

[0027] In one embodiment, the demoulding agent in step S2 is a low surface energy chemical modification molecule, including perfluoropolyether silane (PFPE, molecular weight 1000-10000 g / mol), perfluoroalkyl silane, alkyl silane and other alkyl surfactants (carbon atom number 3-50).

[0028] Preferably, in one embodiment, the demoulding agent is perfluoropolyether silane (PFPE). The specific operation of template pretreatment and modification is as follows: the template is placed in a plasma machine for treatment, and then the template treated by plasma is immersed in a perfluoropolyether silane solution with a concentration of 0.1%-1% for 1 min, and then taken out and heated at 60-150°C for 0.5-1 h.

[0029] In one embodiment, the ultraviolet light curing light source in step S3 includes ultraviolet light LED lamp and high pressure mercury lamp, and the curing time is 3 s-10 min; the secondary curing is thermal curing, the thermal curing temperature is 60°C-150°C, the humidity is 60%-100%, and the time is 0.5-3 h.

[0030] In one embodiment, the specific operation of modifying the PFPE type liquid molecular brush in step S4 is as follows: the coating treated by plasma is placed in a perfluoropolyether silane solution with a concentration of 0.1%-1%, immersed for 1 min, taken out, and heated at 60-150°C for 0.5-1 h. The specific operation of modifying the PDMS type liquid molecular brush is as follows: the coating treated by plasma is placed in pure polydimethylsiloxane liquid and heated at 80-120°C for 12-36 h.

[0031] Preferably, in one embodiment, in step S4, the PFPE-based liquid molecules are trimethoxysilane, triethoxysilane, trichlorosilane-terminated linear perfluoropolyether, with a molecular weight of 1000-10000 g / mol; the PDMS-based liquid molecules are methyl-, hydroxyl-, amino-, vinyl-, or epoxy-terminated linear polydimethylsiloxane, with a molecular weight of 1000-10000 g / mol.

[0032] In one embodiment, in step S4, the plasma treatment gas source is oxygen or air, the treatment intensity is 10-50 W, and the treatment time is 1-10 min. The coating surface is subjected to plasma treatment before being chemically modified by the liquid-like molecules, so that the surface is provided with reactive hydroxyl groups.

[0033] The application also provides a high-wear-resistance high-transparency super-hydrophobic nanocoating prepared by the above method.

[0034] The wear-resistant transparent super-hydrophobic nanocoating prepared by the method of the application comprises an organic-inorganic hybrid bulk material, a nano-cone array structure, and a liquid-like molecule modification layer. The wear resistance of the coating is improved through the synergistic effect of the organic-inorganic hybridization, the nano-cone geometric structure, and the liquid-like surface chemistry, and the coating has high transparency and super-hydrophobicity. The surface of the prepared coating has super-hydrophobicity and self-cleaning performance, the contact angle of water droplets on the surface of the coating is greater than 160°, and the rolling angle is less than 5°. At the same time, the super-hydrophobic coating has high optical transparency, has antireflection and anti-fogging effects, has a visible light transmittance of 104%, and a haze of less than 1.0%. In addition, the surface of the transparent super-hydrophobic coating has strong structural stability and mechanical wear resistance, and can still maintain super-hydrophobicity and high transparency after 5000 times of wear.

[0035] Compared with the prior art, the application has the following advantages:

[0036] The application discloses a preparation method of a high-wear-resistance high-transparency super-hydrophobic nano coating.

[0037] (1) The coating preparation process is simple and controllable, and is suitable for various flat substrates. The coating is prepared on a transparent flexible film substrate with adhesive, and a super-hydrophobic coating film is obtained, which can be applied to various equipment surfaces and realizes wider application.

[0038] (2) The coating surface is an organic-inorganic hybrid nano conical structure modified by liquid-like molecules, which is arranged regularly and has uniform structure size. The coating has super-hydrophobicity, high transparency and high wear resistance, and meets the actual application requirements.

[0039] (3) The prepared coating has strong adhesion and excellent mechanical wear resistance. Under a pressure of 60 MPa, the coating can withstand friction of a dust-free paper for more than 5000 times.

[0040] (4) The prepared coating has excellent super-hydrophobicity. The contact angle of a water drop is greater than 160°, and the rolling angle is less than 5°, so that the self-cleaning effect can be realized.

[0041] (5) The prepared coating has excellent optical transparency, has an antireflection and anti-reflection effect, and has a visible light transmittance of 104% and a haze of less than 1.0%. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 FIG. 1 is a structural schematic diagram of a high-wear-resistance high-transparency super-hydrophobic nano coating material.

[0043] Figure 2 FIG. 2 is a molecular structure of a bulk material and a surface modifier used in examples 1-3, wherein (a) is a POSS organic-inorganic hybrid molecule, (b) is a PDMS liquid-like molecule, and (c) is a PFPE liquid-like molecule.

[0044] Figure 3 SEM image of V-shaped pore AAO template;

[0045] Figure 4 SEM image of the obtained nano-cone structured coating;

[0046] Figure 5 Effect picture showing the transparency, flexibility and super-hydrophobicity of the obtained coating material;

[0047] Figure 6 Light transmittance curve of the obtained coating material under different wavelengths of light;

[0048] Figure 7 Wear resistance of the obtained coating material, (a) picture of contact angle of water droplets before abrasion, (b) picture of friction and abrasion equipment, (c) picture of contact angle of water droplets after abrasion. DETAILED DESCRIPTION

[0049] The specific embodiments of the present application are further described below. It should be noted that the description of these embodiments is intended for purposes of illustration, and is not intended to limit the application. Furthermore, the features of the various embodiments of the present application described below can be combined with each other, unless the features are mutually exclusive.

[0050] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0051] Example 1: Preparation method of a high-wear-resistance high-transparency super-hydrophobic nano-coating

[0052] The preparation method of the high-wear-resistance high-transparency super-hydrophobic nano-coating comprises the following steps:

[0053] S1, preparation of the coating: a triarylsulfonium hexafluoroantimonate mixture photoinitiator is added to a caged glycidyl ether oxypropyl polyhedral oligomeric silsesquioxane (POSS) organic-inorganic hybrid molecular liquid raw material (the molecular formula of the caged POSS organic-inorganic hybrid molecule is shown in Figure 2 a, which is purchased from Guangzhou Yixin Technology Co., Ltd., product model POSS101, CAS number 68611-45-0) to obtain a transparent liquid coating without solvent, with the mass content of the photoinitiator in the coating being 2.5%, and the mixture being fully stirred for 2 h to make it uniformly mixed;

[0054] S2, template pretreatment: a V-shaped nanopore AAO template (purchased from Shenzhen Topology Membrane Technology Co., Ltd., and subjected to scanning electron microscope detection, with the scanning electron microscope being as shown in Figure 3The AAO template surface has a uniform V-shaped pore structure, with a top pore size of 125 nm, a bottom pore size of 40 nm, a pitch of 125 nm, and a pore depth of 250 nm, as shown in FIG. 1. The AAO template was placed in a plasma machine for processing, with an oxygen gas source and a power of 50 W, and a processing time of 5 min. The processed AAO template was placed in a 0.5% perfluoropolyether silane (PFPE, purchased from Daikin (Japan), model OPTOOL UD509, molecular weight 4000-8000 g / mol, CAS No. 870998-78-0) solution (the molecular formula of the PFPE liquid molecule is as shown in FIG. 2), immersed for 1 min, and then placed in an oven at 130°C for heating and reaction for 30 min to obtain a perfluoropolyether-modified AAO template. Figure 2 c), and then placed in an oven at 80°C for heating and reaction for 1 h to obtain a nano-coating material with a conical structure. The composition and structure of the coating material are as shown in FIG. 3. The coating material includes an organic-inorganic hybrid bulk material, a nano-conical array structure, and a liquid-like molecule modification layer, and is an organic-inorganic hybrid nano-conical structure superhydrophobic coating material modified by a perfluoropolyether liquid-like molecule layer.

[0055] S3, coating structure preparation: The coating of step S1 was dropped onto the template surface of step S2, a transparent PET substrate was covered, a certain pressure was applied to evenly spread the liquid coating between the AAO template and the PET substrate, and the liquid coating entered the AAO template nanopores. After curing of the coating by irradiation under a high-pressure mercury lamp for 6 min, the solidified coating attached to the substrate surface was peeled off from the AAO template. The coating material was then placed in an oven for secondary curing, with a temperature of 80°C, a humidity of 80%, and a heating time of 2 h, to obtain a transparent organic-inorganic hybrid coating material with a uniform nano-conical array structure.

[0056] S4, coating surface modification: The coating material obtained in step S3 was first subjected to plasma treatment, with an oxygen gas source and a power of 15 W, and a processing time of 2 min. The treated coating material was then placed in a 0.5% perfluoropolyether silane (PFPE, purchased from Daikin (Japan), model OPTOOL UD509, molecular weight 4000-8000 g / mol, CAS No. 870998-78-0) solution, immersed for 1 min, and then placed in an oven at 80°C for heating and reaction for 1 h to obtain a nano-coating material with a conical structure. The composition and structure of the coating material are as shown in FIG. 3. The coating material includes an organic-inorganic hybrid bulk material, a nano-conical array structure, and a liquid-like molecule modification layer, and is an organic-inorganic hybrid nano-conical structure superhydrophobic coating material modified by a perfluoropolyether liquid-like molecule layer. Figure 1

[0057] The surface of the prepared nano-coating was detected by scanning electron microscopy, and the scanning electron microscope is as shown in FIG. 4. The surface structure of the prepared coating is uniformly arranged in a nano-conical structure array, with a structure size and a period of less than 200 nm. Figure 4

[0058] ​​At the same time, the transparency, flexibility and wettability of the nanocoating surface were tested. Transparency was measured by UV-visible-near-infrared spectrophotometer (PerkinElmer (USA), model Lambda 950) to measure light transmittance and haze value; wettability was measured by contact angle meter (Krüss DSA100) using sessile drop method to measure water drop contact angle. All results were captured by camera (Canon (Japan) EOS80D). Optical photos of the coating material and the wetting state of water droplets on the coating surface are shown in Figure 2. Figure 5 As shown. The prepared coating material has good optical transparency, and the background pattern is not disturbed by the naked eye. The coating material has good flexibility and can be bent into a U shape without cracking and can maintain super hydrophobicity. The transmittance of the obtained nano coating to visible light is tested, and the curve of light transmittance changing with light wavelength is shown as follows. Figure 6 As shown, the prepared nanocoating has high visible light transmittance, having anti-reflection and anti-transmittance effects. After deducting the light transmittance of the PET substrate, the light transmittance of the coating can reach 104%, and the haze is about 0.3%, which is less than 1%. Generally speaking, high-resolution imaging / display devices require transparency greater than 90% and haze less than 1%, while general devices require transparency greater than 80% and haze less than 3% (Hwan S, Moon, Hyunjin, et al. Low-haze, annealing-free, very long Ag nanowire synthesis and its application in a flexible transparent touch panel[J].[2023-06-07].;Weisheng Y, Liang J, Wei L, et al. Morphology control for tunable optical properties of cellulose nanofibrils films[J].Cellulose,2018,25:5909-5918.DOI:10.1007 / s10570-018-1974-1.). Therefore, the prepared nanocoating can meet the practical application requirements of optical display screens, automotive glass, surveillance cameras and other equipment.

[0059] Finally, the wear resistance of the obtained nanocoating was tested, and the contact angle of the water droplet on the coating surface before and after wear was as follows: Figure 7The results show that the contact angle of water droplets on the surface of the coating before abrasion is 167°, the roll angle is 3°; after 5000 times of abrasion on the dust-free paper under the pressure of 60KPa (500g gravity), the contact angle of water droplets on the surface of the coating is 159°, the roll angle is 9°, and the super-hydrophobicity and transparency can still be maintained, which indicates that the prepared transparent super-hydrophobic coating has good mechanical stability and abrasion resistance.

[0060] Example 2 A method for preparing a high-abrasion-resistant and high-transparency super-hydrophobic nano coating

[0061] The method for preparing the high-abrasion-resistant and high-transparency super-hydrophobic nano coating is the same as that in Example 1, except that the liquid raw material in step S1 is replaced by a cage-shaped octa-epoxy-cyclohexane ethyl polysilsesquioxane organic-inorganic hybrid molecule (purchased from Guangzhou Yixin Technology Co., Ltd., product model POSS1010, CAS No. 187333-74-0).

[0062] The super-hydrophobicity, transparency and abrasion resistance of the prepared nano coating material are equivalent to those in Example 1.

[0063] Example 3 A method for preparing a high-abrasion-resistant and high-transparency super-hydrophobic nano coating

[0064] The method for preparing the high-abrasion-resistant and high-transparency super-hydrophobic nano coating is the same as that in Example 1, except that in step S4, after the plasma treatment of the coating material, the coating material is placed in pure polydimethylsiloxane (PDMS) liquid (CAS No. 512-56-1, the molecular formula of the PDMS liquid molecule is as shown in Figure 2 b) and placed in an oven at 100°C for 24h of heating reaction.

[0065] The super-hydrophobicity, transparency and abrasion resistance of the prepared nano coating material are equivalent to those in Example 1.

[0066] Comparative Example 1 A method for preparing a high-abrasion-resistant and high-transparency super-hydrophobic nano coating

[0067] The method for preparing the high-abrasion-resistant and high-transparency super-hydrophobic nano coating is the same as that in Example 1, except that in step S4, after the plasma treatment of the coating material, the treated coating material and 50μL of perfluorooctyltrichlorosilane (CAS No. 78560-45-9) are placed in a vacuum dryer for 2h of vapor deposition reaction, and then taken out and placed in an oven at 80°C for 1h of heating.

[0068] Comparative Example 2 A method for preparing a high-abrasion-resistant and high-transparency super-hydrophobic nano coating

[0069] The preparation method of the high wear-resistant high-transparency superhydrophobic nano-coating is the same as that of Embodiment 1, except that in step S24, the used template is a U-shaped nanopore AAO template (purchased from Shenzhen Topology Membrane Technology Co., Ltd.) with a top pore diameter of 60 nm and a pore depth of 150 nm.

[0070] For comparison of the wear resistance of the transparent superhydrophobic coatings prepared in Comparative Examples 1 and 2, and for example, the transparent superhydrophobic coating of Embodiment 1, the detection method is as follows: the prepared coating sample is flatly pasted on a glass sheet and placed on the device table of an abrasion tester (linear abrasion tester Taber (USA), Model 5750) as shown in FIG. b. Dust-free paper is attached to the bottom of the grinding head as the grinding head material, the grinding head diameter is 1 cm, the grinding head is pressed on the surface of the coating sample, the load gravity is 500 g, the device is started, and the back-and-forth friction is performed at a speed of 30 cycles / min. The static contact angle (5 μL water droplet) and the rolling angle (20 μL water droplet) of the water droplet on the surface of the coating sample before and after abrasion are tested by a contact angle instrument. The detection results are shown in Tables 1 and 2. Figure 7

[0071] Comparative Example 1 uses a non-liquid-like molecule modifier to prepare a transparent superhydrophobic nano-coating. As can be seen from the friction and wear test results in Tables 1 and 2, compared with Embodiment 1, the wear resistance of the transparent superhydrophobic coating material prepared in Comparative Example 1 is poor. Before abrasion, the contact angle of the water droplet on the surface of the coating is 170°, and the rolling angle is 2°, which has superhydrophobicity. After 2000 times of abrasion by the dust-free paper under a pressure of 60 KPa (500 g gravity), the contact angle of the water droplet on the surface of the coating is reduced to below 150°, and the rolling angle is increased to above 15°, which no longer has superhydrophobicity. It is indicated that the liquid-like molecule layer modification can further improve the wear resistance of the nano-coating. Comparative Example 2 uses a U-shaped nanopore template to prepare a transparent superhydrophobic coating with a nano-pillar structure. Compared with Embodiment 1, the wear resistance of the transparent superhydrophobic coating material with a nano-pillar structure prepared in Comparative Example 2 is poorer. Before abrasion, the contact angle of the water droplet on the surface of the coating is 165°, and the rolling angle is 5°, which has superhydrophobicity. After only 100 times of abrasion by the dust-free paper under a pressure of 60 KPa (500 g gravity), the contact angle of the water droplet on the surface of the coating is reduced to 145°, and the rolling angle is increased to 75°, which no longer has superhydrophobicity. In addition, the visible light transmittance of the nano-pillar structure coating is 102%, which is lower than that of the nano-cone structure coating (104%). It is indicated that the nano-cone geometric structure can further improve the wear resistance of the nano-coating, and at the same time has a better antireflection effect.

[0072] ​From the above comparison results, the high wear-resistant high-transparency super-hydrophobic nano coating proposed in the application is the result of synergistic effect of three aspects of organic-inorganic hybridization, nano conical geometry and liquid-like molecule modification. That is, the wear resistance of the coating is improved through the synergistic effect of the three aspects of organic-inorganic hybridization, nano conical geometry and liquid-like surface chemistry, and the coating has high transparency and super-hydrophobicity at the same time.

[0073] Table 1 Change of static contact angle of water droplets with friction frequency

[0074]

[0075]

[0076] Table 2 Change of rolling angle of water droplets with friction frequency

[0077]

[0078] The embodiments of the application are described in detail above, but the application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the application, and still fall within the protection scope of the application.

Claims

1. A method for preparing a highly wear-resistant and highly transparent super-hydrophobic nano-coating, characterized in that: It is formed by the following steps: S1. Preparation of coating: mixing liquid organic-inorganic hybrid molecules and a photoinitiator to prepare a photocurable liquid coating; the liquid organic-inorganic hybrid molecules are cage-shaped or ladder-shaped polysilsesquioxanes; S2. Template pretreatment: Chemically modifying the nano-conical pore template with a release agent to obtain an easily demoldable template; the release agent is a low-surface-energy chemical modification molecule selected from perfluoropolyether silane; the nano-conical pore template has pores arranged in an array, with a bottom pore diameter of 10-80 nm, a top pore diameter of 50-200 nm, and a period of 50-200 nm; the nano-conical pore template includes a conical pore anodized aluminum template and a conical pore resin template obtained by photolithography and replication; The specific operation of template pretreatment modification is as follows: placing the template in a plasma machine for treatment, then dipping the plasma-treated template in a 0.1%-1% perfluoropolyether silane solution for 1 minute, taking it out and heating it at 60-150° C. for reaction for 0.5-1 hour; S3. Preparation of coating structure: The liquid coating prepared in step S1 is added dropwise to the surface of the template pretreated in step S2, covering the target substrate. Pressure is applied to evenly spread the liquid coating between the template and the substrate and enter the nanopores of the template. The liquid coating is then cured by ultraviolet light irradiation. The cured coating attached to the substrate surface is peeled off from the template. After secondary curing, an organic-inorganic hybrid coating with a uniform nanocone array structure is obtained. S4. Coating surface modification: The coating obtained in step S3 is first subjected to plasma treatment, and then its surface structure is chemically modified with liquid-like molecules having low surface energy and low friction coefficient to obtain a highly wear-resistant and highly transparent superhydrophobic coating; the liquid-like molecules having low surface energy and low friction coefficient are selected from linear perfluoropolyether and polydimethylsiloxane liquid molecules, and have a molecular weight of 1000-10000 g / mol; In the organic-inorganic hybrid coating of step S2, the size and period of the nanocone array structure are both less than 200 nm; The haze of the highly wear-resistant and highly transparent super-hydrophobic nano-coating prepared according to steps S1-S4 is less than 1.0%.

2. The method for preparing a highly wear-resistant and highly transparent super-hydrophobic nano-coating according to claim 1, wherein: In step S1, the photoinitiator is a cationic initiator, including diaryliodonium salts, triarylsulfonium salts, alkylsulfonium salts, and iron arene salts; the mass content of the photoinitiator in the liquid coating is 1%-5%.

3. The method for preparing a highly wear-resistant and highly transparent super-hydrophobic nano-coating according to claim 1, wherein: In step S3, the light source for UV curing includes a UV LED lamp and a high-pressure mercury lamp, and the curing time is 3 s-10 min; the secondary curing is thermal curing, and the thermal curing temperature is 60°C-150°C, the humidity is 60%-100%, and the time is 0.5-3 h.

4. The method for preparing a highly wear-resistant and highly transparent super-hydrophobic nano-coating according to claim 1, wherein: In step S4, the gas source for the plasma treatment is oxygen or air, the treatment intensity is 10 W-50 W, and the treatment time is 1-10 min.

5. A highly wear-resistant and highly transparent super-hydrophobic nanocoating prepared by the preparation method according to any one of claims 1 to 4.

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