A wear-resistant transparent flexible super-hydrophobic coating and a preparation method thereof

Abstract

The application provides a wear-resistant transparent flexible fluorine-free super-hydrophobic composite coating and a preparation method thereof. The preparation method comprises the following steps: mixing and reacting hydroxyl-terminated polydimethylsiloxane, gamma-aminopropyl triethoxysilane and dibutyl tin dilaurate to obtain a modified precursor solution, adding swelled epoxy resin into the modified precursor solution, and obtaining a siloxane modified epoxy resin after heating reaction; dispersing nano-silicon dioxide in an ethyl acetate solution to form a SiO2 suspension; uniformly mixing the modified epoxy resin and the SiO2 suspension, adding polyether amine as a curing agent, and stirring and mixing, and then adopting an air spraying mode to build an epoxy resin / hydroxyl-terminated polydimethylsiloxane / nano-silicon dioxide super-hydrophobic coating on a substrate. The preparation method can prepare a super-hydrophobic coating with excellent transparency and flexibility, good adhesion and wear resistance, and has a wide application prospect in the fields of wearable electronic devices and optoelectronic devices.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material surface coating, in particular to a kind of wear-resistant transparent flexible super-hydrophobic coating and preparation method thereof. BACKGROUND

[0002] Wear-resistant transparent super-hydrophobic coating has great application value in the field of flexible electronic devices and optoelectronic devices, such as wearable devices such as fitness bands and smart clothing, and optoelectronic devices such as flexible touch screens and photovoltaic solar cells. However, on the one hand, the surface of the coating must have high roughness to obtain high contact angle. The increase of roughness will reduce the transparency due to light scattering. In order to balance the transparency and super-hydrophobicity, a suitable roughness (less than 100 nm) needs to be selected. On the other hand, the flexibility and wear resistance of the transparent coating are in a competitive relationship. Materials with soft and stretchable molecular chains generally have low mechanical strength and are easily damaged by friction or cutting force; materials with high strength and hardness are generally rigid and have poor flexibility.

[0003] Chinese patent application No. 201310344505.5 proposes a method for preparing a water-based epoxy resin and a super-amphiphobic coating thereof. The method introduces different monomers into two specific positions of the water-based epoxy resin molecules, thereby achieving super-amphiphobic effect. However, this coating has a great disadvantage in wear resistance and is easily lost super-amphiphobic properties under the action of friction, so it is not suitable for long-term use.

[0004] Chinese patent CN107022279A discloses a method for preparing a super-hydrophobic coating with both transparency and good mechanical properties. The method prepares a super-hydrophobic coating by organic-inorganic hybrid technology, and applies the coating on the substrate by scraping method. However, scraping method is not suitable for large-area or complex-shaped substrates, limiting its feasibility in large-scale applications. In general, existing super-hydrophobic coatings have problems such as complicated preparation process, difficulty in large-scale application, poor wear resistance, and insufficient transparency. SUMMARY

[0005] The present application aims to provide a method for preparing a wear-resistant transparent flexible super-hydrophobic coating. The super-hydrophobic coating prepared by this method not only has excellent mechanical and chemical properties, but also has high transparency and flexibility.

[0006] The technical solutions adopted by the present application are as follows:

[0007] The method for preparing a wear-resistant transparent super-hydrophobic coating according to the present application comprises the following steps:

[0008] (1) mixing hydroxyl-terminated polydimethylsiloxane (HO-PDMS), gamma-aminopropyl triethoxysilane (KH550) and dibutyl tin dilaurate (DBTL) uniformly and then heating to react to obtain a modified precursor solution;

[0009] (2) adding epoxy resin into a solvent, stirring thoroughly, adding the modified precursor solution obtained in step (1) into the epoxy resin after the epoxy resin is completely swelled, and then heating to react to obtain a siloxane modified epoxy resin (PDMS-EP);

[0010] (3) dispersing nano-silicon dioxide (SiO2) in a solvent and stirring thoroughly to obtain a SiO2 dispersion;

[0011] (4) adding the modified epoxy resin obtained in step (2) into the dispersion obtained in step (4), adding a curing agent, and mixing uniformly to obtain a super-hydrophobic coating;

[0012] (5) spraying the coating obtained in step (4) onto the surface of a metal substrate by using an air spraying technology, and then drying in an oven to obtain a super-hydrophobic PDMS-EP / SiO2 coating.

[0013] Further, the solvent used in all the above steps is ethyl acetate.

[0014] Further, in step (1), the adding amount of the hydroxyl-terminated polydimethylsiloxane HO-PDMS, the gamma-aminopropyl triethoxysilane KH550 and the dibutyl tin dilaurate DBTL satisfies the mass ratio of 84-87:28-29:1.

[0015] Further, the type of the epoxy resin in the present application is E51, and the curing agent is polyether amine (D230), and the mass ratio of EP:D230 is 3:1.

[0016] Further, in step (1), the adding amount of the HO-PDMS, the KH550 and the DBTL is 9 g, 3 g and 0.1 ml respectively; the reaction condition of the coating modified precursor solution is 80-90℃ oil bath with 270-300 r / min magnetic stirring for 25-30 min; preferably, the reaction condition is 80℃, 270 r / min stirring for 30 min.

[0017] Further, in step (2), the concentration of the epoxy resin in the solvent is 30-31 wt%, and the adding amount of the epoxy resin and the modified precursor solution satisfies the mass ratio of 7.45-8.07:12.

[0018] The reaction condition is 80-90℃ oil bath with 140-180 r / min magnetic stirring for 3-4 h, and preferably, the reaction condition is 80℃, 140 r / min magnetic stirring for 3 h.

[0019] Further preferably, in the step (3), the concentration of the nano-silicon dioxide SiO2 in the solvent is 3.7-9.2 wt‰. The process parameters are magnetic stirring at 300-500 r / min for 15-20 min and ultrasonic dispersion for 20-30 min.

[0020] Further, in the step (4), the stirring condition is stirring at 800-1000 r / min for 10-15 min. The curing agent is polyetheramine D230, and the addition amount satisfies the mass ratio of epoxy resin EP: polyetheramine D230 = 3:1.

[0021] Further, in the step (5), the drying condition is curing in a constant-temperature air drying oven at 80-100℃ for 6-8 h.

[0022] Further, in the step (5), the substrate includes glass and fiber cloth.

[0023] A wear-resistant transparent flexible super-hydrophobic coating is prepared by the above method.

[0024] The wear-resistant transparent flexible super-hydrophobic coating can prevent various liquids from adhering to the surface of the coating, including but not limited to water, tea, milk, coffee, etc.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The preparation method adopted by the present application has the advantages of simple forming process and fast forming speed, and is suitable for large-scale preparation.

[0027] (2) The preparation method of the wear-resistant transparent flexible super-hydrophobic coating disclosed by the present application, wherein the epoxy resin serves as a matrix resin to play a bonding role, so that the super-hydrophobic coating is tightly combined with the glass substrate, and the strength and mechanical properties of the coating are improved.

[0028] (3) The wear-resistant transparent flexible super-hydrophobic coating prepared by the present application has good mechanical durability, and after being abraded by 400-mesh sandpaper and repeatedly peeled off by adhesive tape, the coating still exhibits a high hydrophobic state.

[0029] (4) The wear-resistant transparent flexible super-hydrophobic coating obtained by the preparation method of the present application has high transparency and flexibility, and the average transmittance in the 400-800 nm region reaches 80.7%, and the contact angle is still 151.6° after 500 times of repeated folding, maintaining the super-hydrophobic state.

[0030] (5) The wear-resistant transparent flexible super-hydrophobic coating prepared by the present application exhibits good self-cleaning performance and excellent anti-pollution ability to tea, coffee and milk and other pollutants. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Schematic diagram of preparation of the abrasion-resistant transparent flexible superhydrophobic coating in Example 1, 2 and 3 of the present application;

[0032] Figure 2 Schematic diagram of water contact angle of the coating prepared in Example 1, Comparative Example 1, Comparative Example 2 and Example 2 of the present application;

[0033] Figure 3 Scanning electron microscope (SEM) images of the abrasion-resistant transparent flexible superhydrophobic coating prepared in Example 1 and 2 of the present application;

[0034] Figure 4 Schematic diagram of the results of the friction and wear test of the abrasion-resistant transparent flexible superhydrophobic coating prepared in Example 1 of the present application;

[0035] Figure 5 Schematic diagram of the results of the adhesion test of the abrasion-resistant transparent flexible superhydrophobic coating prepared in Example 1 of the present application;

[0036] Figure 6 Schematic diagram of the results of the transparency test of the abrasion-resistant transparent flexible superhydrophobic coating prepared in Example 1 of the present application;

[0037] Figure 7 Schematic diagram of the flexibility test method and its results of the abrasion-resistant transparent flexible superhydrophobic coating prepared in Example 3 of the present application. DETAILED DESCRIPTION

[0038] The present application will be further described in conjunction with the accompanying drawings and examples. These examples are only used to illustrate the content of the present application and should not be regarded as a limitation on the scope of its application. Unless specifically noted in the examples, the specific conditions are operated according to the conventional experimental conditions; the reagents or instruments used, if not specifically mentioned, are conventional products available on the market and can be directly purchased.

[0039] The technical solution of the present application is:

[0040] The present application provides a preparation method of an abrasion-resistant transparent flexible superhydrophobic composite coating, which is described in detail in Figure 1 The steps include:

[0041] Step S1: Preparation of the substrate

[0042] The glass slide was placed in a beaker containing anhydrous ethanol and ultrasonically cleaned for 10 min to remove the oil on the surface. After cleaning, the glass slide was placed in an oven and dried at 60℃ for 10 min with air blowing to obtain a dried glass slide substrate.

[0043] Step S2: Preparation of the siloxane-modified epoxy resin

[0044] 9g of hydroxyl-terminated polydimethylsiloxane (HO-PDMS), 3g of γ-aminopropyl triethoxysilane (KH550), and 0.1ml of dibutyl tin dilaurate (DBTL) were uniformly mixed to obtain a mixed solution, and then the mixed solution was placed in an oil bath at 80°C and stirred at a speed of 270r / min for 30min to obtain a modified precursor solution.

[0045] The epoxy resin was added to the solvent and stirred thoroughly, and after the epoxy resin was completely swelled, it was added to the above modified precursor solution, stirred at 140r / min in an 80°C oil bath for 3h to obtain a siloxane-modified epoxy resin (PDMS-EP).

[0046] Step S3: Preparation of SiO2 suspension

[0047] The mass of the SiO2 filler was 0.2g, which was dispersed in 30ml of ethyl acetate, and the process parameters were magnetic stirring at 300-500r / min for 15-20min and ultrasonic dispersion for 20-30min to obtain a uniformly dispersed SiO2 suspension.

[0048] SiO2 has small particle size, increases transparency, has rough structure, and increases bonding strength, and becomes an ideal material for transparent super-hydrophobic coating.

[0049] Micro-nano filler is a key factor in determining whether the coating can achieve super-hydrophobicity. At the same time, the content of micro-nano filler also plays a crucial role in the hydrophobicity, wear resistance, and transparency of the coating. Therefore, in order to balance the hydrophobicity, transparency, and wear resistance, different filler masses (0.1g, 0.15g, 0.2g, 0.25g) were set, and the morphology and wettability of the coating under different filler contents were observed to determine the optimal ratio.

[0050] Further preferably, when the mass of SiO2 is 2g, the coating reaches a super-hydrophobic state, and the coating has excellent hydrophobicity, wear resistance, high transparency, and flexibility.

[0051] Step S4: Preparation of wear-resistant transparent flexible super-hydrophobic coating

[0052] The siloxane-modified epoxy resin (PDMS-EP) was poured into 5ml of ethyl acetate and stirred thoroughly to dissolve it.

[0053] Then the above solution was poured into the SiO2 dispersion liquid, stirred at 1000r / min for 15min to obtain a PDMS-EP / SiO2 suspension, and a curing agent was added and stirred uniformly to obtain a wear-resistant transparent flexible super-hydrophobic mixed coating.

[0054] The abrasion-resistant transparent flexible super-hydrophobic coating prepared in step S3 is sprayed onto the surface of the substrate by using air spraying technology. Then, it is placed in an oven for drying to obtain the abrasion-resistant transparent flexible super-hydrophobic PDMS-EP / SiO2 coating.

[0055] The spraying pressure is 0.2-0.4 MPa, and the spraying distance is always kept in the range of 15-20 cm.

[0056] The temperature of the oven drying is in the range of 80-100 ℃, and the drying time is 6-8 h.

[0057] The technical solutions of the present application and their effects are further illustrated below in combination with examples and comparative examples.

[0058] Example 1

[0059] In this example, the abrasion-resistant transparent flexible super-hydrophobic coating is prepared according to the following method.

[0060] (1) Preparation of a glass slide substrate

[0061] The glass slide is placed in an ethanol solution and ultrasonically cleaned for 10 min to remove the oil stains on the surface of the glass slide, and then placed in an oven for drying for 10 min to obtain a clean glass slide substrate.

[0062] (2) Preparation of a siloxane-modified epoxy resin:

[0063] 9 g of HO-PDMS, 3 g of KH550 and 0.1 ml of DBTL are mixed uniformly to obtain a mixed solution, and then the mixed solution is placed in an oil bath at 80 ℃ and stirred at a speed of 270 r / min for 30 min to obtain a modified precursor solution. The epoxy resin is added to the solvent and stirred thoroughly, and then added to the above modified precursor solution after the epoxy resin is completely swelled, and stirred at 140 r / min in an 80 ℃ oil bath for 3 h to obtain PDMS-EP.

[0064] Preparation of a SiO2 suspension

[0065] 0.2 g of SiO2 filler is dispersed in 30 ml of ethyl acetate, and the process parameters are magnetic stirring at 300-500 r / min for 15-20 min and ultrasonic dispersion for 20-30 min to obtain a uniformly dispersed SiO2 suspension.

[0066] Preparation of an abrasion-resistant transparent flexible super-hydrophobic coating:

[0067] PDMS-EP is poured into 5 ml of ethyl acetate and stirred thoroughly to dissolve it. Then, the above solution is poured into the SiO2 dispersion liquid, and stirred at 1000 r / min for 15 min to obtain a PDMS-EP / SiO2 suspension. After adding a curing agent and stirring uniformly, an abrasion-resistant transparent flexible super-hydrophobic mixed coating is obtained.

[0068] Preparation of wear-resistant transparent flexible super-hydrophobic coating

[0069] The wear-resistant transparent flexible super-hydrophobic coating prepared above is sprayed onto the surface of a glass slide using an air spraying technique. The spraying distance is kept within the range of 15-20 cm throughout the process. Then, it is placed in an oven and dried at 80°C for 6h to obtain a wear-resistant transparent flexible super-hydrophobic PDMS-EP / SiO2 coating.

[0070] Comparative Example 1

[0071] This example provides a coating, which differs from Example 1 in that only epoxy resin is used as the coating material, specifically comprising:

[0072] (1) Preparation of glass slide substrate:

[0073] The glass slide is placed in an ethanol solution and ultrasonically cleaned for 10 min to remove oil stains on the surface of the glass slide, and then placed in an oven and dried for 10 min to obtain a clean glass slide substrate.

[0074] (2) Preparation of coating:

[0075] 4g of epoxy resin is mixed with 1.33g of curing agent D230, and a glass rod is used to fully stir the mixture until the two components are uniformly mixed, and then sprayed onto the glass slide to obtain an epoxy resin coating.

[0076] Comparative Example 2

[0077] This example provides a hydrophobic coating, which differs from Example 1 in that only siloxane-modified epoxy resin is used as the coating material, and the specific content is as follows:

[0078] (1) Preparation of glass slide substrate:

[0079] The glass slide is placed in an ethanol solution and ultrasonically cleaned for 10 min to remove oil stains on the surface of the glass slide, and then placed in an oven and dried for 10 min to obtain a clean glass slide substrate.

[0080] (2) Preparation of siloxane-modified epoxy coating:

[0081] 9g of HO-PDMS, 3g of KH550 and 0.1ml of DBTL are mixed to obtain a mixed solution, which is then placed in an oil bath at 80°C and stirred at a speed of 270r / min for 30 min to obtain a modified precursor solution. 4g of epoxy resin is added to the solvent and stirred thoroughly. After the epoxy resin is completely swollen, it is added to the above-mentioned modified precursor solution, which is stirred in an oil bath at 80°C at a speed of 140r / min for 3h to obtain PDMS-EP.

[0082] Preparation of hydrophobic coating

[0083] 1.33g D230 curing agent was added into the above resin, and after stirring evenly, a super-hydrophobic coating was obtained.

[0084] Preparation of hydrophobic coating

[0085] The hydrophobic coating prepared above was sprayed onto the surface of a glass slide using air spraying technology. The spraying distance was maintained in the range of 15-20 cm during the process. Then, it was placed in an oven and dried at 80°C for 6h to obtain a hydrophobic PDMS-EP coating.

[0086] Example 2

[0087] The difference between this example and Example 1 is that the mass of SiO2 added in this example is different from that in Example 1. The specific implementation is:

[0088] (1) Preparation of glass slide substrate

[0089] The glass slide was placed in an ethanol solution and ultrasonically cleaned for 10 min to remove oil stains on the surface of the glass slide, and then dried in an oven for 10 min to obtain a clean glass slide substrate.

[0090] (2) Preparation of siloxane-modified epoxy resin:

[0091] 9g HO-PDMS, 3g KH550 and 0.1ml DBTL were mixed to obtain a mixed solution, and then the mixed solution was placed in an oil bath at 80°C and stirred at a speed of 270r / min for 30min to obtain a modified precursor solution. The epoxy resin was added to the solvent and stirred thoroughly. After the epoxy resin was completely swelled, it was added to the above modified precursor solution, and stirred at 140r / min in an 80°C oil bath for 3h to obtain PDMS-EP.

[0092] Preparation of SiO2 suspension

[0093] 0.15g SiO2 nano-filler was dispersed in 30ml ethyl acetate, and the process parameters were magnetic stirring at 300-500r / min for 15-20min and ultrasonic dispersion for 20-30min to obtain a uniformly dispersed SiO2 suspension.

[0094] Preparation of wear-resistant transparent flexible super-hydrophobic coating:

[0095] PDMS-EP was poured into 5ml ethyl acetate and stirred thoroughly to dissolve it. Then, the above solution was poured into the SiO2 dispersion liquid and stirred at 1000r / min for 15min to obtain a PDMS-EP / SiO2 suspension. A curing agent was added to obtain a wear-resistant transparent flexible super-hydrophobic mixed coating.

[0096] Preparation of wear-resistant transparent flexible superhydrophobic coating

[0097] The wear-resistant transparent flexible superhydrophobic coating prepared above was sprayed onto the surface of a glass slide using an air spraying technique. The spraying distance was maintained in the range of 15-20 cm throughout the process. Then, it was placed in an oven and dried at 80°C for 6h to obtain a wear-resistant transparent flexible superhydrophobic PDMS-EP / SiO2 coating.

[0098] Example 3

[0099] The preparation method of this example is different from that of Example 1 in that the coating substrate is a glass fiber cloth. Other details are the same as in Example 1, and the specific embodiment is as follows:

[0100] (1) Preparation of glass fiber substrate

[0101] The glass fiber cloth was cut into a size of 50mm x 50mm, and then it was immersed in an ethanol solution and ultrasonically cleaned for 10 min to remove oil stains on the surface of the glass fiber cloth. After cleaning, it was placed in an oven and dried for 30 min to obtain a clean glass fiber substrate.

[0102] (2) Preparation of siloxane-modified epoxy resin:

[0103] 9g HO-PDMS, 3g KH550 and 0.1ml DBTL were mixed uniformly to obtain a mixed solution, and then the mixed solution was placed in an 80°C oil bath and stirred at a speed of 270r / min for 30 min to obtain a modified precursor solution. The epoxy resin was added to the solvent and stirred thoroughly. After the epoxy resin was completely swollen, it was added to the above-mentioned modified precursor solution, and stirred at a speed of 140r / min in an 80°C oil bath for 3h to obtain PDMS-EP.

[0104] Preparation of SiO2 suspension

[0105] 0.2g of SiO2 nano-filler was dispersed in 30ml of ethyl acetate, and the process parameters were magnetic stirring at a speed of 300-500r / min for 15-20min and ultrasonic dispersion for 20-30min to obtain a uniformly dispersed SiO2 suspension.

[0106] Preparation of wear-resistant transparent flexible superhydrophobic coating:

[0107] PDMS-EP was poured into 5ml of ethyl acetate and stirred thoroughly to dissolve it. Then, the above-mentioned solution was poured into the SiO2 dispersion liquid and stirred at a speed of 1000r / min for 15min to obtain a PDMS-EP / SiO2 suspension. A curing agent was added to obtain a wear-resistant transparent flexible superhydrophobic mixed coating.

[0108] Preparation of wear-resistant transparent flexible superhydrophobic coating

[0109] The abrasion-resistant transparent flexible super-hydrophobic coating prepared above was sprayed onto the surface of a glass slide using an air spraying technique. The spraying distance was kept in the range of 15-20 cm throughout the process. Then, it was placed in an oven and dried at 80°C for 6 h to obtain the abrasion-resistant transparent flexible super-hydrophobic PDMS-EP / SiO2 coating.

[0110] In order to illustrate the effect of the abrasion-resistant corrosion-resistant epoxy-based composite coating provided by the present application, the following characterization tests were performed:

[0111] 1. Hydrophilic and hydrophobic contact angle test

[0112] The hydrophilic and hydrophobic contact angles of the coatings prepared in Test Example 1, Comparative Example 1, Comparative Example 2, and Example 2 were tested using an OCA40 type surface contact angle measuring instrument.

[0113] 2. Coating surface morphology test

[0114] A field emission scanning electron microscope (SEM, SU8220) was used to observe the surface morphology of the coating.

[0115] The surface morphology of the coating was observed to obtain intuitive visual information, thereby better understanding the morphological characteristics of the coating.

[0116] 3. Abrasion resistance test

[0117] The abrasion-resistant transparent flexible super-hydrophobic coating prepared in Example 1 was subjected to a cyclic friction test using 400-mesh sandpaper and a 100g weight.

[0118] 4. Adhesion test

[0119] The adhesion strength of the super-hydrophobic coating was tested according to the ISO-2409 standard. First, a 2mm x 2mm grid was scratched on the surface of the coating obtained in Example 1 using a cross-cut knife. Then, the surface of the coating was cleaned with a soft brush to remove debris, and a high-viscosity adhesive tape was tightly adhered to the grid. Next, one end of the tape was grabbed and torn off at a 60° angle within 0.5-1.0 seconds, and finally, the state of the grid area was checked.

[0120] 5. Transparency test

[0121] The light transmittance of the coating was tested using an ultraviolet-visible spectrophotometer.

[0122] 6. Flexibility test

[0123] The abrasion-resistant transparent flexible super-hydrophobic PDMS-EP / SiO2 coating was prepared on a glass fiber cloth, subjected to a repeated bending and twisting test, and the surface morphology was observed and the contact angle was tested.

[0124] The test results are as follows:

[0125] from Figure 2 As shown in Figure (a), the contact angle of the wear-resistant, transparent, flexible, superhydrophobic coating prepared in Example 1 is 155.5 ± 2.8°. The coating exhibits superhydrophobic properties, attributed to the synergistic effect between the epoxy resin and the nanoparticles. In contrast, the contact angle of the epoxy resin coating prepared in Comparative Example 1 is only 67.2 ± 2.5°. Figure 2 Figure (b) shows that it is a hydrophilic epoxy resin. In Comparative Example 2, from Figure 2 As shown in Figure (c), the contact angle of the superhydrophobic coating is 112.0 ± 1.6°, which is an increase compared to Comparative Example 1, but still much lower than that of Example 1. This is because the lack of filler to create surface roughness prevents the surface from achieving a superhydrophobic state. Figure 2 As can be observed in Figure (d), the contact angle of the coating in Example 2 is 138.5 ± 3.4°, which is significantly smaller than that in Example 1. This is because the epoxy resin content is higher and the nanoparticle content is lower, resulting in a reduction in roughness and hydrophobicity.

[0126] The above embodiments have provided a detailed description of the technical solution of the present invention. It should be understood that these are merely specific embodiments of the present invention and do not limit the scope of protection of the present invention. Any modifications, additions, or substitutions made within the scope of the principles of the present invention should be included within the scope of protection of the present invention.

[0127] The influence of morphology on the hydrophobic properties of the coating was further explained by testing the microstructure of the coating surface. The wear-resistant, transparent, flexible, superhydrophobic coating surface prepared in Example 1 was almost completely covered by silica nanoparticles, effectively forming a surface micro / nano rough structure. Figure 3 Figure (a) shows the coating surface nanoparticles prepared in Example 2, which are tightly encapsulated and embedded in the epoxy resin (EP) matrix, resulting in fewer surface protrusions. Figure 3 As shown in Figure (b), the roughness is not significant enough, resulting in a significant decrease in hydrophobic properties compared to the coating prepared in Example 1.

[0128] The superhydrophobic, wear-resistant, transparent, and flexible coating prepared in Example 1 maintained excellent hydrophobic properties throughout the entire wear process. After 600 cm of friction, the coating's WCA was 146.1 ± 0.2° and SA was 5° (see Example 1). Figure 4This indicates that the coating has a long service life under mechanical friction, mainly due to the following two aspects: Firstly, the siloxane-modified epoxy resin not only retains the excellent bonding strength of epoxy resin, but also, due to the addition of PDMS, allows the contact surface to undergo certain deformation and flow during friction, thereby dispersing the stress caused by friction. Secondly, the hydrophobic fumed silica nanoparticles have high strength and self-lubricating properties, and can spontaneously form a lubricating film at the friction interface. This film has good anti-wear and friction-reducing properties, effectively reducing the wear of the coating.

[0129] A tape peel test was conducted on the wear-resistant, transparent, flexible, superhydrophobic coating prepared in Example 1, comparing it with the coating before peeling ( Figure 5 (middle) (a) (back) Figure 5 The photograph of the coating in Figure (b) shows that the crisscross area on the surface is almost intact, the peeling area at the cross-cut is less than 5%, the adhesion of the coating reaches level 1, which meets the requirements for commercial use, and the water contact angle of the coating is 151.9±1.2°, which is still in a superhydrophobic state.

[0130] The light transmittance of the wear-resistant, transparent, flexible, superhydrophobic coating prepared in Example 1 was tested using a UV-Vis spectrophotometer. The results showed that ( Figure 6 (Figure (a)) The average transmittance of the coating in the 400-800nm ​​region is 80.7%. When the coating sprayed on the glass substrate is placed on paper, the text on the paper can be clearly seen through the coating.

[0131] The flexibility of the wear-resistant transparent flexible superhydrophobic coating prepared in Example 3 was tested by repeated bending and torsion tests. Figure 7 (Figure (a)) After repeated folding within the range of 0–180℃ and 500 folding cycles, WCA and SA showed no significant attenuation. Figure 7 As shown in Figure (b), the coating maintains a high degree of hydrophobicity. No delamination or cracking was observed. Figure 7 As shown in Figures (c-d), the microstructure remains similar to that of the original coating.

Claims

1. A method for preparing a transparent, flexible, wear-resistant superhydrophobic coating, characterized in that : comprising the following steps: (1) mixing hydroxyl-terminated polydimethylsiloxane HO-PDMS, gamma-aminopropyl triethoxysilane KH550 and dibutyltin dilaurate DBTL uniformly and then heating to react to obtain a modified precursor solution; (2) adding epoxy resin into a solvent, stirring thoroughly, and then adding into the modified precursor solution obtained in step (1) after the epoxy resin is fully swollen, and heating to react to obtain a siloxane-modified epoxy resin PDMS-EP; (3) dispersing nano-silicon dioxide SiO2 in a solvent, and stirring thoroughly to obtain a SiO2 dispersion; (4) adding the siloxane-modified epoxy resin obtained in step (2) into the SiO2 dispersion obtained in step (3), adding a curing agent, and mixing uniformly to obtain a super-hydrophobic coating; (5) spraying the coating obtained in step (4) onto a substrate surface by using air spraying technology, and drying in an oven to obtain a wear-resistant transparent flexible super-hydrophobic coating PDMS-EP / SiO2.

2. The method of claim 1, wherein the transparent, flexible, superhydrophobic coating is abrasion resistant. The solvent used in all steps is ethyl acetate.

3. The method of claim 1, wherein the transparent, flexible, superhydrophobic coating is prepared by the steps of: In step (1), the mass ratio of the adding amounts of the hydroxyl-terminated polydimethylsiloxane HO-PDMS, the gamma-aminopropyl triethoxysilane KH550 and the dibutyltin dilaurate DBTL satisfies: 84-87: 28-29:

1.

4. The method of claim 1, wherein the transparent flexible superhydrophobic coating is prepared by, In step (1), the reaction conditions for obtaining the modified precursor solution are 25-30 min of magnetic stirring at 270-300 r / min in an 80-90 ℃ oil bath.

5. The method of claim 1, wherein the transparent, flexible, superhydrophobic coating is prepared by, In step (2), the concentration of the epoxy resin in the solvent is 30-31 wt%, and the mass ratio of the adding amounts of the epoxy resin and the modified precursor solution satisfies: 7.45-8.07: 12; The type of the epoxy resin is E51, and the reaction conditions are 3-4 h of magnetic stirring at 140-180 r / min in an 80-90 ℃ oil bath.

6. The method of claim 1, wherein the transparent, flexible, superhydrophobic coating is prepared by, In step (3), the process parameters are 20-30 min of ultrasonic dispersion and 15-20 min of magnetic stirring at 300-500 r / min; and the concentration of the nano-silicon dioxide SiO2 in the solvent is 3.7-9.2 wt‰.

7. The method of claim 1, wherein the transparent, flexible, superhydrophobic coating is prepared by, In step (4), the mixing uniformity is achieved by stirring at 800-1000 r / min for 10-15 min; and the curing agent is polyetheramine D230, and the mass ratio of the adding amounts of the epoxy resin EP and the polyetheramine D230 satisfies: 3:

1.

8. The method of claim 1, wherein the transparent, flexible, superhydrophobic coating is prepared by, In step (5), the conditions for oven drying are 6-8 h of curing in a 80-100 ℃ constant-temperature air drying oven.

9. The method of claim 1, wherein the transparent, flexible, superhydrophobic coating is prepared by, In step (5), the substrate includes a glass slide and a glass fiber cloth.

10. A wear-resistant transparent flexible super-hydrophobic coating prepared by the preparation method of any one of claims 1-9.

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