A villous ZnO rod-PDMS based superhydrophobic coating and its preparation method
A cost-effective water-based method for growing ZnO nanorods on PDMS/ZnO nano-particles addresses the complexity and durability issues of existing superhydrophobic surface production, achieving high contact angles and long-term stability for applications in anti-icing and self-cleaning.
Patent Information
- Application Number
- CN202211735807.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-30
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2042-12-30
AI Technical Summary
Existing methods for producing superhydrophobic surfaces face challenges such as complex processes, high material costs, and poor long-term durability, as seen in the preparation of ZnO nanostructures on titanium substrates.
A simple and cost-effective method involving the growth of ZnO nanorods on a PDMS/ZnO nano-particle base using a water-based growth process, forming a 'velvet-like' structure with enhanced contact angles through the use of specific solvents and reactants.
The method produces a superhydrophobic coating with high contact angles (153° to 161°) and excellent chemical stability, suitable for large-scale production and applications in passive anti-icing, corrosion protection, and self-cleaning surfaces.
Smart Images
Figure CN116041743B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of preparation of super hydrophobic coatings, and in particular to a super hydrophobic coating based on villi-shaped ZnO rod-PDMS and a preparation method thereof. Background Art
[0002] Generally speaking, superhydrophobicity is achieved by developing micro- and nano-surface structures with rough textures and then modifying the sample surface with materials with low surface energy. Superhydrophobic surfaces have a variety of uses, including self-cleaning surfaces, anti-corrosion, antibacterial properties, oil-water separation, anti-icing, etc. Therefore, the current priority is to design a superhydrophobic coating with characteristics for practical applications.
[0003] Although there are many ways to construct different rough surface structures and super-hydrophobic surfaces with low surface energy, there are still many challenges in actually realizing these surfaces; for example, in the prior art, the application number is 201611046447.8, and the document name is a method for preparing antibacterial hydrophobic ZnO nanorods. The ZnO nanorods are prepared by using polished titanium sheets as a substrate. There are problems such as cumbersome preparation process, high material cost, and poor long-term durability.
[0004] To address these issues, we designed a new, simple and easy approach. In this study, we developed a unique superhydrophobic coating structure that is simple to manufacture. After testing and characterizing ZnO / PDMS substrates with different mass ratios, the optimal mass ratio was determined. Then, on this substrate, zinc oxide nanorods were grown on the surface by a hydrothermal method to produce a superhydrophobic coating with a very high contact angle. The resulting superhydrophobic coating also has excellent chemical properties and liquid repellency. Summary of the invention
[0005] To this end, the present invention provides a super-hydrophobic coating based on villi-like ZnO rod-PDMS and a preparation method thereof, so as to solve the problem in the prior art that the super-hydrophobic coating is difficult to prepare due to complicated preparation process, high material cost and poor long-term durability.
[0006] In order to achieve the above object, the present invention provides the following technical solutions:
[0007] According to the first aspect of the present invention, the present invention provides a super hydrophobic coating based on villi-like ZnO rods-PDMS, which is composed of a PDMS / ZnO nanoparticle substrate, a zinc acetate dihydrate seed solution sprayed on the surface of the PDMS / ZnO nanoparticle substrate, a nutrient solution made of zinc nitrate hexahydrate solution and hexamethylenetetramine, and ZnO rods staggeredly grown on the surface of the PDMS / ZnO nanoparticle substrate.
[0008] Further, the PDMS / ZnO nanoparticle substrate is formed by drying and curing PDMS prepolymer A, n - hexane solution, nano - zinc oxide, and curing agent B.
[0009] Further, the surface contact angle of the super - hydrophobic coating is from 153° to 161°.
[0010] Further, the average diameter of the nano - zinc oxide is 50 - 100 nanometers; the zinc nitrate hexahydrate solution is of AR grade, the hexamethylenetetramine is of AR grade, and the zinc acetate dihydrate seed solution is of AR grade.
[0011] According to the second aspect of the present invention, the present application provides a preparation method of a super - hydrophobic coating based on villous ZnO rod - PDMS, which is characterized by including the following steps:
[0012] (1) Add the PDMS prepolymer A solution to the n - hexane solution and stir well, then add nano - zinc oxide and stir well to make it evenly mixed, then add the PDMS curing agent B solution and stir well. Spin - coat the above - mixed PDMS / ZnO nanoparticle solution on a glass slide, and then cure it in a vacuum oven to obtain a PDMS / ZnO nanoparticle substrate;
[0013] (2) Spray the zinc acetate dihydrate seed solution on the obtained PDMS / ZnO nanoparticle substrate, then heat to evaporate the solvent, and repeat the above process six times; The zinc nitrate hexahydrate solution and the hexamethylenetetramine solution are fully mixed and stirred at room temperature and then filtered to obtain a nutrient solution; Vertically place the PDMS / ZnO nanoparticle substrate coated with the zinc acetate dihydrate seed solution into the polytetrafluoroethylene liner of a high - pressure reactor filled with the nutrient solution and react at 90 °C for 6 hours; After the temperature of the high - pressure reactor drops to room temperature, take out the sample, rinse the surface with deionized water, and then dry it in a nitrogen atmosphere for standby; Immerse the above sample in a 2wt% FAS - 17 solution, and then dry the surface of the sample to obtain a coating with ZnO rods grown on it.
[0014] Further, in step (1), after testing and characterizing ZnO / PDMS substrates with different mass ratios, the optimal mass ratio is determined. Add 2 g of the PDMS prepolymer A solution to 20 ml of the n - hexane solution and stir well for 30 minutes, then add 3 g of nano - zinc oxide and stir well for 30 minutes to make it evenly mixed, then add 0.2 g of the PDMS curing agent B solution and stir well for 30 minutes. Spin - coat the above - mixed PDMS / ZnO nanoparticle solution on a glass slide, and then cure it in a 60 °C vacuum oven for 5 hours to obtain a PDMS / ZnO nanoparticle substrate.
[0015] Further, in step (2), the method for preparing the coating with ZnO rods is as follows: Spray a 5-20 mM zinc acetate dihydrate seed solution onto the PDMS / ZnO nanoparticle substrate we prepared, then heat it at 120 °C for 5 minutes to evaporate the solvent, and repeat the above process six times; Filter the nutrient solution prepared by magnetically mixing a 25 mM zinc nitrate hexahydrate solution and a 25 mM hexamethylenetetramine solution at room temperature for 2 hours; Vertically place the PDMS / ZnO nanoparticle substrate coated with the zinc acetate dihydrate seed solution into the polytetrafluoroethylene liner of a high-pressure reactor containing the nutrient solution, and react at 90 °C for 6 hours; After the temperature of the high-pressure reactor drops to room temperature, take out the sample from the polytetrafluoroethylene liner, rinse the surface with deionized water, and then dry it in a nitrogen atmosphere for standby; Immerse the above sample in a 2 wt% FAS-17 solution for 10-50 minutes, and then dry the surface of the sample at 60 °C - 90 °C to obtain a coating with ZnO rods.
[0016] Further, the ratio of PDMS to zinc oxide is: PDMS:ZnO = 1:0.5 - 3, and the solvent is n-hexane.
[0017] Further, the prepolymer A in step (1) is Sylgard184A, the curing agent B is Sylgard184B, and the polymer usage ratio is A / B = 10:1, wt / wt.
[0018] Further, the 2 wt% FAS-17 solution is 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS-17).
[0019] The present invention has the following advantages:
[0020] 1. Zinc oxide rods are grown on the surface of the PDMS / ZnO nanoparticle substrate by the hydrothermal method, forming a villous structure on the rough surface, further improving the surface hydrophobic property and increasing the contact angle from 153° to 161°. Moreover, the method of growing ZnO rods on the surface by the hydrothermal method has low cost, is simple, fast, and easy to implement, and is easy for large-scale operation.
[0021] 2. The superhydrophobic coating has long-term stability. After testing, the superhydrophobic property of the coating does not change significantly after being exposed in the atmospheric environment for 180 days. The coating has a high contact angle, excellent long-term durability, and good acid and alkali resistance.
[0022] 3. The present invention prepares a PDMS / ZnO nanoparticle substrate with good hydrophobic properties, studies the influence of different masses of ZnO doping on the PDMS substrate, and this coating can be widely applied in fields such as passive anti-icing, anti-corrosion, and self-cleaning. Description of the Drawings
[0023] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.
[0024] The structures, ratios, sizes, etc. illustrated in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention.
[0025] Figure 1 Schematic diagram of the preparation process of the superhydrophobic coating of ZnO rod - PDMS provided by the present invention;
[0026] Figure 2 Scanning electron microscope images of the superhydrophobic coating of ZnO rod - PDMS provided by the present invention: (a, b) Images of ZnO rods grown on the surface of the PDMS substrate at different magnifications; (c, d) Images of ZnO rods grown on the PDMS / ZnO nanoparticle substrate at different magnifications;
[0027] Figure 3 Provided by the present invention: (a) Contact angles of the superhydrophobic coating exposed to the natural environment for different days, (b) Contact angles of several different types of droplets on the surface of the superhydrophobic coating, (c) Contact angles at different pH values, (d) Photos of different droplets on the surface of the superhydrophobic coating, (e) Photos of droplets with different pH values on the superhydrophobic surface. Specific embodiments
[0028] The following specific embodiments illustrate the embodiments of the present invention. Those familiar with this technology can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present invention.
[0029] Reagents and materials used in the present invention: zinc nitrate hexahydrate, hexamethylenetetramine, zinc acetate dihydrate, n - hexane, sodium dodecylbenzenesulfonate, polydimethylsiloxane, etc.
[0030] The surface morphology of the coating was analyzed by a field emission scanning electron microscope (GeminiSEM 500) in the present invention; the components of the synthesized samples were characterized by X-ray diffraction (XRD, D8DISCOVER, BRUKER, Germany), and the X-ray photoelectron spectroscopy (XPS) was measured on a K-Aepna XPS system (ThermoFisher, USA); the surface wettability was measured by a contact angle analyzer (KRUSS, DSA100), and the average value of five different points of a single sample was taken as the contact angle (CA) each time; all solutions were stirred by an electromagnetic stirrer (MYP2011-100).
[0031] like Figure 1 As shown in , it consists of a PDMS / ZnO nanoparticle substrate, a zinc acetate dihydrate seed solution sprayed on the surface of the PDMS / ZnO nanoparticle substrate, a solution nutrient solution made of zinc nitrate hexahydrate solution and hexamethylenetetramine, and ZnO rods staggeredly grown on the surface of the PDMS / ZnO nanoparticle substrate.
[0032] In the present application, specifically, the PDMS / ZnO nanoparticle substrate is formed by drying and curing PDMS prepolymer A, n-hexane solution, nano zinc oxide and curing agent B, and the PDMS / ZnO nanoparticle substrate is prepared by strictly controlling the ratio of ZnO and PDMS.
[0033] In the present application, the raw materials used are PDMS prepolymer (Sylgard 184A) and curing agent (Sylgard 184B).
[0034] like Figure 2 and Figure 3 As shown, the surface contact angle of the superhydrophobic coating is 153° to 161°.
[0035] Specifically, the average diameter of nano zinc oxide is 50-100 nanometers; the zinc nitrate hexahydrate solution is AR grade, the hexamethylenetetramine is AR grade, and the zinc acetate dihydrate seed solution is AR grade.
[0036] According to a second aspect of the present invention, the present application provides a method for preparing a super hydrophobic coating based on a villi-like ZnO rod-PDMS, comprising the following steps:
[0037] (1) Figure 1 As shown, the PDMS prepolymer A solution is added to the n-hexane solution and stirred thoroughly, then the nano zinc oxide is added and stirred thoroughly to make it evenly mixed, then the PDMS curing agent B solution is added and stirred thoroughly, the mixed PDMS / ZnO nanoparticle solution is spin-coated on a glass slide, and then cured in a vacuum oven to obtain a PDMS / ZnO nanoparticle substrate;
[0038] (2) As Figure 1 shown, the zinc acetate dihydrate seed solution was sprayed onto the prepared PDMS / ZnO nanoparticle substrate, and then the solvent was evaporated by heating. The above process was repeated six times. The zinc nitrate hexahydrate solution and the hexamethylenetetramine solution were fully mixed and stirred at room temperature and then filtered to obtain the nutrient solution. The PDMS / ZnO nanoparticle substrate coated with the zinc acetate dihydrate seed solution on the surface was vertically placed into the PTFE liner of the autoclave containing the nutrient solution and reacted at 90 °C for 6 hours. After the temperature of the autoclave dropped to room temperature, the sample was taken out, the surface was rinsed with deionized water, and then dried under a nitrogen atmosphere for standby. The above sample was immersed in a 2 wt% FAS-17 solution, and then the surface of the sample was dried to obtain a coating with ZnO rods grown on it.
[0039] Among them, in step (1), after testing and characterizing ZnO / PDMS substrates with different mass ratios, the optimal mass ratio was determined. 2 g of the prepolymer A solution of PDMS was added to 20 ml of n-hexane solution and stirred well for 30 minutes, then 3 g of nano-zinc oxide was added and stirred well for 30 minutes to make it evenly mixed, and then 0.2 g of the curing agent B solution of PDMS was added and stirred well for 30 minutes. The above mixed PDMS / ZnO nanoparticle solution was spin-coated on a glass slide and then cured in a vacuum oven at 60 °C for 5 hours to obtain the PDMS / ZnO nanoparticle substrate, as Figure 1 shown.
[0040] Specifically, in step (2), the method for preparing the coating with ZnO rods is as follows: as Figure 1 , 10 mM of the zinc acetate dihydrate seed solution was sprayed onto the PDMS / ZnO nanoparticle substrate we prepared, and then the solvent was evaporated by heating at 120 °C for 5 minutes. The above process was repeated six times. 25 mM of the zinc nitrate hexahydrate solution and 25 mM of the hexamethylenetetramine solution were fully mixed and stirred at room temperature for 2 hours and then filtered to obtain the nutrient solution. The PDMS / ZnO nanoparticle substrate coated with the zinc acetate dihydrate seed solution on the surface was vertically placed into the PTFE liner of the autoclave containing the nutrient solution and reacted at 90 °C for 6 hours. After the temperature of the autoclave dropped to room temperature, the sample was taken out from the PTFE liner, the surface was rinsed with deionized water, and then dried under a nitrogen atmosphere for standby. The above sample was immersed in a 2 wt% FAS-17 solution for 10 - 50 minutes, and then the surface of the sample was dried at 60 °C - 90 °C to obtain a coating with ZnO rods grown on it, as Figure 2 shown.
[0041] In the examples of this application, the ratio of PDMS to ZnO is: PDMS:ZnO = 1:0.5 - 3, and the solvent is n-hexane.
[0042] Specifically, in step (1), the prepolymer A is Sylgard 184A, the curing agent B is Sylgard 184B, and the polymer usage ratio is A / B = 10:1, wt / wt.
[0043] The 2 wt% FAS-17 solution is 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS-17).
[0044] In the examples of this application, these micro-nanorods form a fluffy microscopic surface coating, as Figure 2 , the zinc oxide rods formed on the surface have a standard hexagonal fibrous wurtzite structure. These zinc oxide rods produce a "fuzzy" structure, reducing the surface roughness and increasing the contact angle. These "fuzzy" structures provide and lock in extra air, making it difficult for the liquid droplets to overcome the air pressure and contact the surface of the sample.
[0045] To better illustrate the technical solutions and technical effects of this application, the following examples are provided.
[0046] Example 1:
[0047] 1. As Figure 1 shown, add 4 g of the prepolymer A solution of PDMS to 20 ml of n-hexane solution and stir well for 30 minutes. Then add 3 g of zinc oxide nanoparticles and stir well for 30 minutes to mix evenly. Then add 0.4 g of the curing agent B solution of PDMS (A / B = 10:1, wt / wt) and stir well for 30 minutes. Spin-coat the above mixed PDMS / ZnO nanoparticle solution on a glass slide, and then cure it in a vacuum oven at 80 °C for 5 hours to obtain a PDMS / ZnO nanoparticle substrate.
[0048] 2. As Figure 1 shown, spray the 10 mM zinc acetate dihydrate seed solution on the PDMS / ZnO nanoparticle substrate we prepared, and then heat it at 120 °C for 5 minutes to evaporate the solvent. Repeat the above process three times; filter the 25 mM zinc nitrate hexahydrate solution and 25 mM hexamethylenetetramine solution after mixing and stirring well at room temperature for 2 hours to obtain a nutrient solution; vertically place the PDMS / ZnO nanoparticle substrate coated with the zinc acetate dihydrate seed solution into the PTFE liner of a high-pressure reactor filled with the nutrient solution and react at 90 °C for 6 hours; after the temperature of the high-pressure reactor drops to room temperature, take out the sample, rinse the surface with deionized water, and then dry it in a nitrogen atmosphere for standby. Immerse the above sample in a 2 wt% FAS-17 solution for 60 minutes, and then dry the surface of the sample at 90 °C to obtain a coating with ZnO rods. The contact angle of the obtained superhydrophobic coating can reach 153°.
[0049] Example 2:
[0050] 1. As shown in Figure 1 , add 2 g of the prepolymer A solution of PDMS into 20 ml of n - hexane solution and stir well for 30 minutes. Then add 3 g of nano - zinc oxide and stir well for 30 minutes to make it evenly mixed. Then add 0.2 g of the curing agent B solution of PDMS (A / B = 10:1, wt / wt) and stir well for 30 minutes. Spin - coat the above - mixed PDMS / ZnO nanoparticle solution on a glass slide, and then cure it in a vacuum oven at 60 °C for 5 hours to obtain the PDMS / ZnO nanoparticle substrate.
[0051] 2. As shown in Figure 1 , spray the 10 mM zinc acetate dihydrate seed solution on the PDMS / ZnO nanoparticle substrate we prepared, and then heat it at 120 °C for 5 minutes to evaporate the solvent. Repeat the above process six times; mix 25 mM zinc nitrate hexahydrate solution and 25 mM hexamethylenetetramine solution well at room temperature and stir for 2 hours, then filter to obtain the nutrient solution; vertically place the PDMS / ZnO nanoparticle substrate coated with the zinc acetate dihydrate seed solution into the inner lining of a high - pressure reactor filled with the nutrient solution and react at 90 °C for 6 hours; after the temperature of the high - pressure reactor drops to room temperature, take out the sample, rinse the surface with deionized water, and then dry it in a nitrogen atmosphere for standby. Immerse the above sample in a 2 wt% FAS - 17 solution for 60 minutes, and then dry the surface of the sample at 60 °C to obtain a coating with ZnO rods. As shown in Figure 2 , the contact angle of the obtained super - hydrophobic coating can reach 161°.
[0052] Example 3:
[0053] 1. As shown in Figure 1 , add 2 g of the prepolymer A solution of PDMS into 20 ml of n - hexane solution and stir well for 30 minutes. Then add 3 g of nano - zinc oxide and stir well for 30 minutes to make it evenly mixed. Then add 0.2 g of the curing agent B solution of PDMS (A / B = 10:1, wt / wt) and stir well for 30 minutes. Spin - coat the above - mixed PDMS / ZnO nanoparticle solution on a glass slide, and then cure it in a vacuum oven at 60 °C for 5 hours to obtain the PDMS / ZnO nanoparticle substrate.
[0054] 2. Spray the 10 mM zinc acetate dihydrate seed solution onto the PDMS / ZnO nanoparticle substrate we prepared, then heat it at 120 °C for 5 minutes to evaporate the solvent, and repeat the above process six times; mix 25 mM zinc nitrate hexahydrate solution and 25 mM hexamethylenetetramine solution thoroughly at room temperature for 2 hours and then filter to obtain the nutrient solution; vertically place the PDMS / ZnO nanoparticle substrate coated with the zinc acetate dihydrate seed solution into the PTFE liner of the autoclave containing the nutrient solution and react at 90 °C for 6 hours; after the temperature of the autoclave drops to room temperature, take out the sample, rinse the surface with deionized water, and then dry it in a nitrogen atmosphere for standby. Immerse the above sample in a 2 wt% FAS-17 solution for 30 minutes, and then dry the surface of the sample at 90 °C to obtain a coating with ZnO rods, as Figure 2 shown.
[0055] As Figure 3 shown, the superhydrophobic coating was tested. When observing the contact angles of the superhydrophobic coating exposed to the natural environment for different days, as Figure 3 (a); observe the contact angles of several different types of droplets on the surface of the superhydrophobic coating as Figure 3 (b), observe the contact angles at different pH values as Figure 3 (c), observe the photos of different droplets and droplets with different pH values on the surface of the superhydrophobic coating as Figure 3 (d) and Figure 3 (e), which confirms that the superhydrophobic coating has long-term stability after testing. The superhydrophobic performance of the coating does not change significantly after 180 days of atmospheric exposure. The prepared coating has a high contact angle, excellent long-term durability, and good acid and alkali resistance.
[0056] Although the present invention has been described in detail above with general descriptions and specific embodiments, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of the present invention claimed.
Claims
1. A superhydrophobic coating based on villous ZnO rods / PDMS, characterized in that, The method comprises a PDMS / ZnO nanoparticle substrate, a zinc acetate dihydrate seed solution, a zinc nitrate hexahydrate solution and a nutrient solution made of hexamethylenetetramine sprayed on the surface of the PDMS / ZnO nanoparticle substrate, and ZnO rods staggeredly grown on the surface of the PDMS / ZnO nanoparticle substrate, and includes the following steps: (1) adding a PDMS prepolymer A solution into n-hexane and stirring thoroughly, then adding nano zinc oxide and stirring thoroughly to mix evenly, then adding a PDMS curing agent B solution and stirring thoroughly, spin coating the mixed PDMS / ZnO nanoparticle solution onto a glass slide, and then curing in a vacuum oven to obtain a PDMS / ZnO nanoparticle substrate; (2) Spraying zinc acetate dihydrate seed solution on the prepared PDMS / ZnO nanoparticle substrate, then heating and evaporating the solvent, repeating the above process six times; fully mixing zinc nitrate hexahydrate solution and hexamethylenetetramine solution at room temperature, and then filtering to obtain a nutrient solution; vertically placing the PDMS / ZnO nanoparticle substrate coated with zinc acetate dihydrate seed solution into a polytetrafluoroethylene liner of an autoclave filled with nutrient solution and reacting at 90°C for 6 hours; after the temperature of the autoclave drops to room temperature, taking out the sample, rinsing the surface with deionized water, and then drying it in a nitrogen atmosphere for use; immersing the above sample in a 2wt% FAS-17 solution, and then drying the sample surface to obtain a coating with ZnO rods.
2. The superhydrophobic coating based on villous ZnO rods / PDMS according to claim 1, wherein, The PDMS / ZnO nanoparticle substrate is formed by drying and curing a PDMS prepolymer A solution, n-hexane, nano zinc oxide and a PDMS curing agent B solution.
3. The superhydrophobic coating based on villous ZnO rods / PDMS according to claim 1, characterized in that, The surface contact angle of the super hydrophobic coating formed by the ZnO rods is 153° to 161°.
4. The superhydrophobic coating based on villous ZnO rods / PDMS according to claim 2, wherein The average diameter of the nano zinc oxide is 50-100 nanometers; the zinc nitrate hexahydrate solution is of AR grade, the hexamethylenetetramine is of AR grade, and the zinc acetate dihydrate seed solution is of AR grade.
5. The superhydrophobic coating based on villous ZnO rods / PDMS according to claim 1, characterized in that, In step (1), after testing and characterizing ZnO / PDMS substrates with different mass ratios, the optimal mass ratio is determined, and then 2 g of PDMS prepolymer A solution is added to 20 ml of n-hexane and stirred for 30 minutes, and then 3 g of nano zinc oxide is added and stirred for 30 minutes to mix evenly, and then 0.2 g of PDMS curing agent B solution is added and stirred for 30 minutes, and the mixed PDMS / ZnO nanoparticle solution is spin-coated on a glass slide, and then cured in a vacuum oven at 60° C. for 5 hours to obtain a PDMS / ZnO nanoparticle substrate.
6. The superhydrophobic coating based on villous ZnO rods / PDMS according to claim 1, wherein In step (2), the method for preparing the coating with ZnO rods is as follows: Spray a 5-20 mM zinc acetate dihydrate seed solution onto the PDMS / ZnO nanoparticle substrate we prepared, then heat it at 120 °C for 5 minutes to evaporate the solvent, and repeat the above process six times; Filter the nutrient solution prepared by magnetically mixing a 25 mM zinc nitrate hexahydrate solution and a 25 mM hexamethylenetetramine solution at room temperature for 2 hours; Vertically place the PDMS / ZnO nanoparticle substrate coated with the zinc acetate dihydrate seed solution into the PTFE liner of a high-pressure reactor filled with the nutrient solution, and react at 90 °C for 6 hours; After the temperature of the high-pressure reactor drops to room temperature, take out the sample from the PTFE liner, rinse the surface with deionized water, and then dry it under a nitrogen atmosphere for standby; Immerse the above sample in a 2 wt% FAS-17 solution for 10-50 minutes, and then dry the surface of the sample at 60 °C - 90 °C to obtain a coating with ZnO rods.
7. The superhydrophobic coating based on villous ZnO rods / PDMS according to claim 1, characterized in that, The ratio of PDMS to zinc oxide: PDMS:ZnO = 1:0.5 - 3, and the solvent is n-hexane.
8. The superhydrophobic coating based on villous ZnO rods / PDMS according to claim 1, wherein In step (1), the prepolymer A is Sylgard 184A, the curing agent B is Sylgard 184B, and the polymer usage ratio is A / B = 10:1, wt / wt.