A superhydrophobic coating and its preparation method

Abstract

This invention belongs to the field of surface treatment, specifically relating to a superhydrophobic coating and its preparation method. The preparation method of the hydrophobic coating includes: 1) dissolving zinc and aluminum nitrates in water to obtain solution A, dissolving NaNO3 and NaOH in water to obtain solution B, mixing solution A and solution B, heating, stirring evenly, and allowing to stand for aging to obtain a nitrate-intercalated zinc-aluminum layered bimetallic hydroxide; 2) mixing the nitrate-intercalated zinc-aluminum layered bimetallic hydroxide with Na2MoO4 to prepare a zinc-aluminum layered bimetallic hydroxide by anion exchange method; 3) hydrophobically modifying the zinc-aluminum layered bimetallic hydroxide to obtain a modified zinc-aluminum layered bimetallic hydroxide; 4) mixing the modified zinc-aluminum layered bimetallic hydroxide with polymer resin, diluent, and curing agent to obtain a superhydrophobic coating material, and curing to obtain a coating. The superhydrophobic coating provided by this invention has antifouling properties, anti-icing properties, and corrosion resistance.

Description

Technical Field

[0001] This invention belongs to the field of surface treatment, specifically relating to a superhydrophobic coating and its preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Marine biofouling and equipment surface icing affect the performance and lifespan of marine equipment, increase operating and maintenance costs, and even cause personal injury and economic losses. Therefore, they have always been two major obstacles to the development and utilization of marine resources. To date, coating is the most economical and effective measure to prevent marine corrosion and biofouling. However, traditional polymer coatings have many drawbacks, such as limited functionality, short lifespan, and poor durability. In recent years, superhydrophobic materials have attracted attention due to their self-cleaning, antifouling, and anti-corrosion properties; however, they often possess only a single property, limiting their application in harsh environments. Therefore, there is an urgent need to develop a superhydrophobic coating that integrates antifouling, anti-icing, and corrosion resistance properties. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a superhydrophobic coating and its preparation method. The superhydrophobic coating provided by the present invention has antifouling properties, anti-icing properties, and corrosion resistance.

[0005] To achieve the above objectives, a first aspect of the present invention provides a method for preparing a superhydrophobic coating, comprising:

[0006] 1) Dissolve zinc and aluminum nitrates in water to obtain solution A, dissolve NaNO3 and NaOH in water to obtain solution B, mix solution A and solution B, heat, stir evenly, and let stand to age to obtain nitrate-intercalated zinc-aluminum layered bimetallic hydroxide.

[0007] 2) Zinc-aluminum layered bimetallic hydroxide with nitrate intercalation was mixed with Na2MoO4 and then prepared by anion exchange.

[0008] 3) Hydrophobic modification of zinc-aluminum layered bimetallic hydroxide was performed to obtain modified zinc-aluminum layered bimetallic hydroxide;

[0009] 4) The modified zinc-aluminum layered bimetallic hydroxide is mixed with polymer resin, diluent and curing agent to obtain a superhydrophobic coating material, and then cured to obtain a coating.

[0010] In some embodiments, the water is deionized water, distilled water, or pure water.

[0011] In some implementations, in step 1), the heating is performed by heating to 45-85°C and then holding the temperature.

[0012] In some embodiments, in step 2), the nitrate-intercalated zinc-aluminum layered bimetallic hydroxide is dissolved in water with Na2MoO4, stirred to react, and centrifuged to obtain a precipitate of zinc-aluminum layered bimetallic hydroxide.

[0013] In some embodiments, in step 3), zinc-aluminum layered bimetallic hydroxide and stearate are dissolved in deionized water, stirred to react, centrifuged, and the resulting precipitate is hydrophobically modified zinc-aluminum layered bimetallic hydroxide.

[0014] In some embodiments, the zinc nitrate is Zn(NO3)2 or Zn(NO3)2·6H2O, and the aluminum nitrate is Al(NO3)3 or Al(NO3)3·9H2O. 2+ With Al 3+ The molar ratio is (1.5-2.5):1.

[0015] In some implementations, the molar ratio of NaNO3 to NaOH is 2:(7-11).

[0016] In some embodiments, solution A and solution B are mixed in a ratio of (0.5-1.5):1.

[0017] In some embodiments, in step 1), solution A and solution B are mixed and then heated in an oil bath at a temperature of 55-75°C for 14-34 hours, and aged for 8-16 hours.

[0018] In some embodiments, in step 2), the nitrate-intercalated zinc-aluminum layered bimetallic hydroxide and Na2MoO4 are dissolved in deionized water, stirred and aged under a nitrogen atmosphere to obtain the zinc-aluminum layered bimetallic hydroxide.

[0019] In some embodiments, nitrate-intercalated zinc-aluminum layered bimetallic hydroxide is dissolved in deionized water at a mass ratio of (2-5):1 with Na2MoO4.

[0020] In some embodiments, nitrate-intercalated zinc-aluminum layered bimetallic hydroxide and inorganic sodium salt are dissolved in deionized water to obtain a suspension. The suspension is stirred in an oil bath at 65-75°C for 8-16 hours under a nitrogen atmosphere and aged for 4-8 hours to obtain zinc-aluminum layered bimetallic hydroxide.

[0021] In some embodiments, the stearate is one of sodium stearate and magnesium stearate, preferably sodium stearate.

[0022] In some embodiments, the mass ratio of zinc-aluminum layered bimetallic hydroxide to sodium stearate is 1:(1-3); preferably 2:3.

[0023] In some embodiments, zinc-aluminum layered bimetallic hydroxide and stearate are dissolved in deionized water and kept at 80-120°C for 6-10 hours to obtain hydrophobically modified zinc-aluminum layered bimetallic hydroxide.

[0024] In some embodiments, the mass ratio of the hydrophobically modified zinc-aluminum layered bimetallic hydroxide, polymer resin, diluent and curing agent is (1-5):5:5:5.

[0025] In some embodiments, the polymer resin is any one of epoxy resin, polyurea resin, acrylic resin, or polyurethane resin.

[0026] A second aspect of the present invention provides a superhydrophobic coating obtained by the above preparation method.

[0027] The beneficial effects of this invention are as follows:

[0028] 1. The superhydrophobic coating material prepared in this invention is sprayed onto the substrate surface. The bimetallic hydroxide nanoparticles in the coating form a micro-nano structure, giving the coating a certain roughness. This allows it to capture air at the solid-liquid interface, forming a stable gas film. Therefore, when water droplets fall onto the coating surface, the contact area between the water droplets and the coating is reduced, preventing corrosive ions from penetrating the coating. Furthermore, the two-dimensional layered structure of the layered bimetallic hydroxide acts as a good physical barrier against the diffusion of corrosive media, providing physical protection for the substrate.

[0029] 2. The MoO4 loaded between the layers of the zinc-aluminum layered bimetallic hydroxide superhydrophobic coating material prepared in this invention. 2- Or PO4 3- It can be released into the corrosive environment through ion exchange to retain corrosive Cl. - It extends to the interlayer and provides corrosion inhibition. Therefore, the superhydrophobic coating can effectively block H2O, O2, and Cl. - It resists corrosion from corrosive media and achieves excellent antifouling, anti-icing, and corrosion resistance in harsh environments. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 This is a flowchart illustrating the coating preparation process in Example 1 of the present invention;

[0032] Figure 2 These are SEM images of different coatings of the present invention; wherein, (a) and (b) are SEM images of the LDH-MoO4 coating of Comparative Example 3 at different magnification ratios, and (c) and (d) are SEM images of the LDH-MoO4-St coating of Example 1 at different magnification ratios.

[0033] Figure 3 The figures show the test results of the contact angles of carbon steel and different coatings of the present invention; where (a) is the test result of the contact angle of Q235 carbon steel surface, (b) is the test result of the contact angle of EP coating of Comparative Example 4, (c) is the test result of the contact angle of EP / LDH-MoO4 coating of Comparative Example 3, and (d) is the test result of the contact angle of EP / LDH-MoO4-St coating of Example 1.

[0034] Figure 4 The diagram shows the antifouling test process of the coating in Example 1 of the present invention and an optical photograph of droplets on the coating surface; wherein, (a) is Rhodamine B solution, (b) is milk, (c) is orange juice, (d) is muddy water, (e) is methylene blue solution, and (f) is an optical photograph of droplets on the coating surface.

[0035] Figure 5 The figures show the anti-icing test results of carbon steel and different coatings of the present invention; where (a) is Q235 carbon steel; (b) is the test result of EP coating of Comparative Example 4; and (c) is the anti-icing test result of coating of Example 1.

[0036] Figure 6 Impedance diagrams, phase angle diagrams, Nyquist diagrams, and equivalent circuit diagrams of the carbon steel and different coatings of Example 1 and Comparative Example 4 of the present invention are shown in the test data diagrams of Q235 carbon steel and coatings of Comparative Example 3 and Comparative Example 4; wherein, (a) is the impedance diagram, (b) is the phase angle diagram, and (c) is the Nyquist diagram.

[0037] Figure 7 This is a diagram illustrating the superhydrophobicity and corrosion resistance mechanism of the coating in Embodiment 1 of the present invention. Detailed Implementation

[0038] To address the problem that existing superhydrophobic coatings often possess only a single property, which limits their application scenarios, this invention proposes a superhydrophobic coating and its preparation method.

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0040] The materials used in the embodiments of this invention are all common commercially available materials, including epoxy resin E51, polyurea resin SJKR 909H, acrylic resin PMMA, and polyurethane resin TPU.

[0041] Example 1

[0042] This embodiment provides a method for preparing a superhydrophobic coating, the specific steps of which are as follows:

[0043] 0.06 mol of Zn(NO3)2·6H2O and 0.03 mol of Al(NO3)3·9H2O were dissolved in 100 mL of deionized water and placed in a 500 mL beaker under stirring at room temperature to obtain mixed solution A. 0.04 mol of NaNO3 and 0.18 mol of NaOH were dissolved in 100 mL of deionized water to form solution B. Solutions A and B in the beaker were mixed and heated in an oil bath at 65 °C with stirring for 24 h, then aged for 12 h. After filtration and cooling to room temperature, the mixture was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the mixture was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-NO3. - Powder, denoted as LDH-NO3. ZnAl-LDH-NO3 - The powder is made into nanosheets for later use.

[0044] ZnAl-LDH-MoO4 was prepared by anion exchange method. 2- The nanoparticles were prepared under a nitrogen atmosphere. To avoid contamination by nitrate anions, all solutions were prepared using boiled deionized water. Specifically, 2.4 g of ZnAl-LDH-NO3 was added... - Nanosheets were suspended in 100 mL of deionized water containing 1.2 g Na₂MoO₄·2H₂O. The suspension was vigorously stirred in an oil bath at 70 °C for 12 h, followed by aging for 6 h. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-MoO₄. 2- The powder is designated as LDH-MoO4.

[0045] Superhydrophobic ZnAl-LDH-MoO4 synthesized by hydrothermal method 2- Nanoparticles, specifically: 2g ZnAl-LDH-MoO4 2-The powder and 2g of sodium stearate (St) were dissolved in 100mL of deionized water. The solution was then transferred to a polytetrafluoroethylene (PTFE) reactor, placed in an oven, and kept at 100℃ for 8 hours. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 rpm for 3 minutes. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80℃ for 6 hours to obtain dry and pure ZnAl-LDH-MoO4. 2- -St powder, denoted as LDH-MoO4-St.

[0046] A diluent is prepared by mixing xylene and ethylene glycol in a volume ratio of 7:3.

[0047] Weigh out 3g of LDH-MoO4-St powder, 5g of epoxy resin E51, and 5g of the above-mentioned diluent, and mix them together. While sonicating at room temperature, stir with a glass rod until fully mixed. Then add 5g of 8538 curing agent and sonicate and stir for 20 minutes at room temperature to ensure thorough mixing. Next, place the coating in a vacuum drying oven and continuously evacuate for 5 minutes at room temperature to eliminate air bubbles, thus obtaining a superhydrophobic coating material.

[0048] Example 2

[0049] This embodiment provides a method for preparing a superhydrophobic coating, the specific steps of which are as follows:

[0050] 0.045 mol of Zn(NO3)2·6H2O and 0.03 mol of Al(NO3)3·9H2O were dissolved in 100 mL of deionized water and placed in a 500 mL beaker under stirring at room temperature to obtain mixed solution A. 0.04 mol of NaNO3 and 0.14 mol of NaOH were dissolved in 100 mL of deionized water to form solution B. 50 mL of solution A and 100 mL of solution B were mixed and heated in an oil bath at 60 °C with stirring for 20 h, then aged for 10 h. After filtration and cooling to room temperature, the mixture was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the mixture was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-NO3. - Powder, denoted as LDH-NO3. ZnAl-LDH-NO3 - The powder is made into nanosheets for later use.

[0051] ZnAl-LDH-MoO4 was prepared by anion exchange method. 2-The nanoparticles were prepared under a nitrogen atmosphere. To avoid contamination by nitrate anions, all solutions were prepared using boiled deionized water. Specifically, 3.6 g of ZnAl-LDH-NO3 was added... - Nanosheets were suspended in 100 mL of deionized water containing 1.2 g Na₂MoO₄·2H₂O. The suspension was vigorously stirred in an oil bath at 65 °C for 8 h, followed by aging for 8 h. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-MoO₄. 2- The powder is designated as LDH-MoO4.

[0052] Superhydrophobic ZnAl-LDH-MoO4 synthesized by hydrothermal method 2- Nanoparticles, specifically: 2g ZnAl-LDH-MoO4 2- The powder and 4g of sodium stearate (St) were dissolved in 100mL of deionized water. The solution was then transferred to a polytetrafluoroethylene (PTFE) reactor, placed in an oven, and kept at 80℃ for 10 hours. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 rpm for 3 minutes. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80℃ for 6 hours to obtain dry and pure ZnAl-LDH-MoO4. 2- -St powder, denoted as LDH-MoO4-St.

[0053] A diluent is prepared by mixing xylene and ethylene glycol in a volume ratio of 7:3.

[0054] Weigh 1g of LDH-MoO4-St powder, 5g of polyurea resin SJKR 909H, and 5g of the above diluent, and mix them. While sonicating at room temperature, stir with a glass rod until fully mixed. Then add 5g of 8538 curing agent and sonicate and stir for 20 minutes at room temperature to ensure thorough mixing. The coating is then placed in a vacuum drying oven and continuously evacuated for 5 minutes at room temperature to eliminate air bubbles, thus obtaining a superhydrophobic coating material.

[0055] Example 3

[0056] This embodiment provides a method for preparing a superhydrophobic coating, the specific steps of which are as follows:

[0057] 0.075 mol of Zn(NO3)2·6H2O and 0.03 mol of Al(NO3)3·9H2O were dissolved in 100 mL of deionized water and placed in a 500 mL beaker under stirring at room temperature to obtain mixed solution A. 0.04 mol of NaNO3 and 0.22 mol of NaOH were dissolved in 100 mL of deionized water to form solution B. 100 mL of solution A and 67 mL of solution B were mixed and heated in an oil bath at 45 °C with stirring for 34 h, then aged for 16 h. After filtration and cooling to room temperature, the mixture was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the mixture was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-NO3. - The powder is designated as LDH-NO3.

[0058] ZnAl-LDH-MoO4 was prepared by anion exchange method. 2- The nanoparticles were prepared under a nitrogen atmosphere. To avoid contamination by nitrate anions, all solutions were prepared using boiled deionized water. Specifically, 4.8 g of ZnAl-LDH-NO3 was added. - Nanosheets were suspended in 100 mL of deionized water containing 1.2 g Na₂MoO₄·2H₂O. The suspension was vigorously stirred in an oil bath at 75 °C for 8 h, followed by aging for 4 h. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-MoO₄. 2- The powder is designated LDH-MoO4. ZnAl-LDH-NO3... - The powder is made into nanosheets for later use.

[0059] Superhydrophobic ZnAl-LDH-MoO4 synthesized by hydrothermal method 2- Nanoparticles, specifically: 2g ZnAl-LDH-MoO4 2-The powder and 6g of magnesium sodium stearate (St) were dissolved in 100mL of deionized water. The solution was then transferred to a polytetrafluoroethylene (PTFE) reactor, placed in an oven, and kept at 120℃ for 6 hours. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 rpm for 3 minutes. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80℃ for 6 hours to obtain dry and pure ZnAl-LDH-MoO4. 2- -St powder, denoted as LDH-MoO4-St.

[0060] A diluent is prepared by mixing xylene and ethylene glycol in a volume ratio of 7:3.

[0061] Weigh out 5g of LDH-MoO4-St powder, 5g of acrylic resin PMMA, and 5g of the above-mentioned diluent, and mix them together. While sonicating at room temperature, stir with a glass rod until fully mixed. Then add 5g of 8538 curing agent and sonicate and stir for 20 minutes at room temperature to ensure thorough mixing. Next, place the coating in a vacuum drying oven and continuously evacuate for 5 minutes at room temperature to eliminate air bubbles, thus obtaining a superhydrophobic coating material.

[0062] Example 4

[0063] This embodiment provides a method for preparing a superhydrophobic coating, the specific steps of which are as follows:

[0064] Zn(NO3)2·6H2O (0.06 mol) and Al(NO3)3·9H2O (0.03 mol) were dissolved in 100 mL of deionized water and placed in a 500 mL beaker under stirring at room temperature to obtain mixed solution A. NaNO3 (0.04 mol) and NaOH (0.18 mol) were dissolved in 100 mL of deionized water to form solution B. Solutions A and B in the beaker were mixed and heated in an oil bath at 85 °C with stirring for 14 h, then aged for 8 h. After filtration and cooling to room temperature, the mixture was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the mixture was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-NO3. - Powder, denoted as LDH-NO3. ZnAl-LDH-NO3 - The powder is made into nanosheets for later use.

[0065] ZnAl-LDH-MoO4 was prepared by anion exchange method. 2-The nanoparticles were prepared under a nitrogen atmosphere. To avoid contamination by nitrate anions, all solutions were prepared using boiled deionized water. Specifically, 2.4 g of ZnAl-LDH-NO3 was added... - Nanosheets were suspended in 100 mL of deionized water containing 1.2 g Na₂MoO₄·2H₂O. The suspension was vigorously stirred in an oil bath at 70 °C for 12 h, followed by aging for 6 h. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-MoO₄. 2- The powder is designated as LDH-MoO4.

[0066] Superhydrophobic ZnAl-LDH-MoO4 synthesized by hydrothermal method 2- Nanoparticles, specifically: 2g ZnAl-LDH-MoO4 2- The powder and 2g of magnesium stearate were dissolved in 100mL of deionized water. The solution was then transferred to a polytetrafluoroethylene (PTFE) reactor, placed in an oven, and kept at 100℃ for 8 hours. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 rpm for 3 minutes. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80℃ for 6 hours to obtain dry and pure ZnAl-LDH-MoO4. 2- -St powder, denoted as LDH-MoO4-St.

[0067] A diluent is prepared by mixing xylene and ethylene glycol in a volume ratio of 7:3.

[0068] Weigh out 3g of LDH-MoO4-St powder, 5g of TPU polyurethane resin, and 5g of the diluted diluent, and mix them together. While sonicating at room temperature, stir with a glass rod until fully mixed. Then add 5g of 8538 curing agent and sonicate and stir for 20 minutes at room temperature to ensure thorough mixing. Next, place the coating in a vacuum drying oven and continuously evacuate for 5 minutes at room temperature to eliminate air bubbles, thus obtaining a superhydrophobic coating material.

[0069] Comparative Example 1

[0070] 0.06 mol of Zn(NO3)2·6H2O and 0.03 mol of Al(NO3)3·9H2O were dissolved in 100 mL of deionized water and placed in a 500 mL beaker under stirring at room temperature to obtain mixed solution A. 0.04 mol of NaNO3 and 0.18 mol of NaOH were dissolved in 100 mL of deionized water to form solution B. Solutions A and B in the beaker were mixed and heated in an oil bath at 65 °C with stirring for 24 h, then aged for 12 h. After filtration and cooling to room temperature, the mixture was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the mixture was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-NO3. - The powder is designated as LDH-NO3.

[0071] 1 g of LDH-NO3 powder and 1.53 g of sodium stearate (St) were dissolved in 100 mL of deionized water. The solution was then transferred to a polytetrafluoroethylene (PTFE) reactor, placed in an oven, and kept at 100°C for 8 hours. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 rpm for 3 minutes. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80°C for 6 hours to obtain dry and pure ZnAl-LDH-NO3. - -St powder. ZnAl-LDH-NO3 - -St powder is made into nanosheets for later use.

[0072] Preparation of ZnAl-LDH-NO3 - -St nanosheets were dissolved in 5 mL of deionized water (0.5 wt.%) and sonicated for 5 min. Then, each type of nanosheet was added to 50 g of epoxy resin E51 and stirred with a strong stirrer at room temperature for 20 min. Next, 15 g of 8538 curing agent was added to the EP / LDH mixture and stirred for 10 min to ensure thorough mixing. This mixture was labeled EP / LDH-NO3-St. The coating was then placed in a vacuum drying oven and continuously evacuated at room temperature for 5 min to eliminate air bubbles, thus obtaining a superhydrophobic coating material.

[0073] Comparative Example 2

[0074] 0.06 mol of Zn(NO3)2·6H2O and 0.03 mol of Al(NO3)3·9H2O were dissolved in 100 mL of deionized water and placed in a 500 mL beaker under stirring at room temperature to obtain mixed solution A. 0.04 mol of NaNO3 and 0.18 mol of NaOH were dissolved in 100 mL of deionized water to form solution B. Solutions A and B in the beaker were mixed and heated in an oil bath at 65 °C with stirring for 24 h, then aged for 12 h. After filtration and cooling to room temperature, the mixture was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the mixture was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-NO3. - The powder is designated as LDH-NO3.

[0075] Dissolve 0.2 mol of Na3PO4·12H2O in 500 mL of deionized water. Then add 0.5 g of ZnAl-LDH-NO3. - The sample was dispersed in solution and stirred at room temperature for 48 hours. After filtration and cooling to room temperature, it was transferred to a high-speed centrifuge at 6000 rpm for 3 minutes. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, it was placed in a vacuum drying oven at 80°C for 6 hours to obtain dry and pure ZnAl-LDH-PO4. 3- The powder is designated as LDH-PO4.

[0076] 1 g of LDH-PO4 powder and 1.53 g of sodium stearate (St) were dissolved in 100 mL of deionized water. The solution was then transferred to a polytetrafluoroethylene (PTFE) reactor, placed in an oven, and kept at 100°C for 8 hours. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 rpm for 3 minutes. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80°C for 6 hours to obtain dry and pure ZnAl-LDH-PO4. 3- -St powder. ZnAl-LDH-PO4 3- -St powder is made into nanosheets for later use.

[0077] The prepared ZnAl-LDH-PO4 3--St nanosheets were dissolved in 5 mL of deionized water (0.5 wt.%) and sonicated for 5 min. Then, each type of nanosheet was added to 50 g of epoxy resin E51 and stirred with a vigorous stirrer at room temperature for 20 min. Next, 15 g of 8538 curing agent was added to the EP / LDH mixture and stirred for 10 min to ensure thorough mixing. The coating was then placed in a vacuum drying oven and continuously evacuated at room temperature for 5 min to eliminate air bubbles, thus obtaining a superhydrophobic coating material.

[0078] Comparative Example 3

[0079] 0.06 mol of Zn(NO3)2·6H2O and 0.03 mol of Al(NO3)3·9H2O were dissolved in 100 mL of deionized water and placed in a 500 mL beaker under stirring at room temperature to obtain mixed solution A. 0.04 mol of NaNO3 and 0.18 mol of NaOH were dissolved in 100 mL of deionized water to form solution B. Solutions A and B in the beaker were mixed and heated in an oil bath at 65 °C with stirring for 24 h, then aged for 12 h. After filtration and cooling to room temperature, the mixture was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the mixture was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-NO3. - Powder, denoted as LDH-NO3. ZnAl-LDH-NO3 - The powder is made into nanosheets for later use.

[0080] ZnAl-LDH-MoO4 was prepared by anion exchange method. 2- The nanoparticles were prepared under a nitrogen atmosphere. To avoid contamination by nitrate anions, all solutions were prepared using boiled deionized water. Specifically, 2.5g of ZnAl-LDH-NO3 was added... - Nanosheets were suspended in 100 mL of deionized water containing 1.2 g Na₂MoO₄·2H₂O. The suspension was vigorously stirred in an oil bath at 70 °C for 12 h, followed by aging for 6 h. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-MoO₄. 2- The powder is designated as LDH-MoO4.

[0081] A diluent is prepared by mixing xylene and ethylene glycol in a volume ratio of 7:3.

[0082] Weigh out 3g of LDH-MoO4 powder, 5g of EP, and 5g of the above diluent, and mix them together. While sonicating at room temperature, stir with a glass rod until fully mixed. Then add 5g of 8538 curing agent and sonicate and stir for 20 minutes at room temperature to ensure thorough mixing. Next, place the coating in a vacuum drying oven and continuously evacuate for 5 minutes at room temperature to eliminate air bubbles, thus obtaining a superhydrophobic coating material.

[0083] Comparative Example 4

[0084] Weigh 5g of EP and 5g of the diluent from Example 1 and mix them. While sonicating at room temperature, stir with a glass rod until fully mixed. Then add 5g of 8538 curing agent and sonicate and stir for 20 minutes at room temperature to ensure thorough mixing. The coating is then placed in a vacuum drying oven and continuously evacuated for 5 minutes at room temperature to eliminate air bubbles, obtaining the coating material.

[0085] Experimental Example

[0086] The Q235 carbon steel was gradually polished smooth with 220-grit and 600-grit sandpaper respectively. After degreasing, it was cleaned with acetone in an ultrasonic cleaner for 10 minutes. Then, it was ultrasonically cleaned with anhydrous ethanol for 10 minutes and then ultrasonically cleaned with deionized water for 10 minutes. This process was to remove surface impurities. After cleaning, it was placed in a vacuum drying oven to dry.

[0087] The coating materials of the above embodiments and comparative examples were loaded into the spray gun chamber, and the coatings were sprayed onto different substrate surfaces using an air pressure of 50 kPa at a spraying distance of 20 cm. After spraying, the coatings were first placed in a vacuum drying oven at 60°C for 3 hours to ensure rapid pre-curing, and then cured at room temperature for 48 hours to obtain fully cured coatings.

[0088] The coating obtained above was tested, and its antifouling performance, anti-icing performance and corrosion resistance were tested.

[0089] The corrosion resistance was tested using a neutral salt spray test method: the temperature of the test chamber should be controlled at (35±2)℃, the humidity should be greater than 95%, the concentration of sodium chloride solution should be 5%±0.5%, the pH value should be 6.5~7.2, and artificial scratches with a width of 0.5mm should be made on the coating to observe the degree of corrosion at the scratches. Here, the coatings prepared by the coating materials of Example 1 and Comparative Examples 1-3 are used as examples to compare their corrosion resistance.

[0090] Neutral salt spray test data

[0091] Exposure time 100h 300h 500h Example 1 Slight corrosion Slight corrosion Minor pitting Comparative Example 1 Minor pitting Severe pitting slight peeling Comparative Example 2 Slight corrosion Severe corrosion Severe pitting Comparative Example 3 Slight corrosion Severe corrosion Severe pitting

[0092] Comparative Example 1, which did not undergo anion exchange, exhibited poor corrosion resistance, particularly after 300 hours, with the formation of large-sized blocky corrosion products and severe pitting. Comparative Example 2 used sodium phosphate, and Comparative Example 3 was unmodified; both coatings formed blocky corrosion products after 500 hours. Example 1 showed the least amount of corrosion products, with only slight pitting at 500 hours, significantly superior to Comparative Examples 1-3, demonstrating excellent corrosion resistance.

[0093] Figure 3 The graph shows the test results of the contact angles of Q235 steel, Comparative Example 4, Comparative Example 3, and Example 1. Figure 3 As can be seen from a, the contact angle of the Q235 carbon steel surface after sandpaper pretreatment is about 61.5±0.5°, indicating the hydrophilicity of the substrate surface. Figure 3 (b) The surface contact angle of the pure epoxy coating prepared on the surface of Q235 carbon steel is shown, which increases to 76.8 ± 0.5° compared with the bare carbon steel substrate, while still remaining hydrophilic. The contact angle of the EP / LDH-MoO4 coating surface formed by the unmodified LDH-MoO4 nanoparticles and the epoxy coating is further improved, reaching 90.2 ± 0.5°, see [reference needed]. Figure 3 (c) is a purely hydrophobic surface. However, the EP / LDH-MoO4-St coating prepared by spraying nanoparticles modified with sodium stearate achieved a contact angle of 156.3±0.5°, making it a superhydrophobic surface. (See...) Figure 3 (d) This is because the LDH-MoO4 nanoparticles were modified by introducing sodium stearate, a low surface area material, to prepare superhydrophobic LDH-MoO4-St nanoparticles. These particles created a certain surface roughness in the composite coating, and cavitation was generated in the surface depressions, which in turn formed a gas film between the liquid and the solid, reducing the contact area between the water droplets and the coating, thus exhibiting superhydrophobic properties.

[0094] Figure 4 For the antifouling performance test of the coating in Example 1, immersion in dye wastewater was used. The experimental liquids were Rhodamine B solution, milk, orange juice, muddy water, and methylene blue solution (0.5g of the corresponding test powder was dissolved in 30ml of deionized water and stirred evenly). These different liquids were placed in white plastic cups. Samples coated with the EP / LDH-MoO4-St coating were picked up with tweezers and then immersed in the different dye liquids for 1 minute before being removed. From the initial immersion of the carbon steel sample coated with the EP / LDH-MoO4-St in the dye wastewater to its subsequent removal, no residual contamination was observed on the sample surface. The low adhesion between the EP / LDH-MoO4-St coating and contaminants, as well as the low slip angle of the coating surface, contribute to the good antifouling performance of the coating surface.

[0095] Figure 5 The results of the anti-icing test are for the coatings in Q235 steel, Comparative Example 4, and Example 1. On the Q235 steel substrate, it can be clearly observed that water droplets begin to freeze after 45 seconds and are completely frozen after 75 seconds. On the EP / LDH-MoO4 coating surface, as shown... Figure 5 As shown in (b), the water droplet began to freeze after 70 seconds and was completely frozen after 157 seconds. Figure 5 As shown in (c), water droplets on the EP / LDH-MoO4-St coating surface began to freeze at 195 seconds and were completely frozen at 340 seconds, indicating that the superhydrophobic coating surface can significantly delay the freezing process.

[0096] Figure 6 The results show the electrochemical performance test results of the coatings in Q235 steel, Comparative Example 4, Comparative Example 3, and Example 1. In coating systems, a high impedance value in the low-frequency region and a higher phase angle in the high-frequency region are generally considered to indicate better corrosion resistance. Q235 carbon steel has the lowest impedance value (2.53 × 10⁻⁶). 3 Ω·cm 2 The Q235 carbon steel coated with EP benefits from the physical barrier properties of EP, resulting in a lower overall impedance modulus (Z). f =0.01Hz) is about two orders of magnitude higher than that of bare Q235 carbon steel, reaching 7.29×10 5 Ω·cm 2 For Q235 carbon steel coated with EP / LDH-MoO4, the physical barrier effect and active ion exchange of LDH-MoO4 itself enhance the corrosion resistance of the composite coating, thereby increasing its impedance value (Z). f =0.01Hz) reached 7.84×10 7 Ω·cm 2 For Q235 carbon steel coated with an EP / LDH-MoO4-St superhydrophobic coating, its hydrophobic properties reduce its impedance (Z). f The value (=0.01Hz) was further increased to 1.35×10 11 Ω·cm 2 It exhibits superior corrosion resistance.

[0097] Furthermore, the phase angle in the high-frequency region of the Bode plot is also a key parameter for evaluating the corrosion resistance of the coating. Figure 6As shown in (b), the phase angle of the bare Q235 carbon steel does not exhibit the typical trend of a coated pattern, and a significant peak appears in the mid-frequency region. This indicates that the bare Q235 carbon steel underwent severe corrosion in a 3.5 wt.% NaCl solution. Compared to other coated samples that did not show corrosion, the bare Q235 carbon steel generated solution resistance during the corrosion process. After applying different coatings, the phase angle trends of the three samples were generally consistent. It is evident from the figure that all coated samples exhibited a relatively wide plateau in the high-frequency region. More importantly, the Q235 carbon steel coated with the EP / LDH-MoO4-St superhydrophobic coating showed the highest phase angle value and the widest plateau region, demonstrating its superior anti-permeation performance. Figure 6 As shown in (c), the Nyquist plot illustrates the differences in corrosion resistance among different coatings. Generally, the larger the diameter of the capacitive arc in the Nyquist plot, the stronger the impermeability. The bare Q235 carbon steel exhibits the smallest capacitive arc, while the Q235 carbon steel coated with the EP / LDH-MoO4-St superhydrophobic coating has the largest diameter. These results are consistent with previous analyses, further demonstrating the superior impermeability of the EP / LDH-MoO4-St superhydrophobic coating.

[0098] Figure 7 This diagram illustrates the superhydrophobic and anti-corrosion mechanism of the EP / LDH-MoO4-St coating in Example 1. First, the superhydrophobic EP / LDH-MoO4-St nanoparticles create a micro / nano structure on the coating, giving it a certain roughness. This allows it to capture air at the solid-liquid interface, forming a stable gas film. Therefore, when water droplets fall onto the coating surface, the contact area between the droplets and the coating is reduced, preventing corrosive ions from penetrating the coating. Second, the two-dimensional layered structure of LDH acts as a good physical barrier against the diffusion of corrosive media, providing physical protection for the substrate. Furthermore, the MoO42- ions loaded between the layers of LDH-MoO4 can be released into the corrosive environment through ion exchange to trap corrosive Cl-. - It extends to the interlayer and provides corrosion inhibition. Therefore, the EP / LDH-MoO4-St superhydrophobic coating can effectively block H2O, O2, and Cl. - It resists corrosion from corrosive media and achieves excellent antifouling, anti-icing, and corrosion resistance in harsh environments.

[0099] The above tests are described using only some embodiments and comparative examples. Other embodiments also have the same or similar effects. The technical solution of the present invention has excellent anti-fouling performance, anti-icing performance and corrosion resistance, and achieves excellent protective performance in harsh environments.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a superhydrophobic coating material, characterized in that, include: 0.06 mol Zn(NO3)2·6H2O and 0.03 mol Al(NO3)3·9H2O were dissolved in 100 mL of deionized water and placed in a 500 mL beaker under stirring at room temperature to obtain mixed solution A. 0.04 mol NaNO3 and 0.18 mol NaOH were dissolved in 100 mL of deionized water to form solution B. Solutions A and B in the beaker were mixed and heated in an oil bath at 65 °C with stirring for 24 h, then aged for 12 h. After filtration and cooling to room temperature, the mixture was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the mixture was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-NO3. - Powder, denoted as LDH-NO3; ZnAl-LDH-NO3 - The powder was processed into nanosheets for later use. 2.4g ZnAl-LDH-NO3 - Nanosheets were suspended in 100 mL of deionized water containing 1.2 g Na₂MoO₄·2H₂O. The suspension was vigorously stirred in an oil bath at 70 °C for 12 h, then aged for 6 h. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 r / min for 3 min. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water, and this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80 °C for 6 h to obtain dry and pure ZnAl-LDH-MoO₄. 2- The powder is designated as LDH-MoO4. Weigh out 2g of ZnAl-LDH-MoO4 2- The powder and 2g of sodium stearate (St) were dissolved in 100mL of deionized water. The solution was then transferred to a polytetrafluoroethylene (PTFE) reactor, placed in an oven, and kept at 100℃ for 8 hours. After filtration and cooling to room temperature, the solution was transferred to a high-speed centrifuge at 6000 rpm for 3 minutes. The resulting precipitate was washed once with anhydrous ethanol and then once with deionized water; this washing process was repeated three times. Finally, the solution was placed in a vacuum drying oven at 80℃ for 6 hours to obtain dry and pure ZnAl-LDH-MoO4. 2- -St powder, denoted as LDH-MoO4-St; A diluent is prepared by mixing xylene and ethylene glycol in a volume ratio of 7:

3. Weigh 3g of LDH-MoO4-St powder, 5g of epoxy resin E51 and 5g of the above diluent and mix them. While sonicating at room temperature, stir with a glass rod until they are fully mixed. Then add 5g of 8538 curing agent and sonicate and stir for 20 minutes at room temperature to make them fully mixed. Then put the coating into a vacuum drying oven and continuously evacuate for 5 minutes at room temperature to eliminate air bubbles in the coating to obtain a superhydrophobic coating material.

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