Epoxy resin-based superhydrophobic coating and method of making and use thereof

Abstract

The application discloses a preparation method of an epoxy resin-based super-hydrophobic coating and specifically comprises the following steps: step 1, preparing fluorinated modified SiO2 nanoparticles; step 2, preparing AgO / MgO / Mg(OH)2 composite materials; step 3, preparing an epoxy resin-based powder containing double fillers by using the fluorinated modified SiO2 nanoparticles prepared in step 1 and the AgO / MgO / Mg(OH)2 composite materials prepared in step 2 as the double fillers; step 4, performing sand blasting treatment on the surface of a steel material; step 5, preheating the sand-blasted steel material in an oven, using compressed air to electrostatically spray the epoxy resin-based powder containing double fillers on the surface of the preheated steel material, and then placing the steel material in the oven for heat preservation and furnace cooling until room temperature is reached. The application further discloses the epoxy resin-based super-hydrophobic coating and application. The application solves the problem of poor corrosion resistance and durability of the existing epoxy resin-based coating due to poor water repellency and self-cleaning property.

Description

Technical Field

[0001] This invention belongs to the technical field of preparation of corrosion-resistant, antifouling, and superhydrophobic coatings for marine engineering materials, and relates to epoxy resin-based superhydrophobic coatings. This invention also relates to the preparation method and application of epoxy resin-based superhydrophobic coatings. Background Technology

[0002] Carbon steel is currently the primary material used in ships, submarines, and offshore platforms. However, it is susceptible to corrosion from chloride ions, moisture, and oxygen in its operating environment, leading to material failure, significant waste, and safety issues. Epoxy resin coatings provide corrosion protection to carbon steel through physical isolation; however, the porosity created during the epoxy resin curing process results in unsatisfactory corrosion protection and biofouling problems during service. Adding inorganic antibacterial fillers to epoxy resin can fill some of the pores, improving barrier properties; simultaneously, the fillers' own antibacterial properties prevent biofouling. However, epoxy resin coatings prepared with added inorganic antibacterial fillers are either weakly hydrophilic or hydrophobic, have poor water resistance, and lack self-cleaning ability. This allows water molecules and corrosive molecules such as chloride ions to still penetrate the coating's pores and reach the steel substrate, corroding it and resulting in poor corrosion resistance and durability. Furthermore, even if microorganisms are killed by the antibacterial materials in the coating, they can easily remain on the surface, making the offshore equipment dirty and affecting its appearance.

[0003] Superhydrophobic coatings possess extreme water resistance, self-cleaning properties, and corrosion resistance. They reduce the contact area between water molecules and the coating surface, and the air cushion layer formed by the coating effectively blocks direct contact between corrosive media and the coating, thus extending the service life of epoxy resin coatings. Simultaneously, the self-cleaning properties of superhydrophobic coatings allow surface-killed bacteria to be washed away by running water, addressing aesthetic concerns related to the coating. Summary of the Invention

[0004] The purpose of this invention is to provide an epoxy resin-based superhydrophobic coating, which solves the problem of poor surface water repellency and self-cleaning properties of existing epoxy resin-based coatings, resulting in poor corrosion resistance and durability.

[0005] A second objective of this invention is to provide a method for preparing an epoxy resin-based superhydrophobic coating.

[0006] A third objective of this invention is to provide the application of epoxy resin-based superhydrophobic coatings in corrosion and fouling prevention.

[0007] The first technical solution adopted in this invention is a method for preparing an epoxy resin-based superhydrophobic coating, which specifically includes the following steps: Step 1: Prepare fluorinated modified SiO2 nanoparticles; Step 2: Prepare AgO / MgO / Mg(OH)2 composite material; Step 3: Using the fluorinated modified SiO2 nanoparticles obtained in Step 1 and the AgO / MgO / Mg(OH)2 composite material obtained in Step 2 as dual fillers, prepare epoxy resin-based powder containing dual fillers. Step 4: Sandblast the surface of the steel. Step 5: Place the sandblasted steel in an oven for preheating. Use compressed air to electrostatically spray epoxy resin-based powder containing double fillers onto the surface of the preheated steel. After spraying, place the steel in the oven for heat preservation and cool it to room temperature with the furnace.

[0008] The invention is further characterized by: The specific process of step 1 is as follows: 1H,1H,2H,2H-perfluorodecyltriethoxysilane is added to anhydrous ethanol and mixed evenly to prepare a perfluorodecyltriethoxysilane modified solution. Then, gas-phase hydrophobic SiO2 nanoparticles are added, and after magnetic stirring, centrifugation and drying are performed to obtain fluorinated modified SiO2 nanoparticles.

[0009] In step 1, the volume fraction of the perfluorodecyltriethoxysilane modification solution is 2.5% to 12.5%.

[0010] The specific process of step 3 is as follows: using the fluorinated modified SiO2 nanoparticles obtained in step 1 and the AgO / MgO / Mg(OH)2 composite material obtained in step 2 as dual fillers, the AgO / MgO / Mg(OH)2 composite material, fluorinated modified SiO2 nanoparticles and epoxy resin powder are mixed, and the mixed powder is ball-milled on a horizontal ball mill to obtain epoxy resin-based powder containing dual fillers. In step 3, the mass percentage of fluorinated modified SiO2 nanoparticles in the mixed powder is 2.5–10 wt%.

[0011] In step 3, the ball milling time is 2 to 6 hours.

[0012] The specific process of step 4 is as follows: place the steel in a sandblasting machine and use compressed air of 0.4 to 0.6 MPa to sandblast at a distance of about 20 to 30 mm from the sample.

[0013] The specific process of step 5 is as follows: the sandblasted steel is placed in an oven and preheated to 180-260°C. Using compressed air, epoxy resin-based powder containing double fillers is electrostatically sprayed onto the surface of the preheated steel. After the spraying is completed, the sample is placed in the oven and kept warm for 20-30 minutes before being cooled to room temperature with the oven.

[0014] The second technical solution adopted in this invention is an epoxy resin-based superhydrophobic coating, which is prepared by the above-mentioned method for preparing epoxy resin-based superhydrophobic coatings.

[0015] The third technical solution adopted in this invention is the application of epoxy resin-based superhydrophobic coatings in corrosion and fouling prevention.

[0016] The beneficial effects of this invention are as follows: This invention adds a self-made, low-cost, and antibacterial AgO / MgO / Mg(OH)2 composite material and a wear-resistant, hydrophobically modified SiO2 nanoparticle dual filler to epoxy resin powder. Utilizing the micro / nano structure constructed on the coating surface by the particle size difference of the dual filler and the low surface energy of the hydrophobically modified SiO2 nanoparticles, a superhydrophobic coating is obtained. Through the strong water-repellent properties and self-cleaning ability of the superhydrophobic coating, it effectively slows down the entry of water molecules and corrosive molecules into the coating and can remove microorganisms attached to the coating surface. Furthermore, the dual filler can fill some of the pores generated during epoxy resin curing, improving… This invention achieves high physical barrier properties while also providing antifouling and wear resistance, addressing issues such as poor corrosion resistance and unsightly surface finish due to microbial adhesion in existing epoxy resin-based antifouling coatings containing inorganic antibacterial materials, thus extending their service life. Furthermore, the invention utilizes electrostatic spraying to prepare the coating. During electrostatic spraying of epoxy resin powder containing dual fillers, the positively charged AgO / MgO / Mg(OH)2 composite material and negatively charged SiO2 nanoparticles, under the influence of an electrostatic field, allow the two fillers to align hierarchically, according to the principle of like charges repelling and unlike charges attracting, which is more conducive to the formation of surface micro / nano structures. Therefore, the prepared dual-filler epoxy resin-based superhydrophobic coating can provide durable corrosion and antifouling protection for carbon steel materials serving in marine environments. Attached Figure Description

[0017] Figures 1(a) to 1(c) show the water contact angles of the epoxy resin-based superhydrophobic coating prepared by electrostatic spraying using AgO / MgO / Mg(OH)2 composite material and SiO2 nanoparticles as dual fillers in the preparation method of epoxy resin-based superhydrophobic coating constructed by dual fillers in this invention. Figure 2 shows the three-dimensional morphology and surface roughness of the epoxy resin-based superhydrophobic coating prepared by electrostatic spraying using AgO / MgO / Mg(OH)2 composite material and SiO2 nanoparticles as dual fillers in the preparation method of epoxy resin-based superhydrophobic coating constructed by dual fillers of the present invention, using laser confocal scanning microscopy. Figure 3 This is the potentiodynamic polarization curve of the epoxy resin-based superhydrophobic coating prepared by electrostatic spraying using AgO / MgO / Mg(OH)2 composite material and SiO2 nanoparticles as dual fillers in the preparation method of epoxy resin-based superhydrophobic coating constructed by dual fillers in this invention. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] This invention relates to an epoxy resin-based superhydrophobic coating, which is a water-repellent, self-cleaning, durable corrosion-resistant, anti-fouling, low-cost, and environmentally friendly epoxy resin-based superhydrophobic coating. The preparation method of this epoxy resin-based superhydrophobic coating is carried out according to the following steps: Step 1: A certain volume of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was measured and added to anhydrous ethanol and mixed evenly to prepare 50 mL of perfluorodecyltriethoxysilane modification solution with a volume fraction of 2.5% to 12.5%. Then, 5 g of gas-phase hydrophobic SiO2 nanoparticles with a particle size of 30 nm were added. After magnetic stirring for 5 h, the mixture was centrifuged and dried to obtain fluorinated modified SiO2 nanoparticles.

[0020] Step 2: Prepare 50 mL of 0.37 mol / L AgNO3 solution and 25 mL of 0.74 mol / L NaOH solution. Add the NaOH solution dropwise to the AgNO3 solution under magnetic stirring, forming a brownish-yellow precipitate. Then, add 5 mol / L ammonia solution until the precipitate is completely dissolved, obtaining a silver ammonia solution. Next, add 2.0 g of commercially available MgO nanoparticles with a particle size of 30 nm to the silver ammonia solution and stir for 2 h. Separate reaction product 1 and the filtrate by vacuum filtration. Determine the silver ion content in the filtrate using the Volhard method to determine the amount of silver ions adsorbed by the MgO nanoparticles. Weigh out an amount of NaCl equal to the molar amount of adsorbed silver ions to prepare a 100 mL solution. Add the separated reaction product 1 to the NaCl solution and stir for 30 min. Vacuum filter to obtain reaction product 2, wash 2-3 times with deionized water, dry at 60℃ for 6 h, and then heat to 700℃ at a rate of 2℃ / min and hold for 8 h. Based on the silver ion adsorption capacity determined above, weigh out the corresponding amounts of K2S2O8 and NaOH according to n(K2S2O8) / n(Ag)=3 and n(NaOH) / n(Ag)=7, and dissolve them separately in 50 mL of deionized water. Heat the K2S2O8 and NaOH solutions to 60 °C and mix them. Add the material calcined at 700 °C in small amounts several times while stirring, and allow the oxidation reaction to proceed for 75 min. After the reaction is complete, filter the mixture and wash it 2-3 times with deionized water. Finally, dry it in a 60 °C oven for 6 h to obtain the AgO / MgO / Mg(OH)2 composite material.

[0021] Step 3: Using the fluorinated modified SiO2 nanoparticles obtained in Step 1 and the AgO / MgO / Mg(OH)2 composite material obtained in Step 2 as dual fillers, weigh and mix the AgO / MgO / Mg(OH)2 composite material (1.5 wt%), the fluorinated modified SiO2 nanoparticles (2.5–10 wt%), and the remainder as epoxy resin powder, so that the total mass is 20 g. Then, ball mill the mixed powder in a horizontal ball mill at a speed of 300 r / min for 2–6 h to obtain epoxy resin-based powder containing dual fillers.

[0022] Step 4: Place the steel (Q235 steel) in a sandblasting machine and use compressed air at 0.4–0.6 MPa to sandblast at a distance of approximately 20–30 mm from the sample. Simultaneously, tilt the sample at a 30° angle to avoid localized damage to the substrate and to prevent sandblasting dead zones. The impact of the sand particles on the surface removes grease, dirt, oxide layers, and rust, thereby improving coating adhesion.

[0023] Step 5: Place the sandblasted Q235 steel specimen in an oven and preheat it to 180–260°C. Using 0.8 MPa compressed air, electrostatically spray epoxy resin-based powder containing dual fillers onto the surface of the preheated Q235 steel specimen. After spraying, place the specimen in an oven and hold it at 220°C for 20–30 minutes, then cool it to room temperature with the oven.

[0024] Using the above preparation method, when the AgO / MgO / Mg(OH)2 composite material is added at 1.5 wt% and the SiO2 nanoparticles modified with 10% perfluorodecyltriethoxysilane are added at 8.5 wt%, the water contact angle is 153.7°, the surface roughness is 22.454 μm, and the lowest corrosion current density is 2.058 × 10⁻⁶. -9 A•cm -2 An epoxy resin-based superhydrophobic coating with a 99.9% E. coli sterilization rate and a cross-cut adhesion rating of 0.

[0025] Example 1 This invention discloses a method for preparing an epoxy resin-based superhydrophobic, corrosion-resistant, and antifouling coating using a dual-filler configuration, which specifically includes the following steps: Step 1: A certain volume of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was measured and added to anhydrous ethanol and mixed thoroughly to prepare 50 mL of a 7.5% (v / v) perfluorodecyltriethoxysilane modification solution. Then, 5 g of 30 nm hydrophobic SiO2 nanoparticles were added, and the mixture was magnetically stirred for 5 h, centrifuged, and dried to obtain fluorinated modified SiO2 nanoparticles.

[0026] Step 2: Prepare 50 mL of 0.37 mol / L AgNO3 solution and 25 mL of 0.74 mol / L NaOH solution. Add the NaOH solution dropwise to the AgNO3 solution under magnetic stirring, forming a brownish-yellow precipitate. Then, add 5 mol / L ammonia solution until the precipitate is completely dissolved, obtaining a silver ammonia solution. Next, add 2.0 g of commercially available MgO nanoparticles with a particle size of 30 nm to the silver ammonia solution and stir for 2 h. Separate reaction product 1 and the filtrate by vacuum filtration. Determine the silver ion content in the filtrate using the Volhard method to determine the amount of silver ions adsorbed by the MgO nanoparticles. Weigh out an amount of NaCl equal to the molar amount of adsorbed silver ions to prepare a 100 mL solution. Add the separated reaction product 1 to the NaCl solution and stir for 30 min. Vacuum filter to obtain reaction product 2, wash 2-3 times with deionized water, dry at 60℃ for 6 h, and then heat to 700℃ at a rate of 2℃ / min and hold for 8 h. Based on the silver ion adsorption capacity determined above, weigh out the corresponding amounts of K2S2O8 and NaOH according to n(K2S2O8) / n(Ag)=3 and n(NaOH) / n(Ag)=7, and dissolve them separately in 50 mL of deionized water. Heat the K2S2O8 and NaOH solutions to 60 °C and mix them. Add the material calcined at 700 °C in small amounts several times while stirring, and allow the oxidation reaction to proceed for 75 min. After the reaction is complete, filter the mixture and wash it 2-3 times with deionized water. Finally, dry it in a 60 °C oven for 6 h to obtain the AgO / MgO / Mg(OH)2 composite material.

[0027] Step 3: Using the fluorinated modified SiO2 nanoparticles obtained in Step 1 and the AgO / MgO / Mg(OH)2 composite material obtained in Step 2 as dual fillers, weigh and mix the AgO / MgO / Mg(OH)2 composite material (1.5wt%), the fluorinated modified SiO2 nanoparticles (10wt%), and the remaining epoxy resin powder to make a mass of 20g. Then, ball mill the mixed powder in a horizontal ball mill at a speed of 300r / min for 2h to obtain epoxy resin-based powder containing dual fillers.

[0028] Step 4: Place the Q235 steel in a sandblasting machine and use compressed air at 0.4 MPa to sandblast at a distance of approximately 20 mm from the sample. Simultaneously, tilt the sample at a 30° angle to avoid localized damage to the substrate and to prevent sandblasting dead zones. The impact of the sand particles on the surface removes grease, dirt, oxide layers, and rust, thereby improving coating adhesion.

[0029] Step 5: Place the sandblasted Q235 steel specimen in an oven and preheat it to 180°C. Using 0.6 MPa compressed air, electrostatically spray epoxy resin-based powder containing double fillers onto the surface of the Q235 steel specimen. After spraying, place the specimen in an oven and keep it at 180°C for 20 minutes, then cool it to room temperature with the oven.

[0030] Example 2 This invention discloses a method for preparing an epoxy resin-based superhydrophobic, corrosion-resistant, and antifouling coating using a dual-filler configuration, which specifically includes the following steps: Step 1: A certain volume of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was measured and added to anhydrous ethanol and mixed thoroughly to prepare 50 mL of a 10.0% (v / v) perfluorodecyltriethoxysilane modification solution. Then, 5 g of 30 nm hydrophobic SiO2 nanoparticles were added, and the mixture was magnetically stirred for 5 h, centrifuged, and dried to obtain fluorinated modified SiO2 nanoparticles.

[0031] Step 2: Prepare 50 mL of 0.37 mol / L AgNO3 solution and 25 mL of 0.74 mol / L NaOH solution. Add the NaOH solution dropwise to the AgNO3 solution under magnetic stirring, forming a brownish-yellow precipitate. Then, add 5 mol / L ammonia solution until the precipitate is completely dissolved, obtaining a silver ammonia solution. Next, add 2.0 g of commercially available MgO nanoparticles with a particle size of 30 nm to the silver ammonia solution and stir for 2 h. Separate reaction product 1 and the filtrate by vacuum filtration. Determine the silver ion content in the filtrate using the Volhard method to determine the amount of silver ions adsorbed by the MgO nanoparticles. Weigh out an amount of NaCl equal to the molar amount of adsorbed silver ions to prepare a 100 mL solution. Add the separated reaction product 1 to the NaCl solution and stir for 30 min. Vacuum filter to obtain reaction product 2, wash 2-3 times with deionized water, dry at 60℃ for 6 h, and then heat to 700℃ at a rate of 2℃ / min and hold for 8 h. Based on the silver ion adsorption capacity determined above, weigh out the corresponding amounts of K2S2O8 and NaOH according to n(K2S2O8) / n(Ag)=3 and n(NaOH) / n(Ag)=7, and dissolve them separately in 50 mL of deionized water. Heat the K2S2O8 and NaOH solutions to 60 °C and mix them. Add the material calcined at 700 °C in small amounts several times while stirring, and allow the oxidation reaction to proceed for 75 min. After the reaction is complete, filter the mixture and wash it 2-3 times with deionized water. Finally, dry it in a 60 °C oven for 6 h to obtain the AgO / MgO / Mg(OH)2 composite material.

[0032] Step 3: Using the fluorinated modified SiO2 nanoparticles obtained in Step 1 and the AgO / MgO / Mg(OH)2 composite material obtained in Step 2 as dual fillers, weigh and mix the AgO / MgO / Mg(OH)2 composite material (1.5wt%), the fluorinated modified SiO2 nanoparticles (8.5wt%), and the remaining epoxy resin powder to a mass of 20g. Then, ball mill the mixed powder in a horizontal ball mill at 300r / min for 5h to obtain epoxy resin-based powder containing dual fillers.

[0033] Step 4: Place the Q235 steel in a sandblasting machine and use compressed air at 0.6 MPa to sandblast at a distance of approximately 30 mm from the sample. Simultaneously, tilt the sample at a 30° angle to avoid localized damage to the substrate and to prevent sandblasting dead zones. The impact of the sand particles on the surface removes grease, dirt, oxide layers, and rust, thereby improving coating adhesion.

[0034] Step 5: Place the sandblasted Q235 steel specimen in an oven and preheat it to 220℃. Using 0.8 MPa compressed air, electrostatically spray epoxy resin-based powder containing double fillers onto the surface of the Q235 steel specimen. After spraying, place the specimen in an oven and keep it at 220℃ for 30 minutes, then cool it to room temperature with the oven.

[0035] Example 3 This invention discloses a method for preparing an epoxy resin-based superhydrophobic, corrosion-resistant, and antifouling coating using a dual-filler configuration, which specifically includes the following steps: Step 1: A certain volume of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was measured and added to anhydrous ethanol and mixed thoroughly to prepare 50 mL of a 10.0% (v / v) perfluorodecyltriethoxysilane modification solution. Then, 5 g of 30 nm hydrophobic SiO2 nanoparticles were added, and the mixture was magnetically stirred for 5 h, centrifuged, and dried to obtain fluorinated modified SiO2 nanoparticles.

[0036] Step 2: Prepare 50 mL of 0.37 mol / L AgNO3 solution and 25 mL of 0.74 mol / L NaOH solution. Add the NaOH solution dropwise to the AgNO3 solution under magnetic stirring, forming a brownish-yellow precipitate. Then, add 5 mol / L ammonia solution until the precipitate is completely dissolved, obtaining a silver ammonia solution. Next, add 2.0 g of commercially available MgO nanoparticles with a particle size of 30 nm to the silver ammonia solution and stir for 2 h. Separate reaction product 1 and the filtrate by vacuum filtration. Determine the silver ion content in the filtrate using the Volhard method to determine the amount of silver ions adsorbed by the MgO nanoparticles. Weigh out an amount of NaCl equal to the molar amount of adsorbed silver ions to prepare a 100 mL solution. Add the separated reaction product 1 to the NaCl solution and stir for 30 min. Vacuum filter to obtain reaction product 2, wash 2-3 times with deionized water, dry at 60℃ for 6 h, and then heat to 700℃ at a rate of 2℃ / min and hold for 8 h. Based on the silver ion adsorption capacity determined above, weigh out the corresponding amounts of K2S2O8 and NaOH according to n(K2S2O8) / n(Ag)=3 and n(NaOH) / n(Ag)=7, and dissolve them separately in 50 mL of deionized water. Heat the K2S2O8 and NaOH solutions to 60 °C and mix them. Add the material calcined at 700 °C in small amounts several times while stirring, and allow the oxidation reaction to proceed for 75 min. After the reaction is complete, filter the mixture and wash it 2-3 times with deionized water. Finally, dry it in a 60 °C oven for 6 h to obtain the AgO / MgO / Mg(OH)2 composite material.

[0037] Step 3: Using the fluorinated modified SiO2 nanoparticles obtained in Step 1 and the AgO / MgO / Mg(OH)2 composite material obtained in Step 2 as dual fillers, weigh and mix them according to the following ratios: AgO / MgO / Mg(OH)2 composite material mass ratio 1.5wt%, fluorinated modified SiO2 nanoparticle mass ratio 7.5wt%, and the remainder being epoxy resin powder, to make a mass of 20g. The mixed powder is ball-milled in a horizontal ball mill at a speed of 300r / min for 6h to obtain epoxy resin-based powder containing dual fillers.

[0038] Step 4: Place the Q235 steel in a sandblasting machine and use compressed air at 0.5 MPa to sandblast at a distance of approximately 25 mm from the sample. Simultaneously, tilt the sample at a 30° angle to avoid localized damage to the substrate and to prevent sandblasting dead zones. The impact of the sand particles on the surface removes grease, dirt, oxide layers, and rust, thereby improving coating adhesion.

[0039] Step 5: Place the sandblasted Q235 steel specimen in an oven and preheat it to 200℃. Using 0.8 MPa compressed air, electrostatically spray epoxy resin-based powder containing double fillers onto the surface of the preheated Q235 steel specimen. After spraying, place the specimen in an oven and keep it at 200℃ for 25 minutes, then cool it to room temperature with the oven.

[0040] Figures 1(a), 1(b), and 1(c) show the water contact angles of the epoxy resin-based superhydrophobic, corrosion-resistant, and antifouling coatings constructed using dual fillers, as described in Examples 1, 2, and 3 of the present invention. As shown in Figure 1(a), the epoxy resin-based coating prepared with an AgO / MgO / Mg(OH)2 composite material mass ratio of 1.5 wt% and a 7.5% fluorinated modified SiO2 nanoparticle mass ratio of 10 wt% has a water contact angle of 139.7°, exhibiting high hydrophobicity but not reaching superhydrophobicity. As shown in Figure 1(b), the epoxy resin-based coating prepared with an AgO / MgO / Mg(OH)2 composite material mass ratio of 1.5 wt% and a 10.0% fluorinated modified SiO2 nanoparticle mass ratio of 8.5 wt% has a water contact angle of 153.7°, achieving superhydrophobicity and realizing both water repellency and self-cleaning properties. As shown in Figure 1(c), the epoxy resin-based coating prepared with an AgO / MgO / Mg(OH)2 composite material of 1.5 wt% and a 10.0% fluorinated modified SiO2 nanoparticle mass ratio of 7.5 wt% exhibits a water contact angle of 141.7°, demonstrating high hydrophobicity, but not reaching superhydrophobicity. These results indicate that the optimal mass ratio of the two fillers and the low surface energy modifier concentration are required to achieve superhydrophobic properties in the coating.

[0041] Figures 2(a), 2(b), and 2(c) show the three-dimensional morphology and surface roughness of the epoxy resin-based superhydrophobic, corrosion-resistant, and antifouling coatings prepared using dual fillers in Examples 1, 2, and 3 of the present invention, obtained using laser confocal scanning microscopy. As shown in Figure 2(a), the epoxy resin-based coating prepared with an AgO / MgO / Mg(OH)2 composite material mass ratio of 1.5 wt% and a 7.5% fluorinated modified SiO2 nanoparticle mass ratio of 10 wt% exhibits fewer micro / nano structures and lower surface roughness. The epoxy resin-based coating prepared with an AgO / MgO / Mg(OH)2 composite material mass ratio of 1.5 wt% and a 10.0% fluorinated modified SiO2 nanoparticle mass ratio of 8.5 wt% shows a more pronounced micro / nano structure that is distributed throughout the entire coating surface, resulting in higher surface roughness (Figure 2(b)). The epoxy resin-based coating prepared with AgO / MgO / Mg(OH)2 composite material at a mass ratio of 1.5wt% and 10.0% fluorinated modified SiO2 nanoparticles at a mass ratio of 7.5wt% still has obvious surface micro / nano structures and high surface roughness, but the distribution of micro / nano structures is not as good as the coating prepared in Example 2 (Figure 2(c)).

[0042] Figure 3 These are the potentiodynamic polarization curves of a pure epoxy resin coating (EP), an epoxy resin-based coating with only 1.5 wt% AgO / MgO / Mg(OH)2 composite material, and epoxy resin-based coatings prepared with different concentrations of fluorinated silane treated with SiO2 nanoparticles at a mass addition of 10 wt% and AgO / MgO / Mg(OH)2 composite material at a mass addition of 1.5 wt%. (The text repeats itself here.) Figure 3 It can be seen that (EP is a pure epoxy resin coating, and EPA is an epoxy resin-based coating with only 1.5wt% AgO / MgO / Mg(OH)2 composite material added), compared with the pure epoxy resin coating (EP), the self-corrosion potential of the double-filler epoxy resin-based coatings with SiO2 nanoparticles treated with 5.0%, 7.5%, and 10.0% fluorinated silane shifts positively, and the corrosion current density decreases; while the self-corrosion potential of the double-filler epoxy resin-based coating with SiO2 nanoparticles treated with 2.5% fluorinated silane shifts negatively, and the corrosion current density increases. This indicates that the introduction of appropriate amounts of fluorinated silane-modified SiO2 nanoparticles and AgO / MgO / Mg(OH)2 composite material can improve the corrosion resistance of epoxy resin coatings, but when the modification concentration is too low, the compatibility between the filler and the resin deteriorates, and the corrosion resistance of the coating is lower than that of the pure epoxy resin coating.

[0043] Example 4 Compared with Example 1, the ball milling time in step 3 is 3 hours, and the remaining steps are the same as in Example 1.

[0044] Example 5 Compared with Example 1, in step 4, the pressure of the compressed air is 0.5 MPa, and the remaining steps are the same as in Example 1.

[0045] Example 6 Compared with Example 1, in step 5, the oven preheating temperature is 190°C.

[0046] The present invention provides a method for preparing an epoxy resin-based superhydrophobic, corrosion-resistant, and antifouling coating using dual fillers. The method uses a sheet-like AgO / MgO / Mg(OH)2 composite material with a length of approximately 200 nm and fluorinated SiO2 nanoparticles with a particle size of approximately 30 nm as dual fillers. The dual fillers are ball-milled with epoxy resin powder to uniformly disperse the dual fillers in the epoxy resin. Then, the electrostatic field of an electrostatic spraying method is used to distribute the dual fillers with different electrical properties and particle size differences at the top and bottom of the coating, which is beneficial for obtaining more surface micro- and nano-structures, thereby preparing an epoxy resin-based superhydrophobic coating on the surface of Q235 steel. Compared to antifouling coatings prepared with MgO-modified AgO composite antibacterial agents, the epoxy resin-based superhydrophobic coating prepared by this method has a higher water contact angle, achieving both water repellency and self-cleaning properties. This solves the aesthetic problem of killed bacteria adhering to the antifouling coating surface. Furthermore, due to the synergistic effect of water repellency, this coating exhibits more durable corrosion resistance and antifouling performance, addressing the issues of poor durability and inability to inhibit biofouling in traditional epoxy resin protective coatings. Therefore, the epoxy resin-based superhydrophobic corrosion-resistant and antifouling coating prepared by this method, utilizing dual fillers, can achieve durable corrosion resistance and antifouling through its water repellency and self-cleaning properties, showing potential application prospects in the field of corrosion and antifouling protection for marine equipment materials.

[0047] This invention employs a low-cost AgO / MgO / Mg(OH)2 composite material with strong antibacterial activity and highly wear-resistant SiO2 nanoparticles as dual fillers. A low surface energy modifier reduces the surface energy of the SiO2 nanoparticles. The particle size difference between the dual fillers is utilized to construct micro / nano structures on the coating surface, thus preparing a superhydrophobic epoxy resin-based corrosion-resistant and antifouling coating. Firstly, the coating's water-repellent and self-cleaning properties achieve corrosion protection and prevent biofouling. Secondly, the dual fillers fill the pores in the coating, further enhancing its physical barrier properties. Finally, the strong antibacterial activity of the fillers kills bacteria adhering to the coating surface, preventing biofilm formation. The self-cleaning properties of the superhydrophobic coating remove surface-adhered bacteria, improving the coating's aesthetics. Ultimately, this achieves the epoxy resin coating's corrosion resistance, durability, and antifouling properties.

Claims

1. A method for preparing an epoxy resin-based superhydrophobic coating, characterized in that: Specifically, the steps include the following: Step 1: Prepare fluorinated modified SiO2 nanoparticles; Step 2: Prepare AgO / MgO / Mg(OH)2 composite material; Step 3: Using the fluorinated modified SiO2 nanoparticles obtained in Step 1 and the AgO / MgO / Mg(OH)2 composite material obtained in Step 2 as dual fillers, prepare epoxy resin-based powder containing dual fillers. Step 4: Sandblast the surface of the steel. Step 5: Place the sandblasted steel in an oven for preheating. Use compressed air to electrostatically spray epoxy resin-based powder containing double fillers onto the surface of the preheated steel. After spraying, place the steel in the oven for heat preservation and cool it to room temperature with the furnace.

2. The method for preparing the epoxy resin-based superhydrophobic coating according to claim 1, characterized in that: The specific process of step 1 is as follows: 1H,1H,2H,2H-perfluorodecyltriethoxysilane is added to anhydrous ethanol and mixed evenly to prepare a perfluorodecyltriethoxysilane modification solution. Then, gas-phase hydrophobic SiO2 nanoparticles are added, and after magnetic stirring, centrifugation and drying are performed to obtain fluorinated modified SiO2 nanoparticles.

3. The method for preparing the epoxy resin-based superhydrophobic coating according to claim 2, characterized in that: In step 1, the volume fraction of the perfluorodecyltriethoxysilane modification solution is 2.5% to 12.5%.

4. The method for preparing an epoxy resin-based superhydrophobic coating according to claim 2, characterized in that: The specific process of step 3 is as follows: using the fluorinated modified SiO2 nanoparticles obtained in step 1 and the AgO / MgO / Mg(OH)2 composite material obtained in step 2 as dual fillers, the AgO / MgO / Mg(OH)2 composite material, fluorinated modified SiO2 nanoparticles and epoxy resin powder are mixed, and the mixed powder is ball-milled on a horizontal ball mill to obtain epoxy resin-based powder containing dual fillers.

5. The method for preparing an epoxy resin-based superhydrophobic coating according to claim 4, characterized in that: In step 3, the mass percentage of fluorinated modified SiO2 nanoparticles in the mixed powder is 2.5–10 wt%.

6. The method for preparing an epoxy resin-based superhydrophobic coating according to claim 4, characterized in that: In step 3, the ball milling time is 2 to 6 hours.

7. The method for preparing an epoxy resin-based superhydrophobic coating according to claim 4, characterized in that: The specific process of step 4 is as follows: place the steel in a sandblasting machine and use compressed air of 0.4 to 0.6 MPa to sandblast at a distance of about 20 to 30 mm from the sample.

8. The method for preparing the epoxy resin-based superhydrophobic coating according to claim 4, characterized in that: The specific process of step 5 is as follows: the sandblasted steel is placed in an oven and preheated to 180-260°C. Using compressed air, epoxy resin-based powder containing double fillers is electrostatically sprayed onto the surface of the preheated steel. After the spraying is completed, the sample is placed in an oven and kept warm for 20-30 minutes before being cooled to room temperature with the oven.

9. An epoxy resin-based superhydrophobic coating, prepared by the method for preparing an epoxy resin-based superhydrophobic coating as described in any one of claims 1 to 8.

10. Application of epoxy resin-based superhydrophobic coatings in corrosion and fouling prevention.

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