An antibacterial composite coating and a preparation method and application thereof

Abstract

The application belongs to the field of antibacterial coating, and particularly relates to an antibacterial composite coating and a preparation method and application thereof. The application first adopts an atmospheric plasma spraying technology to prepare a dense titanium coating on the surface of a metal substrate, then adopts a hydrothermal reaction method to convert the titanium coating into a barium titanate coating, and finally uses an in-situ chemical deposition technology to prepare a layer of polypyrrole on the surface of the barium titanate coating to obtain a polypyrrole-coated barium titanate nanostructure antibacterial composite coating. The antibacterial composite coating has high photocatalytic antibacterial effect, can effectively remove organic substances and bacteria, and prevent the organic substances and bacteria from adhering to the surface of equipment.

Description

Technical Field

[0001] This invention belongs to the field of antibacterial coatings, specifically relating to an antibacterial composite coating, its preparation method, and its application. Background Technology

[0002] Offshore wind power is a clean and renewable energy generation technology that effectively captures wind energy and converts it into electricity by installing wind turbines at sea. However, due to long-term operation in the marine environment, these devices are susceptible to marine organism attachment and corrosion, which can reduce their performance and lifespan. Furthermore, the surface of offshore wind power equipment can become a breeding ground for bacteria, algae, and other microorganisms, which can lead to equipment damage, biofouling, and environmental problems.

[0003] Photocatalytic reactions typically involve the use of semiconductor materials such as titanium dioxide, which can generate electron-hole pairs under the influence of light, thereby initiating redox reactions that decompose organic matter into harmless substances. Photocatalysis is a technology that degrades or oxidizes organic and inorganic substances by using light energy to excite reactions on the surface of a catalyst. Photocatalytic antibacterial technology typically involves combining antibacterial materials with photocatalysts to prepare photocatalytic antibacterial coatings or materials. These coatings can be applied in various fields, including medical devices, food packaging, water treatment, building materials, and air purification.

[0004] To address the aforementioned issues with offshore wind turbines, a photocatalytic antibacterial coating technology has been developed for their surfaces. This technology combines the properties of photocatalysis and antibacterial materials to protect the turbine surfaces from attached organisms. On offshore wind turbines, photocatalysis can be used to remove organic matter and bacteria, preventing their adhesion to the surface. Photocatalytic antibacterial technology offers multiple advantages, including high antibacterial efficiency, durability, reusability, no need for chemical disinfectants, and no harmful byproducts. This photocatalytic antibacterial coating technology for offshore wind turbines represents a key innovation that promises to improve the performance and lifespan of offshore wind turbines, reduce maintenance costs, and minimize negative impacts on the marine ecosystem. However, current photocatalytic antibacterial coatings for offshore wind turbines still suffer from poor photocatalytic antibacterial efficacy and require stringent and complex manufacturing processes. Summary of the Invention

[0005] In view of the problems of poor photocatalytic antibacterial effect and harsh and complex preparation process of the photocatalytic antibacterial coatings involved in the above-mentioned prior art, the present invention will provide an antibacterial composite coating, its preparation method and application.

[0006] To achieve the above objectives, the following technical solutions are specifically included:

[0007] A method for preparing an antibacterial composite coating includes the following steps:

[0008] (1) Titanium powder is sprayed and deposited onto the surface of a metal substrate by atmospheric plasma method to obtain a titanium coating;

[0009] (2) The titanium coating is placed in an alkaline solution for a hydrothermal reaction, followed by cleaning;

[0010] (3) Add barium hydroxide solution to carry out hydrothermal reaction to obtain barium titanate coating;

[0011] (4) The barium titanate coating is placed in a polyvinyl alcohol solution, and then pyrrole solution and ferric chloride are added in sequence to react. After cleaning, the antibacterial composite coating is obtained.

[0012] This invention first uses atmospheric plasma spraying technology to prepare a dense titanium coating on the surface of a metal substrate. Then, a hydrothermal reaction method is used to transform the titanium coating into a barium titanate coating. Finally, an in-situ chemical deposition technique is used to prepare a polypyrrole layer on the surface of the barium titanate coating, resulting in a polypyrrole-coated barium titanate nanostructure antibacterial composite coating. The polypyrrole-coated barium titanate nanostructure achieves highly efficient inhibition and killing of bacteria and other microorganisms under light conditions by improving photocatalytic performance, enhancing conductivity, and stability. The preparation process of this antibacterial composite coating is relatively simple, with high photocatalytic antibacterial effect, effectively removing organic matter and bacteria and preventing them from adhering to the surface of equipment.

[0013] Preferably, in step (1), the atmospheric plasma method includes the following process parameters: spraying power of 10-30kW, spraying distance of 50-150mm, powder feeding rate of 10-20g / min, spray gun moving speed of 300-500mm / s, main gas is argon with a flow rate of 50-70L / min, auxiliary gas is helium with a flow rate of 10-20L / min.

[0014] Preferably, the thickness of the titanium coating is 50-100 μm.

[0015] Preferably, in step (1), the titanium coating is further subjected to pickling, wherein the acid in the pickling is a mixed solution of nitric acid and hydrofluoric acid, the mass concentration ratio of nitric acid to hydrofluoric acid is 1:(1-3), and the pickling time is 5-20 min.

[0016] Preferably, in step (1), at least one of copper plate, stainless steel, and aluminum plate is used.

[0017] Preferably, in step (2), the alkaline solution includes at least one of sodium hydroxide solution and potassium hydroxide solution, and the concentration of the alkaline solution is 5-12 mol / L.

[0018] Preferably, in step (2), the temperature of the hydrothermal reaction is 80-120℃, and the time of the hydrothermal reaction is 20-30h.

[0019] Preferably, in step (3), the concentration of the barium hydroxide solution is 0.01-1 mol / L.

[0020] More preferably, in step (3), the concentration of the barium hydroxide solution is 0.02-0.2 mol / L.

[0021] Preferably, in step (3), the temperature of the hydrothermal reaction is 180-250℃, and the time of the hydrothermal reaction is 5-10h.

[0022] Preferably, in step (4), the reaction temperature is 0-4℃ and the reaction time is 0.5-3h.

[0023] Preferably, in step (4), the concentration of the polyvinyl alcohol solution is 10-15 g / L.

[0024] Preferably, in step (4), the concentration of the pyrrole solution is 0.005-1 mol / L.

[0025] More preferably, in step (4), the concentration of the pyrrole solution is 0.01-0.5 mol / L.

[0026] Preferably, in step (4), the molar ratio of pyrrole to ferric chloride in the pyrrole solution is 1:(0.5-1.5).

[0027] Preferably, the cleaning in steps (2) and (4) is washing with water and soaking, and the soaking time is 10-30 hours.

[0028] This invention also provides an application of the aforementioned antibacterial composite coating in the manufacture of marine wind power equipment. This antibacterial coating can be applied to the surface of the marine wind power equipment to enhance its biological protection. It can effectively reduce the attachment of marine organisms such as bacteria, algae, and other microorganisms, thereby mitigating the negative impact on the marine ecosystem. This not only helps maintain the performance of the equipment and extend its service life, but also reduces maintenance costs, thereby improving the reliability and economic benefits of the marine wind power equipment. Furthermore, maintaining the cleanliness of the equipment surface helps reduce the use of chemical disinfectants, lowers the risk of environmental pollution, and makes the marine environment cleaner and more sustainable.

[0029] Compared with the prior art, the present invention has the following beneficial effects: the antibacterial composite coating of the present invention has a high photocatalytic antibacterial effect, which can effectively remove organic matter and bacteria and prevent them from adhering to the surface of the equipment. In particular, under infrared light irradiation, the antibacterial rate of the coating can reach 99%. Attached Figure Description

[0030] Figure 1 This is a scanning electron microscope image of the barium titanate / polypyrrole nanostructured antibacterial composite coating of Example 1.

[0031] Figure 2 The image shows the energy spectrum of the barium titanate / polypyrrole nanostructure antibacterial composite coating in Example 1.

[0032] Figure 3 This is a scanning electron microscope image of the barium titanate / polypyrrole nanostructured antibacterial composite coating from Example 2.

[0033] Figure 4 This is a scanning electron microscope image of the barium titanate / polypyrrole nanostructured antibacterial composite coating of Example 3.

[0034] Figure 5 The image shows the photocatalytic antibacterial effect of the barium titanate / polypyrrole nanostructure antibacterial composite coating in Example 1.

[0035] Figure 6 This image shows the results of staining Staphylococcus aureus with a barium titanate / polypyrrole nanostructure antibacterial composite coating as described in Example 1. Detailed Implementation

[0036] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0037] Example 1

[0038] (1) Titanium powder (commercially available) was sprayed and deposited onto the surface of a metal substrate (stainless steel, the same below) by atmospheric plasma method to obtain a titanium coating. When preparing the titanium coating by spraying and depositing using atmospheric plasma spraying equipment, the following parameters were set: spraying power 20kW, spraying distance 100mm, powder feeding rate 15g / min, spray gun moving speed 400mm / s, one spraying, coating thickness 50-100μm, main gas Ar with a flow rate of 60L / min, auxiliary gas He with a flow rate of 15L / min;

[0039] (2) Mix 0.68wt.% HNO3 and 0.4wt.% HF in a volume ratio of 1:2, then immerse the titanium coating obtained in step (1) along with the loaded metal substrate in the above mixed acid solution, stir and react for 10 minutes to remove the oxide layer on the titanium surface, then rinse with deionized water to remove the residual acid, and finally dry at room temperature for later use.

[0040] (3) Prepare an 8 mol / L NaOH solution, add the titanium coating along with its loaded metal substrate and NaOH solution into the inner liner of the hydrothermal reactor (fill to 60% of the reactor volume, similar cases below), then place the inner liner into the reactor, set the hydrothermal reaction parameters to 100℃, keep it at that temperature for 24 hours, then allow it to cool naturally, take out the sample, wash it with deionized water and soak it for 24 hours to remove residual impurities on the surface; then rinse the inner liner with deionized water and dry it for later use.

[0041] (4) Prepare a 0.05 mol / L Ba(OH)2 solution, place the product obtained in step (3) above into a clean reaction vessel inner liner, add the prepared Ba(OH)2 solution, then put the inner liner into the reaction vessel, set the hydrothermal reaction parameters to 210℃, keep it warm for 8 hours, then cool it in the air, take out the sample and soak it in deionized water for 24 hours to obtain a metal substrate loaded with barium titanate coating;

[0042] (5) The metal substrate loaded with barium titanate coating was immersed in a beaker of 12 g / L polyvinyl alcohol solution. The polyvinyl alcohol guides the polymerization of pyrrole on the surface. The average Mw of the polyvinyl alcohol is 130,000. The polyvinyl alcohol solution should be enough to submerge the sheet. 20 ml of the solution was used and placed in a stirring water bath with an ice bath. When the water temperature dropped to the range of 0-4℃, 0.1 mol / L pyrrole monomer solution was added dropwise. Stirring was continued for 30 minutes under ice bath conditions. Then, an appropriate amount of ferric chloride hexahydrate solid was added as an oxidant, and the molar ratio of ferric chloride to pyrrole monomer was 1:1. Stirring was continued in an ice bath for 2 hours. After the reaction was completed, the sample was soaked and cleaned with deionized water for 24 hours, during which the water was changed three times. Finally, the sample was dried with cold air on a clean bench to obtain a metal substrate containing a barium titanate / polypyrrole nanostructure antibacterial composite coating.

[0043] Example 2

[0044] (1) Titanium powder was deposited onto the surface of a metal substrate by atmospheric plasma spraying to obtain a titanium coating. The following parameters were set when preparing the titanium coating using atmospheric plasma spraying equipment: spraying power 20kW, spraying distance 100mm, powder feed rate 15g / min, and spray gun moving speed 400mm / s. The main gas was Ar with a flow rate of 60L / min; the auxiliary gas was He with a flow rate of 15L / min.

[0045] (2) Prepare a mixed acid aqueous solution by mixing 0.68wt.% HNO3 and 0.4wt.% HF in a volume ratio of 1:2. Then immerse the titanium coating obtained in step (1) along with the loaded metal substrate in the above mixed acid solution and stir for 10 minutes to remove the oxide layer on the titanium surface. Then rinse with deionized water to remove the residual acid solution and finally dry at room temperature for later use.

[0046] (3) Prepare an 8 mol / L NaOH solution, add the titanium coating along with its loaded metal substrate and NaOH solution into the inner liner of the hydrothermal reactor, then place the inner liner into the reactor, set the hydrothermal reaction parameters to 100℃, keep it at that temperature for 24 hours, and then allow it to cool naturally. Take out the sample, wash it with deionized water and soak it for 24 hours to remove residual impurities on the surface; then rinse the inner liner with deionized water and dry it for later use.

[0047] (4) Prepare a 0.02 mol / L Ba(OH)2 solution, place the product obtained in step (3) above into a clean reaction vessel inner liner, add the prepared Ba(OH)2 solution, then put the inner liner into the reaction vessel, set the hydrothermal reaction parameters to 210℃, keep it warm for 8 hours, then cool it in the air, take out the sample and soak it in deionized water for 24 hours to obtain a metal substrate loaded with barium titanate coating;

[0048] (5) The metal substrate loaded with barium titanate coating was immersed in a beaker of 12 g / L polyvinyl alcohol solution. The polyvinyl alcohol guides the polymerization of pyrrole on the surface. The average Mw of the polyvinyl alcohol is 130,000. The polyvinyl alcohol solution should be enough to submerge the sheet. 20 ml of the solution was used and placed in a stirring water bath with an ice bath. When the water temperature dropped to the range of 0-4℃, 0.1 mol / L pyrrole monomer solution was added dropwise. Stirring was continued for 120 minutes under ice bath conditions. Then, an appropriate amount of ferric chloride hexahydrate solid was added as an oxidant, and the molar ratio of ferric chloride to pyrrole monomer was 1:1. Stirring was continued for 2 hours under ice bath conditions. After the reaction was completed, the sample was soaked and cleaned with deionized water for 24 hours, during which the water was changed three times. Finally, the sample was dried with cold air on a clean bench to obtain a metal substrate containing a barium titanate / polypyrrole nanostructure antibacterial composite coating.

[0049] Example 3

[0050] (1) Titanium powder was deposited onto the surface of a metal substrate by atmospheric plasma spraying to obtain a titanium coating. The following parameters were set when preparing the titanium coating using atmospheric plasma spraying equipment: spraying power 20kW, spraying distance 100mm, powder feed rate 15g / min, and spray gun moving speed 400mm / s. The main gas was Ar with a flow rate of 60L / min; the auxiliary gas was He with a flow rate of 15L / min.

[0051] (2) Prepare a mixed acid aqueous solution by mixing 0.68wt.% HNO3 and 0.4wt.% HF in a volume ratio of 1:2. Then immerse the titanium coating obtained in step (1) along with the loaded metal substrate in the above mixed acid solution and stir for 10 minutes to remove the oxide layer on the titanium surface. Then rinse with deionized water to remove the residual acid solution and finally dry at room temperature for later use.

[0052] (3) Prepare an 8 mol / L NaOH solution, add the titanium coating along with its loaded metal substrate and NaOH solution into the inner liner of the hydrothermal reactor, then place the inner liner into the reactor, set the hydrothermal reaction parameters to 100℃, keep it at that temperature for 24 hours, and then allow it to cool naturally. Take out the sample, wash it with deionized water and soak it for 24 hours to remove residual impurities on the surface; then rinse the inner liner with deionized water and dry it for later use.

[0053] (4) Prepare a 0.2 mol / L Ba(OH)2 solution, place the product obtained in step (3) above into a clean reaction vessel inner liner, add the prepared Ba(OH)2 solution, then put the inner liner into the reaction vessel, set the hydrothermal reaction parameters to 210℃, keep it warm for 8 hours, then cool it in the air, take out the sample and soak it in deionized water for 24 hours to obtain a metal substrate loaded with barium titanate coating;

[0054] (5) The metal substrate loaded with barium titanate coating was immersed in a beaker of 12 g / L polyvinyl alcohol solution. The polyvinyl alcohol guides the polymerization of pyrrole on the surface. The average Mw of the polyvinyl alcohol is 130,000. The polyvinyl alcohol solution should be enough to submerge the sheet. 20 ml of the solution was used and placed in a stirring water bath with an ice bath. When the water temperature dropped to the range of 0-4℃, 0.5 mol / L pyrrole monomer solution was added dropwise. Stirring was continued for 20 minutes under ice bath conditions. Then, an appropriate amount of ferric chloride hexahydrate solid was added as an oxidant, and the molar ratio of ferric chloride to pyrrole monomer was 1:1. Stirring was continued for 2 hours under ice bath conditions. After the reaction was completed, the sample was soaked and cleaned with deionized water for 24 hours, during which the water was changed three times. Finally, the sample was dried with cold air on a clean bench to obtain a metal substrate containing a barium titanate / polypyrrole nanostructure antibacterial composite coating.

[0055] The barium titanate / polypyrrole nanostructured antibacterial composite coatings prepared in Examples 1-3 were characterized by scanning electron microscopy, and the results are shown in the appendix. Figure 1-4 , including Figure 1 , 3 -4 It can be observed that the antibacterial composite coating prepared by the method of the present invention is a dense nanostructure coating. In Examples 1-3, the reaction rate was controlled by changing the concentrations of barium hydroxide and pyrrole monomers and the reaction time. The results show that the surface of each coating contains polypyrrole and barium titanate, but the degree of density varies. (See Appendix...) Figure 2 It can be seen that the coating clearly contains N and C elements from polypyrrole, and Ti, Ba, and O elements from barium titanate.

[0056] The photoresponsive antibacterial properties of the coating in Example 1 were evaluated using a Gram-positive Staphylococcus aureus strain. The specific procedures are as follows:

[0057] (1) Reagent preparation, bacterial recovery and culture: Liquid culture medium and solid agar culture dishes were prepared using nutrient broth and nutrient agar, respectively. Materials and ultra-clean bench were sterilized. The bacterial cryopreservation solution was taken out from the -20℃ freezer, shaken for 1 minute, diluted appropriately, and then placed in a shaker for several hours.

[0058] (2) In vitro antibacterial efficiency test:

[0059] The Staphylococcus aureus bacterial stock solution was serially diluted, and 500 μL of each solution was added to the wells of a 48-well plate. The absorbance at 600 nm was measured using a multi-mode microplate reader, and the bacterial concentration was determined by photoelectric turbidimetry. The solution was then diluted to a fixed fold, and 10 μL of [unspecified ingredient] was added to each well. 6 CPU / L bacterial solution.

[0060] The composite coating samples prepared above were divided into a dark group and a light-illuminated group. Both groups were co-cultured in a 37℃ biochemical incubator for 3 hours. The light-illuminated group was then subjected to near-infrared light treatment with the following parameters: wavelength 808 nm, power 1.0 W·cm⁻¹. -2 The bacterial suspension was exposed to light for 10 minutes. Afterward, the suspension was transferred to another well plate, diluted appropriately, and 50 μL of the diluted suspension was evenly spread onto an agar plate using a disposable bacterial spreader. The plate was then incubated at 37°C for an appropriate time. The colony count (N) on the solid agar plate was photographed and recorded. Four replicates were prepared for each sample group. The antibacterial efficiency was calculated using the following formula:

[0061]

[0062] The test results are attached. Figure 5 As shown.

[0063] Bacterial live / dead staining characterization: Bacteria were stained using the LIVE / DEAD BacLight bacterial activity assay kit. The specific procedure was as follows: First, the staining solution was prepared by mixing SYTO9 staining solution, PI staining solution, and PBS in a 1:1:200 ratio to prepare an appropriate volume of the staining solution, and stored in the dark. Next, the samples were treated: 48-well plates were divided into dark and light groups, with bacterial inoculation parameters strictly consistent with the antibacterial efficiency test described above. After co-culturing the samples in a 37°C biochemical incubator for 3 hours, the light group underwent near-infrared light treatment (808nm laser, 1.0W·cm⁻¹). -2 (Illumination time 10 min). After thoroughly mixing the bacteria in the bacterial plate, transfer 100 μL to another well, add 80 μL of the prepared staining solution, incubate in the dark for an appropriate time, and then observe the bacterial staining under an inverted fluorescence microscope. The test results are attached. Figure 6 As shown.

[0064] Combined with appendix Figure 5-6 It is known that under infrared light irradiation, the antibacterial rate of the coating can reach 99.82%, and almost all Staphylococcus aureus adhering to the coating surface dies under infrared light irradiation. However, without the polypyrrole coating, pure barium titanate does not respond to infrared light, and its antibacterial effect is poor or even non-existent. Therefore, the barium titanate / polypyrrole nanostructure antibacterial composite coating of the present invention has excellent photocatalytic antibacterial properties and is very suitable for application on the surface of marine wind power equipment.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an antibacterial composite coating, characterized in that, Includes the following steps: (1) Titanium powder is sprayed and deposited onto the surface of a metal substrate by atmospheric plasma method to obtain a titanium coating; (2) The titanium coating is placed in an alkaline solution for a hydrothermal reaction, followed by cleaning; (3) Add barium hydroxide solution to carry out a hydrothermal reaction to obtain a barium titanate coating; the temperature of the hydrothermal reaction is 180-250℃. (4) The barium titanate coating is placed in a polyvinyl alcohol solution, and then pyrrole solution and ferric chloride are added in sequence to react. After cleaning, the antibacterial composite coating is obtained. The antibacterial composite coating contains barium titanate and polypyrrole.

2. The method for preparing the antibacterial composite coating as described in claim 1, characterized in that, In step (1), the atmospheric plasma method includes the following process parameters: spraying power of 10-30kW, spraying distance of 50-150mm, powder feeding rate of 10-20g / min, spray gun moving speed of 300-500mm / s, main gas is argon with a flow rate of 50-70L / min, auxiliary gas is helium with a flow rate of 10-20L / min.

3. The method for preparing the antibacterial composite coating as described in claim 1, characterized in that, In step (2), the alkaline solution includes at least one of sodium hydroxide solution and potassium hydroxide solution, and the concentration of the alkaline solution is 5-12 mol / L.

4. The method for preparing the antibacterial composite coating as described in claim 1, characterized in that, In step (2), the temperature of the hydrothermal reaction is 80-120℃, and the time of the hydrothermal reaction is 20-30h.

5. The method for preparing the antibacterial composite coating as described in claim 1, characterized in that, In step (3), the concentration of the barium hydroxide solution is 0.01-1 mol / L.

6. The method for preparing the antibacterial composite coating as described in claim 1, characterized in that, In step (3), the hydrothermal reaction takes 5-10 hours.

7. The method for preparing the antibacterial composite coating as described in claim 1, characterized in that, In step (4), the reaction temperature is 0-4℃ and the reaction time is 0.5-3h.

8. The method for preparing the antibacterial composite coating as described in claim 1, characterized in that, Includes at least one of the following: In step (4), the concentration of the polyvinyl alcohol solution is 10-15 g / L; In step (4), the concentration of the pyrrole solution is 0.005-1 mol / L; In step (4), the molar ratio of pyrrole to ferric chloride in the pyrrole solution is 1:(0.5-1.5); The cleaning described in steps (2) and (4) is washing with water and soaking, and the soaking time is 10-30 hours; In step (1), the titanium coating is also pickled. The acid used in the pickling is a mixed solution of nitric acid and hydrofluoric acid, and the mass concentration ratio of nitric acid to hydrofluoric acid is 1:(1-3). The pickling time is 5-20 min.

9. An antibacterial composite coating prepared by the method of any one of claims 1 to 8.

10. The application of the antibacterial composite coating of claim 9 in the preparation of marine wind power equipment.

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