An antibacterial composite coating and a preparation method and application thereof

Abstract

The application relates to an antibacterial composite coating as well as a preparation method and application thereof, and belongs to the technical field of antibacterial coatings. The antibacterial composite coating comprises a primer and a topcoat, the topcoat comprises nanoparticles, a zwitterionic polymer and a binder, the nanoparticles comprise barium titanate, and a polypyrrole layer and a polydopamine layer are sequentially coated on the surface of the barium titanate. The antibacterial composite coating combines photocatalytic antibacterial and zwitterionic anti-adhesion two functional materials, and through organic combination of the structures, diurnal continuous antimicrobial protection is realized. The development of the antibacterial composite coating can not only significantly improve the service life of marine wind power equipment, but also provides important technical support and theoretical basis for the development of a new generation of environment-friendly protective materials.

Description

Technical Field

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

[0002] In marine environments, wind power equipment faces various harsh biological and chemical corrosion factors, among which microbial adhesion and biofilm formation are major threats. Once microorganisms adhere to the equipment surface, they rapidly multiply and form biofilms. These biofilms not only accelerate the corrosion process but also affect the equipment's power efficiency and increase maintenance and operating costs. Therefore, developing coatings with excellent antimicrobial adhesion properties is crucial for ensuring the long-term stable operation of marine wind power equipment.

[0003] Traditional antimicrobial coatings typically rely on chemical bactericides or heavy metal ions. While these materials can prevent microbial adhesion to some extent, prolonged use can have serious negative impacts on marine ecosystems. Therefore, in recent years, some novel environmentally friendly coating technologies have been developed, such as photocatalytic coatings and zwitterionic polymer coatings. However, single-coating technologies often struggle to maintain long-term effectiveness in complex marine environments, especially under low light conditions at night, where their antimicrobial performance is significantly reduced. Therefore, it is necessary to design a composite coating with all-weather antimicrobial properties. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems existing in the prior art and to provide an antibacterial composite coating, its preparation method and application.

[0005] This invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides an antibacterial composite coating comprising a primer and a topcoat, wherein the topcoat comprises nanoparticles, a zwitterionic polymer and a binder; wherein the nanoparticles comprise barium titanate and a polypyrrole layer and a polydopamine layer sequentially coated on the surface of the barium titanate.

[0007] The antibacterial composite coating of this invention aims to achieve the dual functions of photocatalytic antibacterial properties during the day and antimicrobial adhesion at night. This antibacterial composite coating comprises a primer and a topcoat covering the primer surface. The topcoat comprises barium titanate (BaTiO3) nanoparticles encapsulated in polypyrrole (PPy)-polydopamine (PDA), a zwitterionic polymer, and a binder. The barium titanate nanoparticles possess excellent photocatalytic activity, generating reactive oxygen species (such as hydroxyl radicals and singlet oxygen) under sunlight irradiation, effectively disrupting bacterial cell membranes and nucleic acids, thus exhibiting strong antibacterial capabilities. The encapsulation with polypyrrole and polydopamine enhances the stability of the barium titanate nanoparticles and improves their dispersibility and adhesion within the coating. Furthermore, the zwitterionic polymer possesses superhydrophobicity and good antiprotein adsorption properties, effectively inhibiting the adhesion and growth of microorganisms on equipment surfaces at night or in the absence of light. In summary, the antibacterial composite coating of this invention combines photocatalytic antibacterial properties and zwitterionic antiadhesion, achieving continuous antimicrobial protection day and night through the organic combination of these structural elements. The development of this antibacterial composite coating can not only significantly improve the service life of marine wind power equipment, but also provide important technical support and theoretical basis for the development of a new generation of environmentally friendly protective materials.

[0008] Preferably, the mass ratio of barium titanate, polypyrrole, and polydopamine in the nanoparticles is (5-8):(0.5-1):(1-3).

[0009] Preferably, the thickness of the primer is 50μm-70μm, and the thickness of the topcoat is 30μm-50μm.

[0010] The nanoparticles of this invention encapsulate barium titanate with polypyrrole-polydopamine, exhibiting strong photocatalytic antibacterial capabilities. Furthermore, polypyrrole, as a conductive polymer, enhances photocatalytic efficiency, while polydopamine, as a biomimetic adhesive, improves the adhesion and stability of the particles within the coating matrix. Replacing polypyrrole or polydopamine with other polymers would degrade the material's performance.

[0011] Preferably, the zwitterionic polymer includes at least one of sulfobetaine methacrylate (PSBMA), polyethylene glycol quaternary ammonium salt, and polymethacryloyl ethyl sulfobetaine.

[0012] More preferably, the zwitterionic polymer is sulfobetaine methacrylate.

[0013] PSBMA possesses excellent resistance to protein adsorption and superhydrophobic properties, enabling it to inhibit the attachment and growth of microorganisms even in the absence of light. Therefore, PSBMA plays a crucial antibacterial role at night or in dark conditions, providing the coating with continuous antimicrobial adhesion properties day and night.

[0014] Preferably, the adhesive includes at least one of polyurethane (PU), acrylate adhesive, and rubber adhesive.

[0015] More preferably, the adhesive is polyurethane.

[0016] To further enhance the mechanical properties and weather resistance of the coating, polyurethane can be introduced as a binder. Polyurethane not only has excellent mechanical strength, elastic modulus and wear resistance, but also improves the coating's chemical corrosion resistance and weather resistance, effectively enhancing the overall mechanical properties of the coating and ensuring the coating's durability and stability in marine environments.

[0017] Preferably, in the topcoat, the mass ratio of the nanoparticles, the zwitterionic polymer and the binder is (1-2):1:(1-1.5).

[0018] This invention effectively improves the antifouling effect of the coating by adding polyurethane and zwitterionic polymer. If zwitterionic polymer or polyurethane is missing, the antifouling performance of the coating will decrease.

[0019] Preferably, the primer comprises an epoxy resin; the epoxy resin comprises a bisphenol A type epoxy resin.

[0020] The primer is made of epoxy resin with excellent corrosion resistance, providing good adhesion to the substrate and mechanical stability. As the first layer of the coating, the primer bonds tightly to the substrate, providing basic protection and a solid foundation for subsequent functional topcoats.

[0021] Secondly, the present invention provides a method for preparing the aforementioned antibacterial composite coating, comprising the following steps:

[0022] (1) Apply the primer solution to the substrate surface to obtain the primer;

[0023] (2) Disperse barium titanate particles in a solvent, add pyrrole, initiate pyrrole polymerization under the action of an oxidant, add dopamine, heat and polymerize to obtain nanoparticles, mix the obtained nanoparticles, zwitterionic polymer and binder evenly to obtain a topcoat solution, coat the obtained topcoat solution on the surface of the primer obtained in step (1) to obtain the antibacterial composite coating.

[0024] The preparation method of the antibacterial composite coating of the present invention is simple and suitable for large-scale industrial production.

[0025] In one specific embodiment of the present invention, step (1) is: mixing epoxy resin, curing agent and solvent evenly to obtain a primer solution, coating the obtained primer solution on the substrate surface, and curing to obtain a primer.

[0026] Preferably, the curing agent comprises an aliphatic amine curing agent, and the solvent comprises anhydrous ethanol.

[0027] Preferably, the weight ratio of the epoxy resin to the curing agent is (3-5):1.

[0028] Preferably, in step (2), the mass ratio of barium titanate particles, pyrrole, and dopamine is (5-8):(0.5-1):(1-3).

[0029] Preferably, in step (2), the oxidant includes a ferric oxide solution with a concentration of 0.1 mol / L to 0.2 mol / L.

[0030] Preferably, in step (2), the temperature of the pyrrole polymerization does not exceed 5°C and the time is not less than 3 hours; further, the temperature of the pyrrole polymerization is 0°C-5°C and the time is 3 hours-4 hours.

[0031] Preferably, in step (2), the heating polymerization temperature is 18℃-37℃ and the time is 12h-24h.

[0032] Preferably, in step (2), the heating polymerization is carried out in a triethanolamine buffer solution with a pH of 8.5-9.5.

[0033] Preferably, the coating method includes at least one of spraying, brushing, and rolling. The coating process must ensure uniformity and smoothness.

[0034] Thirdly, the present invention provides the application of the antibacterial composite coating in marine wind power equipment.

[0035] The antibacterial composite coating of the present invention provides all-weather protection against microbial adhesion for marine wind power equipment through a dual antibacterial mechanism that operates day and night.

[0036] The present invention offers the following advantages: The composite coating provided by this invention, through rational material selection and coating structure design, achieves dual functions of daytime photocatalytic antibacterial properties and nighttime antimicrobial adhesion, exhibiting significant antifouling effects. This coating can effectively extend the service life of marine wind power equipment, reduce maintenance costs, and has broad application prospects. The preparation method of the antibacterial composite coating of this invention is simple, suitable for large-scale industrial production, and meets environmental protection requirements, providing a new solution for the protection of marine wind power equipment. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the antibacterial composite coating in Example 1;

[0038] Figure 2 The image shows a scanning electron microscope image of the nanoparticles in Example 1.

[0039] Figure 3 This is a scanning electron microscope image of the antibacterial composite coating of Example 1;

[0040] Figure 4 The images show the photocatalytic antibacterial results of the antibacterial composite coating and the blank polyurethane coating in Example 1.

[0041] Figure 5 This is a schematic diagram showing the anti-adhesion results of the antibacterial composite coating and the blank polyurethane coating in Example 1. Detailed Implementation

[0042] To better illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described below with reference to specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0043] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0044] Example 1

[0045] A method for preparing the antibacterial composite coating includes the following steps:

[0046] (1) Mix bisphenol A type epoxy resin (E-44) and aliphatic amine curing agent at a weight ratio of 4:1, add an appropriate amount of anhydrous ethanol to dilute, stir evenly and let stand to degas, and obtain a primer solution. Apply the obtained primer solution evenly to the substrate surface by spraying. After coating, cure naturally overnight at room temperature to obtain a primer with a thickness of 55μm.

[0047] (2) Disperse 6g of barium titanate (BaTiO3) nanoparticles in 100ml of deionized water and ultrasonically disperse them to make the particles evenly distributed. Add 0.7g of pyrrole monomer to the dispersion and slowly add ferric oxide solution (concentration of 0.15mol / L) while stirring continuously. Control the reaction temperature at 4℃ and continue the reaction for 4h to obtain barium titanate particles with a layer of polypyrrole on the surface.

[0048] The above-mentioned polypyrrole-coated barium titanate nanoparticles were dispersed in a triethanolamine buffer solution with a pH of 9, and 2g of dopamine monomer was added. The mixture was stirred and reacted overnight at 20°C to form a polydopamine layer on the surface. After the reaction was completed, the nanoparticles (PPy / PDA@BaTiO4) were obtained by repeatedly washing with deionized water and centrifuging to precipitate the precipitate. The nanoparticles were then dried to obtain nanoparticles. The mass ratio of barium titanate, polypyrrole and polydopamine in the obtained nanoparticles was 6:0.7:2.

[0049] Take 1.5g of the prepared nanoparticles and add them to 50mL of PSBMA aqueous solution (concentration of 2% w / v, g / mL). Stir with a high-speed stirrer to ensure that the nanoparticles are uniformly dispersed. Slowly add 10mL of polyurethane prepolymer solution (concentration of 13% w / v, g / mL) to the mixed solution and continue stirring to obtain the topcoat solution.

[0050] The topcoat solution was applied to the surface of the primer obtained in step (1) by spraying. After the topcoat was applied, it was left at room temperature for a certain period of time to cure naturally, thus obtaining the antibacterial composite coating. The thickness of the topcoat layer was 40 μm.

[0051] Example 2

[0052] A method for preparing the antibacterial composite coating includes the following steps:

[0053] (1) Mix bisphenol A type epoxy resin (E-44) and aliphatic amine curing agent at a weight ratio of 4:1, add an appropriate amount of anhydrous ethanol to dilute, stir evenly and let stand to degas, and obtain a primer solution. Apply the obtained primer solution evenly to the substrate surface by spraying. After coating, cure naturally overnight at room temperature to obtain a primer with a thickness of 50μm.

[0054] (2) Disperse 8g of barium titanate (BaTiO3) nanoparticles in 100ml of deionized water and ultrasonically disperse them to make the particles evenly distributed. Add 0.5g of pyrrole monomer to the dispersion and slowly add 0.1mol / L of ferric oxide solution as an oxidant while stirring continuously. Control the reaction temperature at 5℃ and continue the reaction for 4h to obtain barium titanate particles with a polypyrrole coating on the surface.

[0055] The above-mentioned polypyrrole-coated barium titanate nanoparticles were dispersed in a triethanolamine buffer solution with a pH of 8.5, and 3g of dopamine monomer was added. The mixture was stirred and reacted overnight at 20°C to form a polydopamine layer on the surface. After the reaction was completed, the nanoparticles were repeatedly washed with deionized water and precipitated by centrifugation and dried to obtain nanoparticles. The mass ratio of barium titanate, polypyrrole and polydopamine in the obtained nanoparticles was 8:0.5:3.

[0056] Take 1g of the prepared nanoparticles and add them to 50mL of PSBMA aqueous solution (concentration of 2% w / v, g / mL). Stir with a high-speed stirrer to ensure that the nanoparticles are uniformly dispersed. Slowly add 10mL of polyurethane prepolymer solution (concentration of 10% w / v, g / mL) to the mixed solution and continue stirring to obtain the topcoat solution.

[0057] The topcoat solution was applied to the surface of the primer obtained in step (1) by spraying. After the topcoat was applied, it was left at room temperature for a certain period of time to cure naturally, thus obtaining the antibacterial composite coating. The thickness of the topcoat layer was 30 μm.

[0058] Example 3

[0059] A method for preparing the antibacterial composite coating includes the following steps:

[0060] (1) Mix bisphenol A type epoxy resin (E-44) and aliphatic amine curing agent at a weight ratio of 4:1, add an appropriate amount of anhydrous ethanol to dilute, stir evenly and let stand to degas, and obtain a primer solution. Apply the obtained primer solution evenly to the substrate surface by spraying. After coating, cure naturally overnight at room temperature to obtain a primer with a thickness of 55μm.

[0061] (2) Disperse 5g of barium titanate (BaTiO3) nanoparticles in 100ml of deionized water and ultrasonically disperse them to make the particles evenly distributed. Add 1g of pyrrole monomer to the dispersion and slowly add 0.2mol / L of ferric oxide solution as an oxidant while stirring continuously. Control the reaction temperature at 4℃ and continue the reaction for 3h to obtain barium titanate particles with a polypyrrole coating on the surface.

[0062] The above-mentioned polypyrrole-coated barium titanate nanoparticles were dispersed in a triethanolamine buffer solution with a pH of 8.5, and 1g of dopamine monomer was added. The mixture was stirred and reacted overnight at 20°C to form a polydopamine layer on the surface. After the reaction was completed, the nanoparticles were repeatedly washed with deionized water and precipitated by centrifugation and dried to obtain nanoparticles. The mass ratio of barium titanate, polypyrrole and polydopamine in the obtained nanoparticles was 5:1:1.

[0063] Take 2g of the prepared nanoparticles and add them to 50mL of PSBMA aqueous solution (concentration of 2% w / v, g / mL). Stir with a high-speed stirrer to ensure that the nanoparticles are uniformly dispersed. Slowly add 10mL of polyurethane prepolymer solution (concentration of 15% w / v, g / mL) to the mixed solution and continue stirring to obtain the topcoat solution.

[0064] The topcoat solution was applied to the surface of the primer obtained in step (1) by spraying. After the topcoat was applied, it was left at room temperature for a certain period of time to cure naturally, thus obtaining the antibacterial composite coating. The thickness of the topcoat layer was 50 μm.

[0065] Comparative Example 1

[0066] The difference between the preparation method of the antibacterial coating in this comparative example and that in Example 1 lies only in the preparation method of the nanoparticles. The preparation method of the nanoparticles in this comparative example is as follows: 6g of barium titanate is dispersed in a triethanolamine buffer solution with a pH of 9, 2g of dopamine monomer is added, and the mixture is stirred and reacted overnight at 20°C to form a polydopamine layer on its surface. After the reaction is complete, the nanoparticles are obtained by repeated washing with deionized water, centrifugation, and drying. All other steps are the same as in Example 1. In other words, the difference between this comparative example and Example 1 is only that the barium titanate is coated with polydopamine in the nanoparticles.

[0067] A schematic diagram of the antibacterial composite coating in Example 1 is shown below. Figure 1 As shown; the nanoparticles and antibacterial composite coating of Example 1 were characterized by scanning electron microscopy, and the results are as follows. Figure 2 and Figure 3 .

[0068] Figure 2 The image shows a scanning electron microscope image of the nanoparticles in Example 1. As can be seen from the image, the nanoparticles are approximately 120 nm in size and have a regular particle shape. Figure 3 The image shows a scanning electron microscope image of the antibacterial composite coating in Example 1, where the nanoparticles are uniformly dispersed in the zwitterionic polymer and binder.

[0069] The photoresponsive antibacterial properties of the antibacterial composite coating in Example 1 were evaluated using a Gram-positive Staphylococcus aureus strain. The specific procedures are as follows:

[0070] (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.

[0071] (2) In vitro antibacterial efficiency test:

[0072] The bacterial stock solution was serially diluted with shaking, and 500 μL of each solution was added to the sample wells of a 48-well plate. The absorbance value at a wavelength of 600 nm was detected using a multi-mode microplate reader. The bacterial concentration was tested by photoelectric turbidimetry. The solution was diluted to a fixed factor, and an appropriate amount of bacterial solution was added to the sample wells.

[0073] Samples were divided into a dark group and a light group, with a polyurethane coating used as a blank control. Both groups were co-cultured in a 37℃ biochemical incubator for 3 hours. The light group was then treated with a simulated sunlight xenon lamp for 1 hour. Afterward, the bacterial 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 plates were then incubated at 37℃ for an appropriate time, and the colony count (N) on the solid agar plates was photographed and recorded. Four replicates were prepared for each sample group. The antibacterial efficiency was calculated using the following formula:

[0074] Test results are as follows Figure 4 As shown.

[0075] from Figure 4 As can be seen, almost all Staphylococcus aureus adhering to the coating surface died under sunlight irradiation. Test results show that under simulated sunlight xenon lamp irradiation, the antibacterial rate of the coating can reach 99.92%. Therefore, the antibacterial composite coating of this invention exhibits excellent photocatalytic antibacterial properties and is very suitable for application on the surface of marine wind power equipment.

[0076] The antimicrobial adhesion properties of the antibacterial composite coating in Example 1 were tested using the following method:

[0077] The bacterial stock solution was serially diluted with shaking, and 500 μL of each solution was added to the sample wells of a 48-well plate. The absorbance value at a wavelength of 600 nm was detected using a multi-mode microplate reader. The bacterial concentration was tested by photoelectric turbidimetry. The solution was diluted to a fixed factor, and an appropriate amount of bacterial solution was added to the sample wells.

[0078] The experiment was conducted in darkness to simulate the anti-adhesion effect of the coating at night, with a polyurethane coating used as a blank control. Both groups of samples were co-incubated at 37°C for 3 hours. The bacterial suspension was then 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. Subsequently, the plates were incubated at 37°C for an appropriate time, and the colony count (N) on the solid agar plates was photographed and recorded. Four replicates were prepared for each group of samples.

[0079] Test results are as follows Figure 5 As shown.

[0080] from Figure 5 As can be seen, most of the Staphylococcus aureus adhering to the coating surface are dead, exhibiting a high anti-adhesion rate. Therefore, the coating can play an important anti-adhesion role at night or in dark conditions, giving it continuous antimicrobial adhesion performance day and night.

[0081] The antibacterial and antimicrobial adhesion tests were also performed on the coating of Comparative Example 1. The test results showed that the antibacterial and antimicrobial adhesion effects of the coating of Comparative Example 1 were lower than those of Example 1. This indicates that the antibacterial composite coating of the present invention has excellent antibacterial and antifouling effects.

[0082] 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. An antibacterial composite coating, characterized in that, The coating comprises a primer and a topcoat. The topcoat comprises nanoparticles, a zwitterionic polymer, and a binder. The nanoparticles comprise barium titanate and a polypyrrole layer and a polydopamine layer sequentially coated on the surface of the barium titanate. The zwitterionic polymer is sulfobetaine methacrylate, and the binder is polyurethane. In the topcoat, the mass ratio of the nanoparticles, the zwitterionic polymer, and the binder is (1-2):1:(1-1.5). The preparation method of the nanoparticles is as follows: barium titanate particles are dispersed in a solvent, pyrrole is added, pyrrole polymerization is initiated under the action of an oxidant, dopamine is added, and polymerization is carried out by heating to obtain nanoparticles; the mass ratio of barium titanate particles, pyrrole and dopamine is (5-8):(0.5-1):(1-3).

2. The antibacterial composite coating according to claim 1, characterized in that, The thickness of the primer is 50μm-70μm, and the thickness of the topcoat is 30μm-50μm.

3. The antibacterial composite coating according to claim 1, characterized in that, The oxidant includes a solution of iron(III) oxide.

4. The antibacterial composite coating according to claim 1, characterized in that, The pyrrole polymerization temperature does not exceed 5°C and the time is not less than 3 hours.

5. The antibacterial composite coating according to claim 1, characterized in that, The heating polymerization temperature is 18℃-37℃, and the time is 12h-24h.

6. The antibacterial composite coating according to claim 1, characterized in that, The primer includes epoxy resin.

7. A method for preparing an antibacterial composite coating according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Apply the primer solution to the substrate surface to obtain the primer; (2) Mix the nanoparticles, zwitterionic polymer and binder evenly to obtain a topcoat solution. Apply the obtained topcoat solution to the surface of the primer obtained in step (1) to obtain the antibacterial composite coating.

8. The application of the antibacterial composite coating according to any one of claims 1-6 in marine wind power equipment.

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