Antibacterial and hydrophobic synchronous self-repairing nano-particles, preparation method thereof and antibacterial and hydrophobic synchronous self-repairing coating

Abstract

The invention discloses antibacterial and hydrophobic synchronous self-repairing nanoparticles, a preparation method thereof and an antibacterial and hydrophobic synchronous self-repairing coating, and belongs to the technical field of antibacterial coatings. The preparation method comprises the following steps: preparing SiO2, long-chain fatty amine and nano Ag particles with a core-shell structure by taking the long-chain fatty amine and nano Ag particles as templates, coating the surface of SiO2 with polydopamine to generate nano silver particles in situ, and carrying out double hydrophobic modification on the polydopamine by using stearic acid and octadecylamine, so that the nano silver particles are obtained. The nano-particles obtained by the method have higher antibacterial, hydrophobic and wear-resisting properties, and can synchronously and quickly realize the repair of the hydrophobic and antibacterial properties when the nano-particles are subjected to serious mechanical damage.

Description

Technical Field

[0001] This invention belongs to the field of antibacterial coating technology, specifically relating to an antibacterial, hydrophobic, and self-healing nanoparticle and its preparation method, as well as an antibacterial, hydrophobic, and self-healing coating. Background Technology

[0002] Microorganisms permeate all aspects of life, and the continuous accumulation of pathogenic microorganisms on everyday items, hygiene products, and medical supplies that humans frequently come into contact with poses a significant threat to health. Therefore, the development of antibacterial coating materials has received widespread attention. Currently used antibacterial coatings typically possess hydrophobic properties, which can reduce the adsorption and proliferation of microorganisms, further enhancing their antibacterial performance. However, most coatings have a short lifespan, limiting their use in media requiring long-term application. Therefore, to extend the lifespan of coatings, it is necessary to develop coating materials with self-healing capabilities, enabling them to self-repair under repeated wear and prolonged use.

[0003] Existing research mainly focuses on self-healing properties with a single function, or has significant shortcomings in achieving multiple functions simultaneously. For example, Chinese patent CN115746661A discloses a method for preparing a self-healing hydrophobic antibacterial and anti-corrosion coating. This method achieves the bactericidal effect after capsule breakage by encapsulating an antibacterial agent in the outer core material of a double-core, double-arm microcapsule. However, the bactericides used are metronidazole, tetracycline, and triclosan, which are prone to drug resistance during use, have poor antibacterial performance, and have a long self-healing time. Chinese patent CN118834556A discloses a near-infrared photothermal self-healing superhydrophobic material. It effectively improves the hydrophobicity of the coating by coating SiO2@PDA particles with a layer of ODA. However, it can only achieve the repair of a single hydrophobic function, and the overall wear resistance of the material is poor; after 20 rubs, its hydrophobic angle has significantly decreased.

[0004] In summary, existing self-healing coatings still have significant shortcomings in terms of simultaneous multi-functional repair, long-term wear resistance, and the selection of antibacterial agents. Therefore, there is an urgent need to develop a new material system that can simultaneously restore hydrophobic and antibacterial properties in a single repair process, possess strong mechanical durability, and employ safe and efficient antibacterial components to meet the dual requirements of performance and lifespan in practical applications. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the first objective of this invention is to provide a nanoparticle that is simultaneously antibacterial, hydrophobic, and self-healing. This nanoparticle, through the synergistic effect of a multi-layered core-shell structure, double hydrophobic modification of the outer layer, and simultaneous encapsulation of long-chain fatty acids and nano-Ag particles in the core, enables the material to possess high antibacterial, hydrophobic, and wear-resistant properties. Furthermore, it can simultaneously and rapidly repair its hydrophobic and antibacterial properties when subjected to severe mechanical damage.

[0006] The second objective of this invention is to provide a method for preparing antibacterial, hydrophobic, and self-healing nanoparticles. This method is simple in process, uses readily available materials, and has the potential for industrial production.

[0007] The third objective of this invention is to provide an antibacterial, hydrophobic, and self-healing coating that utilizes antibacterial, hydrophobic, and self-healing nanoparticles combined with a photoinitiator to achieve rapid curing under ultraviolet light. This coating exhibits excellent simultaneous self-healing hydrophobic properties and antibacterial properties, significantly extending the service life of the coating material.

[0008] To achieve the above technical objectives, this invention provides a method for preparing antibacterial, hydrophobic, and simultaneously self-healing nanoparticles, comprising the following steps:

[0009] S1 uses a complexation-reduction reaction between silver nitrate and long-chain fatty amines to obtain long-chain fatty amine@Ag nanoparticles;

[0010] S2 uses long-chain fatty amine@nano Ag particles as templates and silicate compounds to obtain SiO2@long-chain fatty amine@nano Ag particles via sol-gel method;

[0011] S3 dispersed SiO2@long-chain fatty amine@nano Ag particles in a dopamine solution for self-assembly to obtain PDA@SiO2@long-chain fatty amine@nano Ag particles;

[0012] S4 adds PDA@SiO2@long-chain fatty amine@nano Ag particles to silver nitrate aqueous solution to undergo a reduction reaction, and obtains PDA@SiO2@long-chain fatty amine@nano Ag particles with nano Ag particles loaded on the surface.

[0013] S5 is obtained by hydrophobically modifying PDA@SiO2@long-chain fatty amine@nano-Ag particles loaded with nano-Ag particles on the surface using octadecylamine and stearic acid as hydrophobic modifiers.

[0014] This invention utilizes long-chain fatty amines to reduce silver nitrate, forming long-chain fatty amine@Ag nanoparticles. These nanoparticles are then used as templates to prepare core-shell structured SiO2@long-chain fatty amine@Ag nanoparticles via a sol-gel method. Polydopamine is coated onto a silica shell. The catechol structure of polydopamine reduces silver ions to Ag and is itself oxidized to benzoquinone. Benzoquinone reacts with octadecylamine to form a Schiff base, and the amino group of polydopamine undergoes an amidation reaction with stearic acid. The use of stearic acid and octadecylamine for dual hydrophobic modification of polydopamine reduces the risk of exposure of the hydrophilic polydopamine layer due to alkyl chain loss, thereby improving the self-healing rate.

[0015] The key to the technical solution of this invention lies in the selection of each layer component in the core-shell structure of the nanoparticles, the sequential connection between layers, and the dual hydrophobic modification of the outermost layer. Specifically, firstly, the inner long-chain aliphatic amine@nano-Ag particles not only serve as a silver source to provide continuous antibacterial ability, but the outer long-chain alkyl groups also initially endow the particles with certain hydrophobic properties and provide a template basis for subsequent silicon shell coating. The SiO2 intermediate layer not only stabilizes the core structure and controls the release of silver ions, but also provides reaction sites for the self-assembly of the PDA layer due to its high specific surface area and surface hydroxyl groups, thus enhancing the interlayer bonding force. When the polydopamine (PDA) layer is introduced in situ, the PDA not only serves as a reaction platform for silver ion reduction, enabling secondary loading of high-density nano-silver particles on the particle surface and significantly improving antibacterial efficiency; its abundant catechol / quinone groups and amino groups also provide excellent interfacial chemical activity. In step S4, while reducing silver ions to silver nanoparticles, the PDA itself is oxidized to a quinone structure. This quinone group can undergo a Schiff base reaction with the amino groups of the outer long-chain aliphatic amines, forming a dynamically reversible covalent bond, achieving chemical immobilization of the hydrophobic chains and autonomous repair after damage. Simultaneously, the outermost double hydrophobic modification further constructs a robust superhydrophobic barrier through the synergistic effect of octadecylamine and stearic acid. Octadecylamine reacts with the benzoquinone formed after the reduction of silver ions in the PDA layer to generate a Schiff base, aligning the alkyl chains outwards to form a low surface energy layer. Meanwhile, stearic acid fills the gaps between octadecylamine molecules through the amidation reaction of its carboxyl groups with the residual amino groups in the PDA, forming a denser and more stable hydrophobic film. This structure not only significantly improves the static hydrophobic properties of the material but also, during physical wear, enables automatic migration and surface reconstruction of the hydrophobic chains through the reversible breaking and recombination of Schiff base bonds, allowing for rapid recovery of hydrophobic properties.

[0016] Furthermore, the antibacterial and hydrophobic self-healing process of the nanoparticles formed in this invention can be divided into three stages according to different degrees of mechanical damage: In the initial use, the dense hydrophobic layer on the outer layer of the nanoparticles and the loaded silver nanoparticles can provide high antibacterial and hydrophobic properties. When minor daily wear occurs, under light irradiation (especially near-infrared light), the excellent photothermal effect of PDA can stimulate the migration of undamaged long-chain alkyl groups in the lower layer to the surface, quickly repairing the hydrophobic properties. When deeper scratches occur, the Schiff base formed by the quinone group of the PDA layer and the amino group of the octadecylamine in the upper layer can be dynamically and reversibly broken and recombined to repair macroscopic physical damage. At the same time, when severe mechanical damage occurs and the middle silica coating layer is damaged, the long-chain fatty amine@Ag nanoparticles wrapped inside are released simultaneously, which not only repairs the hydrophobic function but also repairs and enhances the antibacterial function, ensuring the reliability and durability of the material under extreme conditions.

[0017] Furthermore, experiments revealed that the order of the process steps in this invention is also crucial. If S2 and S3 are interchanged, and SiO2 is coated on the outside, the contact between the internal PDA and the silver nitrate, octadecylamine, stearic acid, etc., outside the SiO2 will be significantly reduced, greatly affecting the reaction rate and effect. Consequently, the coating will not possess its initial excellent hydrophobic and antibacterial properties. However, if S4 and S5 are interchanged, octadecylamine and stearic acid react with polydopamine first, occupying reaction sites and weakening its reducing ability for silver nitrate. This drastically reduces the number of silver nanoparticles in the outer layer, thus significantly decreasing the antibacterial effect of the coating.

[0018] As a preferred embodiment, the long-chain aliphatic amine is a C10-C18 aliphatic amine. The long-chain aliphatic amine selected in this invention also possesses a relatively long alkyl chain to improve the hydrophobic properties of the nanoparticles, while the amine group can bond with the reduced silver ions to form a stable structure. Octadecylamine (ODA) is further preferred.

[0019] As a preferred embodiment, in S1, the concentration ratio of silver nitrate to long-chain fatty amine is 1:(1~10); the volume ratio of silver nitrate to long-chain fatty amine is (1~10):1; the particle size of the long-chain fatty amine@Ag nanoparticles is 10~50 nm; and the conditions for the complexation-reduction reaction are: temperature 70~90℃, time 3~6 h. It has been found that the particle size of silver nanoparticles prepared using a lower concentration of long-chain fatty amine solution is larger than that prepared using a higher concentration of long-chain fatty amine solution, and the smaller the particle size of the silver nanoparticles, the stronger the bactericidal performance. Therefore, to ensure the antibacterial and self-healing properties of the material, the concentration of long-chain fatty amine in this invention must be significantly greater than the concentration of silver nitrate.

[0020] As a preferred embodiment, in S2, the sol-gel method uses alcohol-based reagents as solvents and mixes at room temperature under alkaline conditions; the mass ratio of the long-chain fatty amine@nano-Ag particles to silicate compounds is 1:(10~30). By controlling the mass ratio of the long-chain fatty amine@nano-Ag particles to silicate compounds, the thickness of the coated silica layer can be controlled. If the amount of silicate compounds is too small, the silica layer will be too thin, reducing the wear resistance of the nanoparticles; conversely, if the amount of silicate compounds is too large, the silica layer will be too thick, which, on the one hand, hinders the release of internal silver ions, resulting in a slow antibacterial repair speed, and on the other hand, reduces the light transmittance of the nanoparticles. Further, ammonia is added to adjust the pH of the system to 9~11.

[0021] Furthermore, the thickness of the silica layer coating in the nanoparticles is 5~30nm.

[0022] As a preferred embodiment, the silicate compound includes tetraethyl orthosilicate.

[0023] As a preferred embodiment, in S3, the self-assembly conditions are: pH 8.5~10, time 4~10h; the mass ratio of SiO2@long-chain fatty amine@nano Ag particles to dopamine is 1:(2~6). An alkaline environment promotes rapid self-polymerization of dopamine, forming polydopamine which coats the outer layer of the SiO2@long-chain fatty amine@nano Ag particles.

[0024] As a preferred embodiment, in step S4, the reduction reaction conditions are: temperature 70-80℃, time 2-4h, and the molar ratio of silver nitrate to PDA@SiO2@long-chain fatty amine@nano Ag particles in the silver nitrate aqueous solution is (10-30):1. The catechol structure of polydopamine can be used to reduce silver nitrate to nano-silver, which is then loaded onto the surface of PDA@SiO2@long-chain fatty amine@nano Ag particles, achieving highly efficient antibacterial properties on the outer layer.

[0025] As a preferred embodiment, in step S5, the molar ratio of the hydrophobic modifier to the PDA@SiO2@long-chain fatty amine@nano-Ag particles with surface-loaded nano-Ag particles is (20~60):1; the hydrophobic modification conditions are 25~70℃ and 12~24h. A low molar ratio of the hydrophobic modifier will reduce the hydrophobic effect, while a high molar ratio will cause excessive agglomeration of the hydrophobic modifier in the solution. Within the molar ratio range of this invention, it helps to uniformly graft and modify the particle surface, forming stable composite particles and reducing the agglomeration of the hydrophobic modifier.

[0026] As a preferred embodiment, the hydrophobic modification can be performed by first adding stearic acid for modification, and then adding octadecylamine for modification; or by first adding octadecylamine for modification, and then adding stearic acid for modification.

[0027] Furthermore, octadecylamine is first used for modification, followed by stearic acid modification. Octadecylamine and PDA are bonded by covalent bonds, which have a stronger binding force than the ionic / hydrogen bonds between stearic acid and PDA, resulting in better stability and greater resistance to mechanical friction.

[0028] The present invention also provides antibacterial, hydrophobic, and self-healing nanoparticles, which are obtained by the above preparation method and have a spherical morphology with a core-shell structure.

[0029] Finally, this invention also provides an antibacterial, hydrophobic, and self-healing coating, comprising the antibacterial, hydrophobic, and self-healing nanoparticles as described in claim 8, an adhesive, and a solvent. This coating utilizes the antibacterial, hydrophobic, and self-healing nanoparticles combined with the adhesive, achieving rapid curing through heating. It exhibits high antibacterial, hydrophobic, and wear-resistant properties, and when subjected to severe mechanical damage, it can simultaneously and rapidly repair its hydrophobic and antibacterial properties through photoactivation.

[0030] As a preferred embodiment, the antibacterial, hydrophobic, and self-healing coating comprises the following components by weight: 1-5 parts of the antibacterial, hydrophobic, and self-healing nanoparticles as described in claim 8, 1-3 parts of the adhesive, and 200-500 parts of the solvent.

[0031] As a preferred embodiment, the adhesive comprises at least one of natural rubber, acrylic resin, tackifying resin, polyurethane, and polyolefin adhesive; the solvent comprises at least one of ethanol, acetone, butanone, ethyl acetate, butyl acetate, toluene, ethylene glycol monomethyl ether acetate, dimethyl carbonate, and diethyl carbonate.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The antibacterial, hydrophobic and self-healing nanoparticles provided by the present invention achieve high-density, multi-layered silver nanoparticle distribution through the synergistic effect of core long-chain fatty amine@nanoAg particles and outer polydopamine (PDA) secondary loaded silver nanoparticles, which significantly improves the antibacterial efficiency of the material; at the same time, the double hydrophobic modification forms a dense and stable superhydrophobic barrier, which effectively blocks the adhesion of water and microorganisms.

[0034] (2) The antibacterial and hydrophobic self-healing nanoparticles of the present invention have a step-by-step self-healing process for different degrees of mechanical damage: when there is slight wear, the photothermal effect of PDA is used to promote the migration of the lower alkyl chain to repair hydrophobicity; when there is deeper scratch, physical macroscopic structural repair is achieved through the reversible recombination of dynamic Schiff base bonds; when there is severe damage, the core long-chain fatty amine@nanoAg particles are released to simultaneously repair hydrophobic and antibacterial functions, ensuring the reliability and durability of the coating material under extreme conditions.

[0035] (3) The present invention can balance the self-healing speed, the wear resistance and light transmittance of the material by controlling the thickness of the silica layer coated in the nanoparticles.

[0036] (4) The preparation method of the present invention is simple and the materials are readily available, and it has the potential for industrial production.

[0037] (5) The antibacterial and hydrophobic synchronous self-healing coating provided by the present invention can achieve rapid repair under a shorter period of light exposure. Attached Figure Description

[0038] Figure 1 (a) and Figure 1 In the image (b), scanning electron microscope (SEM) image (a) and transmission electron microscope (TEM) image (b) are respectively of the antibacterial, hydrophobic and self-healing nanoparticles prepared in Example 1.

[0039] Figure 2 The antibacterial, hydrophobic, and simultaneously self-healing nanoparticles prepared in Example 1 1H NMR spectrum. Detailed Implementation

[0040] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0041] Unless otherwise specified, all materials and reagents used in the embodiments of this application are commercially available.

[0042] The room temperature of this invention is 25°C.

[0043] Example 1

[0044] A method for preparing antibacterial, hydrophobic, and simultaneously self-healing nanoparticles comprises the following steps:

[0045] S1 mixed 20 mL of 0.001 M silver nitrate aqueous solution and 10 mL of octadecylamine ethanol solution of the same concentration at 70 °C, and stirred for 3 h to carry out complexation-reduction reaction. After centrifugation, washing with ethanol and water, and drying, ODA@Ag nanoparticles (average particle size of 30 nm) were obtained.

[0046] S2 At room temperature, 0.1g of ODA@nanoAg particles were ultrasonically dispersed in 50mL of ethanol, 3mL of 25wt% ammonia was added, and after stirring evenly, 2g of TEOS was slowly added and stirring was continued for 12h. After centrifugation, the particles were washed with ethanol and dried to obtain SiO2@ODA@nanoAg particles (the thickness of the SiO2 coating layer was 5~10nm).

[0047] S3 dispersed 0.5g SiO2@ODA@Ag nanoparticles in 50mL Tris-HCl buffer solution with pH 8.5, added 3g dopamine, and stirred for 5h for self-assembly. The solution color changed from milky white to dark brown. After centrifugation, washing, and drying, PDA@SiO2@ODA@Ag nanoparticles were obtained.

[0048] S4 added 1g of PDA@SiO2@ODA@nanoAg particles to 400mL of 0.001M silver nitrate aqueous solution, and stirred at 70℃ for 2h to carry out a reduction reaction, thus obtaining PDA@SiO2@ODA@nanoAg particles with nanoAg particles loaded on the surface.

[0049] S5. Add 1g of PDA@SiO2@ODA@nanoAg particles with surface-loaded nano-Ag particles to 400mL of 0.001M stearic acid ethanol solution, stir at 70℃ for 1h, let stand for 10h, centrifuge and wash with ethanol, then add to 400mL of 0.001M octadecylamine ethanol solution, stir at room temperature for 8h, centrifuge again, wash with ethanol, and dry in a 60℃ oven to obtain the final product.

[0050] Example 2

[0051] A method for preparing antibacterial, hydrophobic, and simultaneously self-healing nanoparticles comprises the following steps:

[0052] S1 mixed 20 mL of 0.001 M silver nitrate aqueous solution and 10 mL of 0.005 M octadecylamine ethanol solution at 70 °C and stirred for 3 h to carry out a complexation-reduction reaction. After centrifugation, washing with ethanol and water, and drying, ODA@Ag nanoparticles (average particle size of 26 nm) were obtained.

[0053] S2 At room temperature, 0.1g of ODA@nanoAg particles were ultrasonically dispersed in 50mL of ethanol, 3mL of 25wt% ammonia was added, and after stirring evenly, 2g of TEOS was slowly added and stirring was continued for 12h. After centrifugation, the particles were washed with ethanol and dried to obtain SiO2@ODA@nanoAg particles (the thickness of the SiO2 coating layer was 7~11nm).

[0054] S3 dispersed 0.5g SiO2@ODA@Ag nanoparticles in 50mL Tris-HCl buffer solution with pH 8.5, added 3g dopamine, and stirred for 5h for self-assembly. The solution color changed from milky white to dark brown. After centrifugation, washing, and drying, PDA@SiO2@ODA@Ag nanoparticles were obtained.

[0055] S4 added 1g of PDA@SiO2@ODA@nanoAg particles to 400mL of 0.001M silver nitrate aqueous solution, and stirred at 70℃ for 2h to carry out a reduction reaction, thus obtaining PDA@SiO2@ODA@nanoAg particles with nanoAg particles loaded on the surface.

[0056] S5. Add 1g of PDA@SiO2@ODA@nanoAg particles with surface-loaded nano-Ag particles to 400mL of 0.001M stearic acid ethanol solution, stir at 70℃ for 1h, let stand for 10h, centrifuge and wash with ethanol, then add to 400mL of 0.001M octadecylamine ethanol solution, stir at room temperature for 8h, centrifuge again, wash with ethanol, and dry in a 60℃ oven to obtain the final product.

[0057] Example 3

[0058] A method for preparing antibacterial, hydrophobic, and simultaneously self-healing nanoparticles comprises the following steps:

[0059] S1 mixed 20 mL of 0.001 M silver nitrate aqueous solution and 10 mL of octadecylamine ethanol solution of the same concentration at 70 °C, and stirred for 3 h to carry out complexation-reduction reaction. After centrifugation, washing with ethanol and water, and drying, ODA@Ag nanoparticles (average particle size of 30 nm) were obtained.

[0060] S2 At room temperature, 0.1g of ODA@nanoAg particles were ultrasonically dispersed in 50mL of ethanol, 3mL of 25wt% ammonia was added, and after stirring evenly, 2g of TEOS was slowly added and stirring was continued for 12h. After centrifugation, the particles were washed with ethanol and dried to obtain SiO2@ODA@nanoAg particles (the thickness of the SiO2 coating layer was 5~10nm).

[0061] S3 dispersed 0.5g SiO2@ODA@Ag nanoparticles in 50mL Tris-HCl buffer solution with pH 8.5, added 3g dopamine, and stirred for 5h for self-assembly. The solution color changed from milky white to dark brown. After centrifugation, washing, and drying, PDA@SiO2@ODA@Ag nanoparticles were obtained.

[0062] S4 added 1g of PDA@SiO2@ODA@nanoAg particles to 400mL of 0.001M silver nitrate aqueous solution, and stirred at 70℃ for 2h to carry out a reduction reaction, thus obtaining PDA@SiO2@ODA@nanoAg particles with nanoAg particles loaded on the surface.

[0063] S5. Add 1g of PDA@SiO2@ODA@nanoAg particles with surface-loaded nano-Ag particles to 400mL of 0.001M octadecylamine ethanol solution, stir at room temperature for 8h, centrifuge, wash, add 400mL of 0.001M stearic acid ethanol solution, stir at 70℃ for 1h, let stand for 10h, centrifuge and wash with ethanol, and dry in a 60℃ oven to obtain the final product.

[0064] Example 4

[0065] The only difference between this embodiment and Example 1 is that the mass of dopamine in S3 is changed to 1g and the self-assembly reaction time is changed to 4h. All other steps and conditions are the same.

[0066] Example 5

[0067] The only difference between this embodiment and Example 2 is that the volume of the stearic acid ethanol solution in S5 is changed to 50 mL and the concentration is changed to 0.01 M. All other steps and conditions are the same.

[0068] Example 6

[0069] The only difference between this embodiment and Embodiment 1 is that the amount of ODA@nanoAg particles in S2 is changed to 0.08g, and the stirring time is changed to 10h.

[0070] Comparative Example 1

[0071] The difference between this comparative example and Example 1 is that S1 is not performed, and an equal amount of purchased nano-silver powder (particle size 20nm) is used instead of ODA@Ag nanoparticles as a template to prepare SiO2@Ag nanoparticles. The remaining preparation steps and conditions are the same as in Example 1.

[0072] Comparative Example 2

[0073] The difference between this comparative example and Example 1 is that stearic acid was not used for hydrophobic modification in S5, while the other preparation steps and conditions are the same as in Example 1.

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 1 is that octadecylamine was not used for hydrophobic modification in S5, while the other preparation steps and conditions were the same as in Example 1.

[0076] Comparative Example 4

[0077] The difference between this comparative example and Example 1 is that before adding TEOS in step S2, CTAB is added to ethanol and stirred to completely dissolve CTAB, and then TEOS is added dropwise to react and obtain SiO2@ODA@nano Ag particles. After obtaining SiO2@ODA@nano Ag particles, the particles are soaked in 1% hydrochloric acid ethanol solution at 80°C for 12 hours to remove CTAB and obtain mesoporous SiO2@ODA@nano Ag particles. The remaining preparation steps and conditions are the same as in Example 1.

[0078] Comparative Example 5

[0079] The difference between this comparative example and Example 1 is that after step S1, step S3 (coating the ODA@Ag nanoparticles obtained in S1 with polydopamine) is performed first, followed by step S2 (coating the PDA@ODA@Ag nanoparticles with SiO2). The remaining preparation steps and conditions are the same as in Example 1.

[0080] 1g of the antibacterial, hydrophobic, and self-healing nanoparticles prepared in the examples and comparative examples were respectively mixed with 1g of TPU (polyester polyurethane adhesive, purchased from Huafeng Group Co., Ltd., specification HS-2455YH) and 500mL of ethanol, and ultrasonicated for 4h to make the mixture uniform. The mixture was then sprayed onto a glass substrate, heated at 150℃ for 30min, and cooled to obtain an antibacterial, hydrophobic, and self-healing coating.

[0081] The initial water droplet angle, initial antibacterial rate, resistance to steel wool abrasion, and water droplet angle and antibacterial rate of the coating surface were tested. The test results are shown in Tables 1 and 2 below.

[0082] Water droplet angle test method: The static contact angle of the coating was measured using a JGW-360a contact angle meter. The test liquid volume was 2 μL, and the test environment was (24±1)℃ and (45±1)% relative humidity. The water droplet contact angle was measured at five locations, and the average value was taken.

[0083] Antibacterial rate test method: Escherichia coli was tested according to the method specified in "GB / T 21866-2008 Determination of antibacterial properties and antibacterial effect of antibacterial coatings (films)".

[0084] Steel Wool Abrasion Resistance Test Method: The steel wool abrasion resistance test is conducted using a ZJ-339-GSR abrasion resistance tester. The coated substrate is fixed on the tester, the pressure is set to 1000g, the stroke is set to 40mm, and the speed is set to 40 cycles / min. After the test, the results of the substrate water droplet angle test and antibacterial performance test are recorded.

[0085]

[0086]

[0087] As shown in Table 1, the initial water droplet angles of the coatings prepared in Examples 1-6 were all higher than 156°. After 5000 rubs, the water droplet angle remained higher than 140°. After 8000 rubs, the water droplet angle decreased to 127°, but after 1 hour of light exposure, the water droplet angle increased to over 148°, indicating that the hydrophobic properties could be quickly recovered. The initial water droplet angle of Comparative Example 1 was 158°, which decreased to 121° after 8000 rubs. After 1 hour of light exposure, it could only recover to about 132°, and the repair effect was lower than that of the Examples. The water droplet angles of Comparative Examples 2 and 3 decreased to 91° and 89° respectively after rubbing, which were much lower than those of the Examples, indicating that octadecylamine and stearic acid have a significant synergistic effect in the dual hydrophobic modification of this invention. Comparative Example 4 prepared mesoporous silica for coating. Although the water droplet angle after 3000 rubs was similar to that of the examples, the hydrophobic effect of the coating was significantly weaker under severe wear, and the hydrophobic effect was worst after light exposure. This is because hydrochloric acid ethanol solution is used to remove CTAB during the preparation of mesoporous silica. The hydrochloric acid also reacts with octadecylamine in the silica, destroying the core structure. The resulting octadecylamine hydrochloride is soluble in water, and the octadecylamine salt can enter and exit the silica shell through the mesopores, severely affecting the hydrophobic self-healing performance of the coating. The overall hydrophobic performance of the coating prepared in Comparative Example 5 is lower than that of other examples and comparative examples. This is because the SiO2 is coated on the outside, and the contact between the PDA inside and the silver nitrate, octadecylamine, stearic acid, etc. outside SiO2 is greatly reduced, which greatly affects the reaction rate and effect. This leads to a significant reduction in the content of silver nanoparticles, octadecylamine, and stearic acid bound to the nanoparticle surface, thereby reducing the hydrophobicity and antibacterial properties of the coating.

[0088] As shown in Table 2, the coatings prepared in Examples 1-6 and Comparative Examples 1-5 all had an initial antibacterial rate higher than 91%. The antibacterial rate decreased after friction, but the antibacterial effect was repaired after 1 hour of light exposure. This indicates that the use of octadecylamine-silver nanoparticles as a reserve in this invention can effectively repair the hydrophobic and antibacterial properties of the coating after damage. Furthermore, the co-modification of polydopamine with stearic acid and octadecylamine can mitigate the decrease in hydrophobicity caused by coating damage.

[0089] Figure 1 The images show scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the coating material prepared in Example 1. The spherical morphology and dense and compact structure of the present invention can be clearly seen from the images.

[0090] Figure 2 To adopt 1 The spectrum obtained by H NMR testing of the nanoparticles prepared in Example 1 shows that the peak at 0.88 ppm corresponds to the hydrogen atom of -CH3, the peak at 1.3 ppm corresponds to -CH2-, the peaks at 2.2~2.3 ppm and 3.44 ppm correspond to the hydrogen atoms of -CH2 that connect the double bond and amide bond, respectively, and the peaks at 6.35 ppm and 8.01 ppm correspond to the hydrogen atoms of -OH and -NH, respectively.

Claims

1. A method for preparing antibacterial hydrophobic synchronously self-healing nanoparticles, characterized in that: The preparation method comprises the following steps: S1: obtaining long-chain fatty amine@nano Ag particles by complexation-reduction reaction of silver nitrate and long-chain fatty amine; S2: obtaining SiO2@long-chain fatty amine@nano Ag particles by sol-gel method of long-chain fatty amine@nano Ag particles and silicate compounds as a template agent; S3: obtaining PDA@SiO2@long-chain fatty amine@nano Ag particles by self-assembly of SiO2@long-chain fatty amine@nano Ag particles dispersed into dopamine solution; S4: obtaining PDA@SiO2@long-chain fatty amine@nano Ag particles with nano Ag particles loaded on the surface by reduction reaction of PDA@SiO2@long-chain fatty amine@nano Ag particles added into silver nitrate aqueous solution; S5: obtaining the PDA@SiO2@long-chain fatty amine@nano Ag particles with nano Ag particles loaded on the surface by hydrophobic modification of the PDA@SiO2@long-chain fatty amine@nano Ag particles with octadecylamine and stearic acid as hydrophobic modifiers.

2. The method according to claim 1, wherein the method is characterized by: The long-chain fatty amine is C10-C18 fatty amine. In S1, the concentration ratio of silver nitrate and long-chain fatty amine is 1:(1-10), the volume ratio of silver nitrate and long-chain fatty amine is (1-10):1, the particle size of the long-chain fatty amine@nano Ag particles is 10-50 nm, and the complexation-reduction reaction is carried out at a temperature of 70-90 ℃ for 3-6 h.

3. The method for preparing antibacterial, hydrophobic, and simultaneously self-healing nanoparticles according to claim 2, characterized in that: In S2, the sol-gel method is carried out at room temperature in an alkaline environment with an alcohol reagent as a solvent, and the mass ratio of the long-chain fatty amine@nano Ag particles and silicate compounds is 1:(10-30).

4. The method of claim 1, wherein the method is characterized by: In S3, the self-assembly is carried out at a pH of 8.5-10 for 4-10 h, and the mass ratio of the SiO2@long-chain fatty amine@nano Ag particles and dopamine is 1:(2-6).

5. The method according to any one of claims 1 to 4, wherein the method is characterized in that: In S4, the reduction reaction is carried out at a temperature of 70-80 ℃ for 2-4 h.

6. The method of claim 5, wherein the method further comprises: In S4, the molar ratio of silver nitrate and PDA@SiO2@long-chain fatty amine@nano Ag particles in the silver nitrate aqueous solution is (10-30):

1.

7. The method according to claim 6, wherein the method is characterized by: In S5, the molar ratio of the hydrophobic modifier and the PDA@SiO2@long-chain fatty amine@nano Ag particles with nano Ag particles loaded on the surface is (20-60):1, and the hydrophobic modification is carried out at a temperature of 25-70 ℃ for 12-24 h.

8. An antibacterial hydrophobic self-healing nanoparticle, characterized in that: The preparation method is obtained by any one of claims 1-7, and the obtained product has a core-shell structure and a spherical morphology.

9. An antibacterial hydrophobic self-synchronous healing coating, characterized by: The antibacterial and hydrophobic synchronous self-repairing nanoparticles, the adhesive and the solvent are used in the antibacterial and hydrophobic synchronous self-repairing nanoparticles.

10. The antibacterial hydrophobic self-mendable coating according to claim 9, characterized in that: The antibacterial and hydrophobic synchronous self-repairing nanoparticles, the adhesive and the solvent are used in the antibacterial and hydrophobic synchronous self-repairing nanoparticles.

Images