Nano-silver-containing modified nano antibacterial coating and preparation method thereof

Abstract

The invention discloses a nano-silver-containing modified nano antibacterial coating and a preparation method thereof, and belongs to the technical field of composite high polymer materials. The method comprises the following steps: mixing silver nitrate, polyvinylpyrrolidone, p-phenylenediamine, isophthaloyl dichloride and ferric chloride hexahydrate according to a specific mass ratio in parts by weight, carrying out hydrothermal reaction and electrochemical etching, and re-dispersing in a polyethyleneimine aqueous solution; the preparation method comprises the following steps: dissolving polyacrylonitrile powder in N, N-dimethylformamide, carrying out electrostatic spinning, hot pressing and ethylenediamine dipping, and then spraying silver nanowire sol; spin-coating a lithium fluoride solution and baking; coating a hexagonal boron nitride nanosheet and polyetherimide mixed slurry, and drying; spin-coating bisphenol F epoxy resin and curing; and performing wet micro-etching on a potassium hydroxide solution, cleaning and drying. Through surface modification and three-dimensional network construction, the dispersion stability and antibacterial durability of the nano-silver are improved, the nano-silver is suitable for the surface of a touch display module, and efficient, lasting antibacterial, high-transparency and wear-resisting properties are provided.

Description

Technical Field

[0001] This invention belongs to the field of composite polymer materials technology, specifically, it relates to a modified nano-antibacterial coating containing nano-silver and its preparation method. Background Technology

[0002] With the increasing frequency of global public health emergencies and the growing awareness of health, the demand for antibacterial materials in daily life, medical applications, and electronic devices is becoming increasingly urgent. Especially on high-frequency contact surfaces such as touch display modules, medical devices, and public self-service terminals, the cross-transmission of bacteria and viruses has become a potential health hazard. Traditional surface materials often lack active antibacterial capabilities, relying solely on passive cleaning methods such as alcohol wiping or disinfectant spraying. These methods are not only cumbersome and inefficient, but may also lead to surface corrosion, functional degradation, and even secondary pollution. Therefore, developing efficient and durable antibacterial coatings has become a hot research direction in materials science. Among them, nano-silver (AgNPs or AgNWs) has attracted much attention due to its unique antibacterial properties and has been widely used in antibacterial coatings. Nano-silver releases silver ions (Ag... + It disrupts bacterial cell membranes, inhibits DNA replication and enzyme activity, achieving a broad-spectrum bactericidal effect, and exhibits highly effective inhibition against common pathogens such as Staphylococcus aureus and Escherichia coli.

[0003] Existing technologies for antibacterial nano-silver coatings mainly revolve around the preparation, dispersion, and coating construction of silver nanoparticles. In terms of preparation, hydrothermal methods and polyol methods are the mainstream approaches. For example, silver nanowires (AgNWs) with diameters of 20-50 nm and lengths of tens of micrometers can be synthesized by reacting silver nitrate with a reducing agent (such as polyvinylpyrrolidone) under high temperature and high pressure conditions. These silver nanowires possess good conductivity and antibacterial properties and are often used for antibacterial modification of transparent conductive films. Another common method is electrochemical deposition, which reduces silver ions to nanoparticles on the substrate surface to form a uniform coating. Furthermore, green synthesis methods utilize plant extracts (such as lychee peel extract) as reducing agents to synthesize silver nanoparticles, and this has been applied in antibacterial wound dressings. These methods allow for controllable silver nanoparticle sizes, typically within the 5-100 nm range, to optimize antibacterial efficacy.

[0004] In terms of coating construction, existing nano-silver antibacterial coatings mostly employ physical methods such as spraying, spin coating, or dipping to disperse nano-silver in a polymer matrix. For example, nano-silver is mixed with polyacrylonitrile or polyetherimide to form a composite coating for use on the surface of medical implants. Another strategy is plasma polymerization, which embeds nano-silver into the coating to improve stability. Furthermore, composite coatings combining other nanomaterials such as titanium dioxide or boron nitride have achieved synergistic antibacterial effects; for example, the combination of photocatalysis and silver ion release can enhance bactericidal efficiency under light irradiation. In the field of electronic devices, nano-silver coatings are commonly used in air filters or touchscreens. For example, patent CN101396627A describes a coating of nano-silver loaded on a zirconium phosphate carrier for use in air conditioning filters, achieving long-lasting antibacterial properties. Similarly, in the field of food preservation, nano-silver coatings extend shelf life by inhibiting microbial growth (e.g., patent CN102057981A).

[0005] The application of silver nanoparticle antibacterial coatings has expanded to multiple fields. In the medical field, silver nanoparticle coatings are used in implantable devices, such as urinary catheter stents or fracture fixation devices, to prevent biofilm formation and drug-resistant bacterial infections. Studies have shown that silver nanoparticles can effectively inhibit biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA), with an inhibition rate of over 99% (Reference: The antibacterial and cytotoxic effects of silver nanoparticles coated titanium implants: a narrative review, Saudi Dent J, 2024). In the consumer electronics field, silver nanoparticle coatings are applied to touchscreen surfaces, providing "touch + antibacterial" functionality and reducing the spread of bacteria on public devices (Reference: The antibacterial effects of silver, titanium dioxide and silica dioxide nanoparticles compared to the dental disinfectant chlorhexidine on Streptococcus mutans using a suite of bioassays, Nanotoxicology, 2014). In addition, in textiles and building materials, nano-silver coatings are used to develop antimicrobial fabrics or wall coatings to inhibit mold growth (Reference: Antimicrobial silver nanoparticles for wound healing application: progress and future trends, Materials, 2016).

[0006] Despite significant progress in existing nano-silver antibacterial coatings, several technical limitations remain. First, nano-silver particles are prone to aggregation and oxidation, leading to uneven coatings and reduced antibacterial performance. While nano-silver wires prepared using traditional hydrothermal methods offer controllable size, their lack of stable surface modification makes them susceptible to aggregation in humid and hot environments, affecting dispersion stability. For example, in aqueous systems, the low zeta potential of nano-silver particles makes them prone to sedimentation, causing coating defects (see patent CN1470574A). Second, poor adhesion between the coating and the substrate is another prominent issue. Many coatings employ simple doping methods, resulting in insufficient interfacial compatibility between nano-silver and polymer matrices (such as epoxy resins). After frequent rubbing or cleaning, they are easily peeled off, with adhesion reaching only below 3B (Reference: Nanomaterial-Based Antimicrobial Coating for Biomedical Implants: A Mini-Review, ACS Omega, 2022). In transparent applications, such as touch display modules, the introduction of nano-silver often reduces light transmittance (typically below 85%), affecting visual effects and touch sensitivity (Reference: Emerging technologies for long-term antimicrobial device coatings: advantages and limitations, Exp BiolMed, 2017).

[0007] Third, the release rate of silver ions is difficult to control precisely. Excessive initial release results in strong early antibacterial effects but poor persistence, while insufficient release in later stages fails to maintain long-term bactericidal efficacy. Simultaneously, high concentrations of silver ions may cause cytotoxicity or environmental pollution; the EU and other regions have established strict regulations on the use of nanosilver (Reference: Opinion on Nanosilver: safety, health and environmental effects and role in antimicrobial resistance, Scientific Committee on Emerging and Newly Identified Health Risks, 2014). Studies show that silver ions are the main source of toxicity in nanosilver; in some coatings, silver ion migration may lead to electrode failure or short circuits (Reference: Nanosilver / DCOIT-containing surface coating effectively and persistently reduce microbial load on hospital surfaces: a potential tool incombating healthcare-associated infections, J Hosp Infect, 2023). Furthermore, existing multilayer coating processes are complex, involving multiple synthesis steps and high-temperature processing, resulting in high costs and hindering large-scale production. For example, although plasma polymerization can embed silver nanoparticles, it requires sophisticated equipment and makes it difficult to control the coating thickness (Reference: Evaluating the antibacterial efficacy of a silver nanocomposite coating on titanium dental implants: An in vitro study, Nanotoxicology, 2024).

[0008] In composite materials, while the introduction of nanofillers such as hexagonal boron nitride or silica can enhance the wear resistance of coatings, the synergistic effect of these materials with nanosilver is limited in existing technologies, making it impossible to simultaneously optimize antibacterial, conductive, and transparent properties. For example, although traditional powder coatings add organic functionalized montmorillonite to achieve antibacterial properties, the lack of silver ions results in an antibacterial rate of less than 90%. Furthermore, in applications on flexible substrates, the coating is prone to cracking, with performance decreasing by more than 10% after 100,000 bending cycles (Reference: Advances in silver nanoparticles: a comprehensive review on their potential for antimicrobial applications, Front Microbiol, 2024). These limitations restrict the promotion of nanosilver antibacterial coatings in high-end fields, such as flexible touchscreens or smart wearable devices.

[0009] To address the aforementioned issues, there is an urgent need to develop a novel modified nano-antibacterial coating. This coating should achieve high dispersion stability of nano-silver, controlled silver ion release, high adhesion (≥5B), and high light transmittance (≥85%) through surface functionalization, three-dimensional network construction, and multilayer optimization, while ensuring a hardness ≥3H and an antibacterial rate ≥95%. Based on this background, this invention proposes a modified nano-antibacterial coating containing nano-silver and its preparation method, aiming to overcome the shortcomings of existing technologies and provide an efficient, durable, and multifunctional antibacterial solution. Summary of the Invention

[0010] To address the shortcomings of existing nano-silver antibacterial coatings, such as the tendency of nano-silver particles to agglomerate and settle, leading to uneven coating and unstable antibacterial effects; poor adhesion to the substrate resulting in easy detachment and peeling; low light transmittance affecting the display effect on transparent substrates such as touch display modules; difficulty in controlling the silver ion release rate leading to insufficient antibacterial durability and potential risks of cytotoxicity or bacterial resistance; and the complexity, high cost, and poor compatibility of multilayer coating processes, this invention provides a modified nano-antibacterial coating containing nano-silver and its preparation method. This method achieves high dispersion stability of nano-silver, controlled silver ion release, high adhesion, and high light transmittance through surface modification of nano-silver wires, construction of a three-dimensional synergistic network, multilayer composite structure, and microstructure optimization, while ensuring efficient and durable antibacterial performance. It is suitable for touch display module surfaces, providing an integrated solution of "antibacterial + transparency + wear resistance."

[0011] The present invention adopts the following technical solution: a method for preparing a modified nano-antibacterial coating containing nano-silver, comprising the following steps by weight: (1) preparation of modified nano-silver wire sol: silver nitrate (CAS No.: 7761-88-8), polyvinylpyrrolidone (CAS No.: 9003-39-8), p-phenylenediamine (CAS No.: 106-50-3), isophthaloyl chloride (CAS No.: 99-63-8) and ferric chloride hexahydrate (CAS No.: 10025-77-1) in a mass ratio of (8-15): (3- 7): (1-5): (1-5): (0.05-0.2) are mixed, and 100-200 parts of deionized water are added as a solvent. The mixture is then subjected to hydrothermal reaction at 120-180℃ for 1-4 hours to obtain silver nanowires (AgNW, length 30-50μm, diameter 20-40nm). Electrochemical etching is then performed, followed by redispersing the etched silver nanowires in a 2-10wt% aqueous solution of polyethyleneimine (CAS No.: 9002-98-6). Ultrasonic dispersion is then performed (power 200-600W, frequency 20-60kHz). (1) Time 30-60 min) to obtain modified silver nanowire sol; (2) Construction of synergistic network structure: Polyacrylonitrile powder (CAS No.: 25014-41-9) was dissolved in 6-10 times its mass of N,N-dimethylformamide (CAS No.: 68-12-2), and magnetically stirred at 120-160 rpm at 60-80℃ until completely dissolved to form a spinning solution. Then electrospinning was performed (voltage 10-20kV, flow rate 0.5-2mL / h, needle inner diameter 0.5mm, receiving distance 10-20cm) to form a thickness Nanofiber membranes with a diameter of 5-10 μm and a diameter of 200-500 nm were obtained, and then hot-pressed at 80-120℃ for 5-15 min to reduce the fiber diameter to 200-300 nm and the membrane porosity to be greater than 80%, thus obtaining a polyacrylonitrile nanofiber membrane. The membrane was then immersed in a 5-15 wt% ethylenediamine (CAS No.: 107-15-3) solution (temperature 60-80℃, time 2-6 h), removed, and dried at a low temperature of 40-50℃. The modified silver nanowire sol obtained in step (1) was then applied at a rate of 0.1-0.5 mL / m 2Sprayed onto a polyacrylonitrile nanofiber membrane and dried at 90-100℃, a polyacrylonitrile membrane with a synergistic network structure containing silver nanofibers is obtained, wherein the silver nanofibers form a three-dimensional cross-linked network with the fibers to improve conductivity and antibacterial efficiency; (3) Spin coating treatment: Lithium fluoride (CAS No.: 7789-24-4) is dissolved in ethanol (CAS No.: 64-17-5) to prepare a 1-5wt% solution, and spin-coated at 2000-4000rpm for 30-45s onto the polyacrylonitrile membrane with the synergistic network structure obtained in step (2), and then... Baking at 120-180℃ for 30-60 min yields a spin-coated film with a thickness of 0.5-2 μm, wherein the lithium fluoride layer provides surface modification to enhance the adhesion of subsequent layers; (4) Construction of nanolayers: Hexagonal boron nitride nanosheets (CAS No.: 10043-11-5, sheet diameter 50-200 nm, thickness 1-5 nm) and polyetherimide (CAS No.: 61128-46-9) are mixed at a mass ratio of 1:(0.5-2) and dispersed in N-methylpyrrolidone (CAS No.: 872-50-4) to prepare a concentrated solution. A slurry with a thickness of 10-20 wt% is applied to the spin-coated film obtained in step (3) with a thickness of 0.5-1 μm, a gap of 10-50 μm, and a speed of 0.1-1 m / min. The film is then dried at 70-80℃ for 1-2 h to obtain a spin-coated film containing a nanolayer. (5) Surface treatment: Bisphenol F type epoxy resin (CAS No.: 28064-14-4) is spin-coated onto the spin-coated film containing a nanolayer obtained in step (4) at 2000-4000 rpm to form a coating with a thickness of 50-100 μm. The coating is then cured at 150-200℃ for 2- After 6 hours, a spin-coated film with a release layer was obtained, wherein the epoxy resin layer enhances the surface wear resistance and release protection; (6) Microstructure optimization treatment: The spin-coated film with a release layer obtained in step (5) was immersed in a 0.2-1wt% potassium hydroxide (CAS No.: 1310-58-3) solution for wet micro-etching (temperature 40-60℃, stirring speed 100-200rpm, time 5-20min), and then washed with deionized water, dried with nitrogen and dried at 50℃ for 2-10min to obtain a modified nano antibacterial coating containing nano silver.

[0012] Preferably, in step (1), the mass ratio of silver nitrate, polyvinylpyrrolidone, p-phenylenediamine, isophthaloyl chloride, and ferric chloride hexahydrate is (10-12):(4-6):(2-4):(2-4):(0.1-0.15); the hydrothermal reaction temperature in step (1) is 120-180℃ and the time is 1-4h; the electrochemical etching voltage in step (1) is 0.5-2V and the current density is 1-5mA / cm. 2 The time is 10-60s; the concentration of the polyethyleneimine aqueous solution is 4-8wt%; the ultrasonic dispersion power in step (1) is 300-500W, the frequency is 30-50kHz, and the time is 40-50min.

[0013] Preferably, in step (2), the polyacrylonitrile powder is dissolved in N,N-dimethylformamide at a mass ratio of 7-9 times; the stirring temperature is 65-75℃ and the rotation speed is 130-150 rpm; the electrospinning voltage is 12-18 kV, the flow rate is 1-1.5 mL / h, and the receiving distance is 12-18 cm; the hot pressing temperature is 90-110℃ and the time is 8-12 min; the concentration of the ethylenediamine solution is 8-12 wt%, the immersion temperature is 65-75℃, and the time is 3-5 h; the low-temperature drying temperature is 42-48℃; and the spraying amount is 0.2-0.4 mL / m. 2 The high-temperature drying temperature is 92-98℃.

[0014] Preferably, in step (3), the concentration of the lithium fluoride solution is 2-4 wt%; the spin coating speed is 2500-3500 rpm and the time is 35-40 s; the baking temperature is 140-160℃ and the time is 40-50 min.

[0015] Preferably, in step (4), the mass ratio of hexagonal boron nitride nanosheets to polyetherimide is 1:(1-1.5); the slurry concentration is 12-18wt%; the coating thickness is 0.6-0.9μm, the gap is 20-40μm, the speed is 0.2-0.8m / min; the drying temperature is 72-78℃, and the time is 1.2-1.8h.

[0016] Preferably, in step (5), the spin coating speed is 2500-3500 rpm; the coating thickness is 60-90 μm; the curing temperature is 160-190℃ and the time is 3-5 h.

[0017] Preferably, in step (6), the concentration of potassium hydroxide solution is 0.3-0.8 wt%; the micro-etching temperature is 45-55℃, the stirring speed is 120-180 rpm, the time is 8-15 min, and the drying time is 4-8 min.

[0018] Preferably, the modified nano-antibacterial coating has a thickness of 100-200μm, a light transmittance of ≥85%, an adhesion of ≥5B, and a hardness of ≥3H, and is suitable for the surface of touch display modules.

[0019] A modified antibacterial nanocoating containing silver nanoparticles, wherein the modified antibacterial nanocoating containing silver nanoparticles is obtained by the preparation method described above.

[0020] Compared to existing technologies, this invention improves the dispersion stability and antioxidant capacity of silver nanowires in sol by modifying the surface of polyethyleneimine, avoiding the problems of easy aggregation and sedimentation of traditional silver nanowires. A three-dimensional porous network of polyacrylonitrile nanofibers is constructed through electrospinning and hot pressing, forming a synergistic cross-linked structure with the modified silver nanowires. This not only enhances conductivity and mechanical strength but also achieves uniform distribution and controlled release of silver ions, significantly improving antibacterial durability. A lithium fluoride interface layer is introduced to enhance multilayer adhesion, hexagonal boron nitride nanosheets provide thermal barrier protection and synergistic physical antibacterial properties, a bisphenol F epoxy resin protective layer improves wear resistance, and wet micro-etching optimizes the surface microstructure to increase the contact area for sterilization. The overall coating exhibits an antibacterial rate of ≥95% against Staphylococcus aureus and Escherichia coli, a light transmittance of ≥85%, adhesion of ≥5B, hardness of ≥3H, and a performance change of <10% after 100,000 flexural cycles. The process is simple and low-cost, making it suitable for medical equipment, touch displays, and public terminals, promoting the upgrading of the antibacterial materials industry.

[0021] Specifically, this invention achieves a significant breakthrough in the preparation and modification of silver nanowires. In existing technologies, silver nanowires are often synthesized via hydrothermal methods, but the synthesized nanowires lack a protective layer on their surface and are prone to aggregation in aqueous or organic solvents. This is because silver nanowires have high surface energy, leading to self-aggregation dominated by van der Waals forces, resulting in uneven distribution and affecting the antibacterial uniformity and stability of the coating. This invention introduces polyethyleneimine (PEI) as a surface modifier, achieving amino functionalization of the silver nanowire surface through an electrochemical etching followed by redispersion. Polyethyleneimine is a cationic polymer rich in amino (-NH2) and imine (-NH-) groups on its molecular chain. These groups can form coordination bonds or electrostatic adsorption with the surface of silver nanowires, forming a dense protective shell. This shell not only increases the zeta potential of the silver nanowires (typically from -20mV to over +40mV), enhances electrostatic repulsion, and prevents interparticle aggregation, but also blocks oxygen and moisture from contacting the silver surface, reducing oxidation reactions. Compared to traditional methods (such as simply adding surfactants), the modification method of this invention is more stable. After ultrasonic dispersion, the sol can be stored stably for several months without settling, and the antibacterial efficacy is extended to more than one year. Simultaneously, the addition of p-phenylenediamine and isophthaloyl chloride as structure-directing agents in the hydrothermal reaction synergistically regulates the growth path of the silver nanowires with ferric chloride hexahydrate, ensuring a uniform morphology of 30-50 μm in length and 20-40 nm in diameter. This size control mechanism is based on a nucleation-growth model: ferric chloride acts as an oxidant to promote the slow reduction of silver ions, p-phenylenediamine provides amino complexation, and isophthaloyl chloride introduces chloride ions to regulate crystal facet growth, avoiding the defect of wide diameter distribution (>50 nm variation) of silver wires in existing technologies, thereby improving the uniformity of silver ion release.

[0022] In constructing the collaborative network structure, this invention innovatively combines electrospun polyacrylonitrile (PAN) nanofiber membranes with modified silver nanowires to form a three-dimensional cross-linked network, solving the problems of unstable silver nanofiber loading and uncontrolled release in existing coatings. Existing technologies often employ planar coating or simple impregnation, resulting in silver nanofibers remaining only on the surface, easily detached by friction, and exhibiting explosive silver ion release (high initially, low later), leading to poor antibacterial durability (see patent: CN109517206A). This invention first prepares PAN nanofiber membranes with a diameter of 200-500 nm through electrospinning, which possess a high specific surface area (>100m²). 2 The PAN fibers, with a porous structure (porosity > 80%), are further compressed to 200-300 nm using hot-pressing, enhancing mechanical strength and pore connectivity. Subsequently, ethylenediamine impregnation introduces amine functional groups, giving the PAN fiber surface a positive charge, which then forms a tight cross-link with the modified silver nanowires (negatively charged surface) through electrostatic self-assembly. After spraying the silver nanowire sol, high-temperature drying promotes hydrogen bonding and van der Waals force curing, forming a composite structure where silver nanowires are embedded in the fiber network. This three-dimensional network mechanism resembles a "spider web" trapping model: the silver nanowires are uniformly anchored at fiber intersections, preventing migration; the porous structure provides silver ion diffusion channels, achieving slow release (release rate controlled at 0.1-1 ppm / h), avoiding initial overload-induced toxicity. Simultaneously, this network improves the coating's conductivity (sheet resistance < 50 Ω / sq), making it suitable for touch display modules and achieving a dual function of "antibacterial + conductive". Compared to existing two-dimensional coatings, the bending durability of the network structure of this invention is improved by 30%, and the silver wire breakage rate is less than 5% after 100,000 folds.

[0023] Spin-coating introduces a lithium fluoride layer as an interface modifier, further optimizing the adhesion of the multilayer structure. In existing coatings, the interface between the polymer substrate and the inorganic nanolayer is incompatible, often leading to delamination (adhesion <4B). Lithium fluoride (LiF) is an amphiphilic compound that, after being dissolved in ethanol, is spin-coated to form a thin film (0.5-2 μm). The baking process promotes the crystallization of LiF and its formation of hydrogen and ionic bonds with the PAN network. This layer mechanism is based on surface energy matching: LiF reduces the surface energy of the substrate (from 40 mJ / m²). 2 Reduced to 25 mJ / m 2 This enhances the wettability and bonding strength with subsequent organic layers. Tests show that the coating adhesion of this invention reaches 5B, which is far superior to the prior art (Reference: Antibacterial activity of nanosilver ions and particles, Nano Letters, 2010).

[0024] In the construction of the nanolayer, the composite of hexagonal boron nitride (h-BN) nanosheets and polyetherimide (PEI) provides a thermal barrier and synergistic antibacterial properties. Existing coatings have poor heat resistance, and silver oxidation is accelerated at high temperatures. The h-BN nanosheets of this invention (50-200 nm in diameter, 1-5 nm in thickness) have a layered structure and high thermal conductivity (>200 W / m·K). After coating, they form a "brick wall" barrier, blocking heat conduction and oxygen permeation, and protecting the stability of the silver nanowires. At the same time, the sharp edges of h-BN can physically cut bacterial cell membranes, synergistically killing bacteria with silver ions (increasing the antibacterial rate by 15%). Polyetherimide acts as a binder to ensure uniform dispersion, and the slurry coating parameters optimize the layer thickness and gaps, avoiding light scattering that affects light transmittance.

[0025] The surface treatment uses bisphenol F type epoxy resin spin-coating and curing to form a wear-resistant protective layer. Existing coatings have low hardness (<2H) and are easily scratched and peeled off. The epoxy resin of this invention forms a dense network through a cross-linking reaction, achieving a hardness of 4H or higher and a coefficient of friction of <0.3. The curing mechanism involves ring-opening polymerization of epoxy groups, forming a high cross-linking density, which improves chemical resistance and mechanical properties.

[0026] Microstructure optimization was achieved through wet etching with potassium hydroxide to create surface micro-nano roughness (Ra 0.1-1 μm), increasing the bacterial contact area and promoting silver ion adsorption. The etching mechanism involves selectively etching the organic layer to expose the ends of the silver nanowires, enabling controlled release (extending the release period by 2 times).

[0027] Overall, the multi-layer composite mechanism of this invention ensures synergistic performance: antibacterial rate ≥95% (GB / T 21866-2008), light transmittance ≥85% (wavelength 550nm), adhesion ≥5B (ASTM D3359), hardness ≥3H (GB / T 6739-2006), and excellent abrasion resistance (Taber wear <0.3). Compared with existing technologies, the cost is reduced by 20%, the process is simplified by 30%, and it is suitable for touch screens (thickness <200μm, good flexibility), promoting industrial application and contributing to public health protection. Attached Figure Description

[0028] Figure 1 This is a scanning electron microscope image of the modified silver nanowire sol prepared in Example 1.

[0029] Figure 2 This is the infrared spectrum of the modified silver nanowire sol prepared in Example 1.

[0030] Figure 3 This is a scanning electron microscope image (scale bar 50 μm) of the polyacrylonitrile film containing a silver nanoparticle synergistic network structure prepared in Example 1.

[0031] Figure 4 The image shows the infrared spectrum of the polyacrylonitrile film containing a nano-silver synergistic network structure prepared in Example 1.

[0032] Figure 5 This is a scanning electron microscope image of the antibacterial effect of the modified nano-antibacterial coating containing nano-silver prepared in Example 1 on Staphylococcus aureus.

[0033] Figure 6 This is a scanning electron microscope image of the antibacterial effect of the modified nano-antibacterial coating containing nano-silver prepared in Example 1 on Escherichia coli. Detailed Implementation

[0034] The present invention will now be described in detail through specific embodiments. However, these illustrative embodiments are for purposes and uses only to illustrate the invention and do not constitute any limitation on the actual scope of protection of the invention, nor are they intended to restrict the scope of protection of the invention to these embodiments. For parameter ranges not mentioned, intermediate values ​​are selected. Also, for mass ratios not explicitly stated or mentioned, the mass ratio after addition generally refers to the mass ratio. Furthermore, in the present invention, the unit of mass is grams (g).

[0035] Example 1 The preparation method of modified nano-antibacterial coating containing nano-silver includes the following steps: (1) Preparation of modified nano-silver wire sol: silver nitrate, polyvinylpyrrolidone, p-phenylenediamine, isophthaloyl chloride and ferric chloride hexahydrate are mixed in a mass ratio of 10:5:3:3:0.1 (total mass 21.1g, i.e., 10g silver nitrate, 5g polyvinylpyrrolidone, 3g p-phenylenediamine, 3g isophthaloyl chloride and 0.1g ferric chloride hexahydrate), and 150 parts of deionized water (150g) are added as solvent. The mixture is subjected to hydrothermal reaction at 150℃ for 2.5h to obtain nano-silver wire (40μm in length and 30nm in diameter). Then, electrochemical etching is performed (voltage 1V, current density 3mA / cm). 2 The etching time was 30 s. The etched silver nanowires were then redispersed in a 6 wt% polyethyleneimine aqueous solution (the total mass of the polyethyleneimine solution was adjusted according to the mass of the silver nanowires to ensure a concentration of 6 wt%). The modified silver nanowire sol was obtained by ultrasonic dispersion (400 W power, 40 kHz frequency, 45 min). The scanning electron microscope image is shown below. Figure 1 As shown, its infrared spectrum is as follows Figure 2As shown; (2) Construction of the synergistic network structure: Polyacrylonitrile powder was dissolved in 8 times its mass of N,N-dimethylformamide (assuming 50g of polyacrylonitrile powder, then 400g of N,N-dimethylformamide), and magnetically stirred at 140rpm at 70℃ until completely dissolved to form a spinning solution. Then, electrospinning was performed (voltage 15kV, flow rate 1.2mL / h, needle inner diameter 0.5mm, receiving distance 15cm) to form a nanofiber membrane with a thickness of 7.5μm and a diameter of 350nm. Subsequently, it was hot-pressed at 100℃ for 10min to reduce the fiber diameter to 250nm and the membrane porosity to be greater than 80%, thus obtaining a polyacrylonitrile nanofiber membrane. Then, the membrane was immersed in a 10wt% ethylenediamine solution (temperature 70℃, time 4h), and after being taken out, it was dried at a low temperature of 45℃. Then, the modified silver nanowire sol obtained in step (1) was used at 0.3mL / m 2 Spraying the coating onto a polyacrylonitrile nanofiber membrane and drying it at 95℃ yields a polyacrylonitrile membrane containing a synergistic network structure of silver nanoparticles. Its scanning electron microscope image is shown below. Figure 3 As shown, its infrared spectrum is as follows Figure 4 As shown; (3) Spin coating: Lithium fluoride was dissolved in ethanol to prepare a 3wt% solution, and spin-coated at 3000 rpm for 37s onto the polyacrylonitrile film with the synergistic network structure obtained in step (2), and baked at 150℃ for 45min to obtain a spin-coated film with a thickness of 1.2μm; (4) Construction of nanolayers: Hexagonal boron nitride nanosheets (100nm in diameter and 3nm in thickness) and polyetherimide were mixed at a mass ratio of 1:1.2 and dispersed in N-methylpyrrolidone to prepare a 15wt% slurry (assuming a total slurry of 100g, then the total mass of hexagonal boron nitride nanosheets and polyetherimide is 15g), with a thickness of 0.75μm, a gap of 30μm, and a speed of 0.5m / min. n is coated onto the spin-coated film obtained in step (3), and dried at 75°C for 1.5h to obtain a spin-coated film containing a nano-layer; (5) Surface treatment: Bisphenol F type epoxy resin is spin-coated onto the spin-coated film containing a nano-layer obtained in step (4) at 3000rpm to form a coating with a thickness of 75μm, and cured at 175°C for 4h to obtain a spin-coated film containing a release layer; (6) Microstructure optimization treatment: The spin-coated film containing a release layer obtained in step (5) is immersed in a 0.5wt% potassium hydroxide solution for wet micro-etching (temperature 50°C, stirring speed 150rpm, time 12min), then washed with deionized water, dried with nitrogen, and dried at 50°C for 6min to obtain a modified nano antibacterial coating containing nano silver. The obtained coating has a thickness of 150μm, a light transmittance of 88%, an adhesion of 5B, and a hardness of 4H.

[0036] The specific parameters for Examples 2-9 and Comparative Examples 1-9 are listed in the following tables. The tables are designed separately for each step, with each table listing only the parameter values ​​(including mass or weight units in g) that differ from those in Example 1; all other parameters are the same as in Example 1. The examples cover both endpoint and intermediate parameter values, while the comparative examples demonstrate disadvantages through the absence of key components, substitution with commonly used similar components, or parameters exceeding their range.

[0037] Table 1: Preparation parameters of modified silver nanowire sol in step (1)

[0038] Table 2: Construction parameters of the collaborative network structure in step (2)

[0039] Table 3: Spin coating parameters for step (3)

[0040] Table 4: Construction parameters of nanolayers in step (4)

[0041] Table 5: Surface treatment and microstructure optimization parameters for steps (5)-(6)

[0042] To verify the performance of the modified nano-antibacterial coating containing nano-silver described in this invention, multi-dimensional tests were conducted on the products prepared in Examples 1-9 and Comparative Examples 1-9. The tests included antibacterial performance (inhibition rate against Staphylococcus aureus ATCC25923 and Escherichia coli ATCC35218), light transmittance, adhesion, hardness, abrasion resistance (coefficient of friction), and thickness. The test methods are as follows: Antibacterial performance test: According to GB / T 21866-2008 standard, the shaking method was used. After the coating sample was in contact with the bacterial suspension for 24 hours, the bacterial count was performed, and the inhibition rate (%) was calculated. Light transmittance test: Measured using a UV-Vis spectrophotometer (wavelength 550nm) (%). Adhesion test: According to ASTM D3359 standard, the cross-cut test was used for evaluation (0-5B, 5B being optimal). Hardness test: According to GB / T 6739-2006 standard, the pencil hardness test was used. Abrasion resistance test: The coefficient of friction was measured using a Taber abrasion tester after a load of 500g and 1000 revolutions. Thickness test: The thickness was measured directly using a thickness gauge (μm).

[0043] Table 6: Performance Test Results

[0044] The test results show that the antibacterial rate of the products in the examples is ≥95.3%, the light transmittance is ≥85.2%, the adhesion is 5B, and the hardness is ≥3.5H, demonstrating excellent performance. In contrast, the comparative examples, due to the absence or substitution of key components or parameter deviations, showed a significant decrease in antibacterial rate (59.4-73.6%), light transmittance (71.6-79.2%), and adhesion (1-4B), indicating a substantial decline in performance. This demonstrates the superiority of the preparation method of this invention. Furthermore, taking Example 1 as an example... Figure 5 As shown, the Staphylococcus aureus on the coating surface exhibits abnormal morphology, with most having already broken through the membrane and decomposed. Meanwhile, as... Figure 6 As shown, E. coli exhibits a phenomenon of gigantism, caused by cell membrane rupture and water influx, and its outer surface shape is abnormal.

[0045] The performance test results (Table 6) of the modified nano-antibacterial coating containing nano-silver described in this patent show that the products of Examples 1-9 exhibit excellent performance in antibacterial properties (antibacterial inhibition rate ≥95.3%), optical properties (transmittance ≥85.2%), mechanical properties (adhesion 5B, hardness ≥3.5H, coefficient of friction ≤0.29), and structural integrity (thickness controlled between 102.7-198.6μm), far superior to Comparative Examples 1-9 (antibacterial inhibition rate 59.4-73.6%, transmittance 71.6-79.2%, adhesion 1-4B, hardness 0.8H-2.5H, coefficient of friction 0.46-0.61). This difference stems from the optimization of the preparation method mechanism: through surface-modified nano-silver wires (AgNW), three-dimensional synergistic network construction, multilayer interface enhancement, and microstructure optimization, high dispersion stability of nano-silver, controlled release of silver ions, interfacial compatibility, and surface durability are achieved. The following analysis, based on the core mechanisms described in the patent (such as zeta potential enhancement, electrostatic self-assembly, thermal barrier shielding, and selective etching), provides an in-depth understanding of the test results. The analysis will be divided into example groups and comparative groups, focusing on the causal relationships of key performance indicators.

[0046] The parameters in Examples 1-9 are all within the optimized range, reflecting the synergistic effect of the multi-step process mechanism. The core mechanisms include: (1) Polyethylene imine (PEI) surface modification increases the zeta potential of AgNW (above +40mV), enhancing electrostatic repulsion and anti-oxidation; (2) Polyacrylonitrile (PAN) nanofiber three-dimensional network anchors AgNW through electrostatic self-assembly, achieving slow release of silver ions (0.1-1ppm / h); (3) Lithium fluoride (LiF) interface layer reduces surface energy (25mJ / m). 2(3) Bridging the organic-inorganic interface; (4) The “brick wall” structure of hexagonal boron nitride (h-BN) nanosheets provides thermal barrier and physical cutting antibacterial properties; (5) The highly cross-linked network of bisphenol F epoxy resin enhances wear resistance; (6) Potassium hydroxide (KOH) wet micro-etching creates micro-nano roughness (Ra 0.1-1μm), increasing the contact sterilization area. These mechanisms ensure uniform release of silver ions, multilayer stability of the coating, and surface functionalization, resulting in a comprehensive improvement in performance.

[0047] Antibacterial performance (inhibition rate): The examples showed high inhibition rates against Staphylococcus aureus (95.3-99.4%) and Escherichia coli (96.1-99.8%), attributed to the synergistic antibacterial mechanism of AgNW and h-BN. AgNW releases Ag+, disrupting bacterial cell membranes and DNA replication, while h-BN's sharp edges physically cut the cell wall, resulting in a synergistic effect that enhances the inhibition rate by 15%. The three-dimensional network controls the sustained release of Ag+, avoiding initial bursts (toxicity risk) and later attenuation (poor persistence). For example, Example 3 (high parameter endpoint) showed the highest inhibition rate (99.4% / 99.8%) due to the longer hydrothermal reaction time (4h), resulting in more uniform AgNW (50μm in length), enhancing release uniformity; Example 2 (low parameter endpoint) showed the lowest inhibition rate (95.3% / 96.1%), but still significantly exceeded the standard (≥95%), thanks to PEI modification preventing aggregation (zeta potential enhancement inhibits van der Waals aggregation).

[0048] Optical performance (transmittance): The transmittance of the examples is 85.2-90.8%, meeting the requirements of touch display (≥85%). The mechanism lies in the optimization of coating parameters (such as h-BN slurry concentration of 10-20wt%, thickness of 0.5-1μm) to avoid light scattering: the refractive index of the h-BN layered structure is matched (~2.0), which works synergistically with the PAN network (porosity >80%) to reduce interface reflection. Example 2 has the highest transmittance (90.8%) due to the low concentration slurry (10wt%) and thin layer (0.5μm) minimizing scattering; Example 3 has the lowest transmittance (85.2%) due to the thick layer (1μm) and high concentration (20wt%) slightly increasing light absorption, but it is still better than the prior art (<85%), thanks to the enhanced wettability of the LiF layer and uniform coating.

[0049] Mechanical properties (adhesion, hardness, coefficient of friction): Adhesion is 5B across the board, hardness ranges from 3.5H to 4.5H, and coefficient of friction ranges from 0.21 to 0.29, reflecting a multi-layer interface mechanism. LiF bridging bonds (hydrogen bonds / ionic bonds) match surface energy, epoxy resin has high crosslinking density (ring-opening polymerization forms a network), and h-BN provides thermal barrier stress. Example 3 has the highest hardness (4.5H) due to its long curing time (6h) which increases the degree of crosslinking, and the lowest coefficient of friction (0.21) because the micro-etching roughness increases without compromising overall density. Example 2 has the lowest hardness (3.5H), but still meets the standard, thanks to the hot-pressing treatment that compresses the fibers (diameter 200-300nm), enhancing network strength and improving bending durability by 30%.

[0050] Thickness control: The thickness is 102.7-198.6 μm, which is positively correlated with the spin coating / coating parameters (such as 198.6 μm in Example 3 due to the high spin speed of 4000 rpm and the thick coating of 100 μm), but the mechanism ensures uniformity (no defects) and does not affect other properties.

[0051] Overall, the implementation examples demonstrate balanced performance, with the intermediate parameter values ​​(such as in Example 1) being optimal, and the endpoint values ​​(such as in Examples 2 / 3) validating the robustness of the range. This proves that the mechanisms (such as the sustained-release model and interface bridging) are effective in practical applications, promoting antibacterial durability (>1 year) and multifunctional integration.

[0052] Comparative Examples 1-9 exhibited a comprehensive performance degradation due to the disruption of mechanistic balance caused by the absence of key components, substitution of analogues, or parameters exceeding the range. The core issues are: lack of modification leads to AgNW aggregation (low zeta potential), network instability (no self-assembly), interface incompatibility (no bridging), and uncontrolled release (burst-like), amplifying problems such as oxidation, stripping, and light scattering.

[0053] Comparative Example 1 (lacking ferric chloride hexahydrate): Antibacterial rate 72.4% / 74.1%, light transmittance 78.3%, adhesion 3B, hardness 2H, coefficient of friction 0.48. Mechanism analysis: Ferric chloride acts as an oxidant to regulate AgNW growth (nucleation-growth model). Its absence leads to uneven silver wire morphology (diameter variation > 50 nm) and uneven Ag release. + Initially too rapid (high toxicity), later insufficient; without regulation, high surface energy promotes aggregation, increases coating defects, light scattering, and peeling.

[0054] Comparative Example 2 (p-phenylenediamine replaced with aniline): Antibacterial rate 68.9% / 70.5%, light transmittance 76.7%, adhesion 3B, hardness 1.5H, coefficient of friction 0.52. Mechanism analysis: p-phenylenediamine provides amino complexation to regulate crystal facet growth, while aniline has weak complexation (no para structure), leading to uneven AgNW (short length <30μm) and uncontrolled silver ion release; poor complexation weakens the PEI modification effect, resulting in low zeta potential, increased agglomeration, poor interfacial compatibility, and decreased hardness.

[0055] Comparative Example 3 (silver nitrate and other components at a mass ratio below the range): Antibacterial rate 65.3% / 67.8%, light transmittance 75.1%, adhesion 2B, hardness 1H, coefficient of friction 0.55. Mechanism analysis: Low proportion of silver source reduces AgNW yield, resulting in low density (<30% coverage) and weak antibacterial properties; low reducing agent (polyvinylpyrrolidone) leads to insufficient growth, numerous surface defects, accelerated oxidation, and unstable release; insufficient network load results in weak mechanical strength and easy peeling.

[0056] Comparative Example 4 (mass ratio exceeding the range): Antibacterial rate 61.7% / 63.2%, light transmittance 73.9%, adhesion 2B, hardness 1.2H, coefficient of friction 0.58. Mechanism analysis: Excessive proportion leads to oversaturation, resulting in coarse AgNW (diameter > 40nm), strong light scattering, and low light transmittance; excessive ferric chloride leads to over-oxidation, resulting in a thick surface oxide layer, Ag... + Release inhibition, poor antibacterial properties; high density causes aggregation, high interfacial stress, and low adhesion.

[0057] Comparative Example 5 (N,N-dimethylformamide concentration below the range): Antibacterial rate 70.8% / 72.6%, light transmittance 77.4%, adhesion 3B, hardness 2.2H, coefficient of friction 0.50. Mechanism analysis: Low solvent concentration spinning solution has high viscosity, coarse fiber diameter (>500nm), low porosity (<80%), and poor network connectivity; AgNW anchoring is weak, migration is easy, and release is uncontrolled; insufficient porosity increases light absorption and reduces light transmittance.

[0058] Comparative Example 6 (spinning solution ratio exceeding the range): Antibacterial rate 67.2% / 69.1%, light transmittance 74.8%, adhesion 2B, hardness 1.8H, coefficient of friction 0.53. Mechanism analysis: High solvent ratio spinning solution is thin, resulting in fine and weak fibers (easily broken) and low network strength; insufficient compression after hot pressing leads to pore collapse, AgNW shedding, and a decrease in antibacterial and mechanical properties.

[0059] Comparative Example 7 (without ethylenediamine immersion): Antibacterial rate 73.6% / 75.4%, light transmittance 79.2%, adhesion 4B, hardness 2.5H, coefficient of friction 0.46. Mechanism analysis: Ethylenediamine introduces positively charged amine groups, promoting electrostatic self-assembly; the absence of ethylenediamine results in a neutral PAN surface, with no anchoring of AgNW and weak cross-linking; the release is explosive, resulting in poor antibacterial durability, but slightly higher adhesion (no additional interfacial stress).

[0060] Comparative Example 8 (Lithium Fluoride Defect): Antibacterial rate 59.4% / 61.8%, light transmittance 71.6%, adhesion 1B, hardness 0.8H, coefficient of friction 0.61. Mechanism analysis: LiF bridging is missing, surface energy mismatch (40mJ / m²). 2 Multi-layer peeling; no wetting enhancement, uneven coating, many defects, aggravated light scattering and oxidation, and the worst performance.

[0061] Comparative Example 9 (Lithium fluoride concentration exceeding the range): Antibacterial rate 64.1% / 66.7%, light transmittance 72.9%, adhesion 2B, hardness 1.4H, coefficient of friction 0.56. Mechanism analysis: Excessively high concentration of LiF crystals results in excessive thickness (>2μm), increasing stress and scattering; excessive crystallization hinders Ag+ diffusion, weakening antibacterial properties; uneven interface makes peeling easy.

[0062] The comparative studies showed a significant decrease in performance (20-40% reduction in antibacterial rate and 10-15% reduction in light transmittance), confirming that the lack of a mechanism (such as the absence of oxidation regulation or interfacial bridging) amplifies the limitations of nano-silver (aggregation, oxidation, and exfoliation), leading to coating failure.

[0063] Test results confirm that the mechanisms of this invention (such as surface functionalization, three-dimensional networks, interface bridging, and micro-etching optimization) significantly improve coating performance, with the examples outperforming the comparative examples, addressing the pain points of existing technologies (easy aggregation, poor adhesion, and low light transmittance). This not only verifies the effectiveness of the parameter range but also provides guidance for antibacterial coating design: emphasizing synergistic effects and avoiding bias from single components. In the future, it can be extended to the field of flexible electronics, driving industrial upgrading.

[0064] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection defined by the claims submitted herein.

Claims

1. A method for preparing a modified nano-antibacterial coating containing nano-silver, characterized in that: The process, by weight, includes the following steps: (1) Silver nitrate, polyvinylpyrrolidone, p-phenylenediamine, isophthaloyl chloride, and ferric chloride hexahydrate are mixed in a mass ratio of (8-15):(3-7):(1-5):(1-5):(0.05-0.2), and 100-200 parts of deionized water are added. A hydrothermal reaction is performed to obtain silver nanowires. Then, electrochemical etching is performed, and the etched silver nanowires are redispersed in a 2-10 wt% polyethyleneimine aqueous solution. The modified silver nanowire sol is obtained by ultrasonic dispersion. (2) Polyacrylonitrile powder is dissolved in 6-10 times its mass of N,N-dimethylformamide, and magnetic stirring is performed to form a spinning solution. Then, electrospinning is performed to form a nanofiber membrane, followed by hot pressing to obtain a polyacrylonitrile nanofiber membrane. The membrane is then immersed in a 5-15 wt% ethylenediamine solution, removed, and dried at low temperature. The modified silver nanowire sol obtained in step (1) is then dispersed at 0.1-0.5 mL / m 2 (2) Spraying onto a polyacrylonitrile nanofiber membrane and drying at high temperature to obtain a polyacrylonitrile membrane with a synergistic network structure containing nanosilver; (3) Dissolving lithium fluoride in ethanol to prepare a solution with a concentration of 1-5wt%, spin coating onto the polyacrylonitrile membrane with a synergistic network structure obtained in step (2), and baking to obtain a spin-coated membrane; (4) Mixing hexagonal boron nitride nanosheets and polyetherimide at a mass ratio of 1:(0.5-2), dispersing them in N-methylpyrrolidone to prepare a slurry with a concentration of 10-20wt%, coating it onto the spin-coated membrane obtained in step (3), and drying to obtain a spin-coated membrane with a nanolayer; (5) Spin coating bisphenol F type epoxy resin onto the spin-coated membrane with a nanolayer obtained in step (4) to form a coating layer, and curing to obtain a spin-coated membrane with a release layer; (6) Immersing the spin-coated membrane with a release layer obtained in step (5) into a 0.2-1wt% potassium hydroxide solution for wet micro-etching, then washing with deionized water, blowing with nitrogen and drying to obtain a modified nano antibacterial coating containing nanosilver.

2. The method for preparing the modified nano-antibacterial coating containing nano-silver according to claim 1, characterized in that: In step (1), the mass ratio of silver nitrate, polyvinylpyrrolidone, p-phenylenediamine, isophthaloyl chloride, and ferric chloride hexahydrate is (10-12):(4-6):(2-4):(2-4):(0.1-0.15); the hydrothermal reaction temperature in step (1) is 120-180℃, and the time is 1-4h; the voltage of electrochemical etching in step (1) is 0.5-2V, and the current density is 1-5mA / cm. 2 The time is 10-60s; the concentration of the polyethyleneimine aqueous solution is 4-8wt%; the ultrasonic dispersion power in step (1) is 200-600W, the frequency is 20-60kHz, and the time is 30-60min.

3. The method for preparing the modified nano-antibacterial coating containing nano-silver according to claim 1, characterized in that: The parameters for magnetic stirring in step (2) are as follows: stirring temperature is 60-80℃, and rotation speed is 120-160rpm; the voltage for electrospinning in step (2) is 10-20kV, the flow rate is 0.5-2mL / h, and the receiving distance is 10-20cm; the temperature for hot pressing in step (2) is 80-120℃, and the time is 5-15min; the immersion temperature in step (2) is 60-80℃, and the time is 2-6h; the low-temperature drying temperature in step (2) is 40-50℃; and the high-temperature drying temperature in step (2) is 92-98℃.

4. The method for preparing the modified nano-antibacterial coating containing nano-silver according to claim 1, characterized in that: In step (3), the spin coating speed is 2000-4000 rpm and the time is 30-45s; the baking temperature is 120-180℃ and the time is 30-60min.

5. The method for preparing the modified nano-antibacterial coating containing nano-silver according to claim 1, characterized in that: In step (4), the coating thickness is 0.5-1μm, the gap is 10-50μm, and the speed is 0.1-1m / min; in step (4), the drying temperature is 70-80℃ and the time is 1-2h.

6. The method for preparing the modified nano-antibacterial coating containing nano-silver according to claim 1, characterized in that: In step (5), the spin coating speed is 2000-4000 rpm; the coating thickness is 60-90 μm; the curing temperature in step (5) is 150-200℃ and the time is 2-6 h.

7. The method for preparing the modified nano-antibacterial coating containing nano-silver according to claim 1, characterized in that: In step (6), the micro-etching temperature is 40-60℃, the stirring speed is 100-200rpm, and the time is 5-20min; in step (6), the drying temperature is 50℃ and the drying time is 2-10min.

8. The method for preparing the modified nano-antibacterial coating containing nano-silver according to claim 1, characterized in that: The modified nano-antibacterial coating has a thickness of 100-200μm, a light transmittance of ≥85%, an adhesion of ≥5B, and a hardness of ≥3H.

9. A modified nano-antibacterial coating containing nano-silver, characterized in that: The modified antibacterial nanocoating containing nano-silver is obtained by the preparation method described in any one of claims 1-8.

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