Low temperature synthesis of long-lasting, self-cleaning coatings

Abstract

The application discloses a low-temperature synthesis method of a long-acting self-sterilizing coating and belongs to the technical field of inorganic nano-coating low-temperature curing manufacturing. + -(Ti(O2)) 2‑ Preparation of a complex precursor solution; (2) spraying of the Ag + -(Ti(O2)) 2‑ complex precursor solution; (3) baking, curing and obtaining of a high-temperature-intolerant treatment substrate with a low-temperature deposited nano-silver-titanium dioxide coating by using the cured Ag + -(Ti(O2)) 2‑ complex precursor solution coating prepared in the above steps. The application breaks through the limitation that the traditional high-temperature thermal deposition titanium dioxide nano-coating technology cannot be applied to high-temperature-intolerant substrate materials, realizes low-temperature deposition of a nano-silver-titanium dioxide coating capable of absorbing visible light on the surface of a high-temperature-intolerant substrate material, and the low-temperature deposited nano-silver-titanium dioxide coating has a long-acting antibacterial self-sterilizing function on the surface of the substrate material.

Description

Technical Field

[0001] This invention relates to a low-temperature synthesis method for a long-lasting self-cleaning coating, belonging to the field of low-temperature curing manufacturing technology of inorganic nano-coatings. Background Technology

[0002] Typically, infections with viruses, especially coronaviruses, are likely to spread through physical contact and droplet transmission. Preventive healthcare is currently the only concrete option for limiting the ability of viruses to spread. Living and non-living surfaces play a crucial role in the spread of the novel coronavirus (Coronavirus Disease 2019, COVID-19) as well as more common viral and bacterial infections.

[0003] Surface disinfection plays a crucial role in strategies for preventing and controlling the spread of viruses. In most cases, applying the correct disinfection protocol is the only concrete option to limit the ability of viruses and bacteria to spread.

[0004] Chemical disinfectants (such as chlorine, peroxides, quaternary ammonium compounds, and alcohols) have been successfully used for the disinfection and sterilization of personal protective equipment and surfaces. Although chemical disinfectants have proven effective, they exhibit various drawbacks, such as the high concentrations required for 100% virus inhibition, limited effectiveness over time, and potential hazards, particularly in healthy environments like hospitals, including harmfulness, corrosiveness, and bacterial resistance.

[0005] Self-disinfecting surface coatings represent another powerful and promising method for preventing bacterial and viral contamination. Nanotechnology, self-disinfecting surfaces, and light-driven self-disinfection offer new perspectives. Photocatalytic disinfection, as an effective method for self-sterilizing various surfaces by continuously utilizing light energy to generate reactive oxygen species in situ under mild conditions, is highly competitive compared to harsh treatments (i.e., hot steam or corrosive chemicals such as sodium hypochlorite) and has attracted widespread attention.

[0006] The immobilization of photocatalytic coatings can be mainly divided into three categories based on the different interactions between titanium dioxide and the substrate material: thermal bonding (sol-gel, chemical vapor deposition, spray pyrolysis), physical deposition (physical vapor deposition, electrodeposition), and chemical bonding. Thermal bonding utilizes high temperatures (≥400℃) during the immobilization process to form chemical bonds between titanium dioxide and the substrate material during crystallization, achieving effective immobilization. Currently, it is mainly used on substrates with high heat resistance, such as zeolites and glass. Physical deposition utilizes magnetic and electric fields to deposit nano-titanium dioxide on different substrate surfaces, enabling high-quality photocatalytic coating processing. However, its high cost and limited processing area restrict its large-scale application. Chemical bonding uses organic binders such as polyvinyl alcohol and polyurethane to achieve the adhesion of nanoparticles to the substrate surface. However, the binder can cause an encapsulation effect, preventing titanium dioxide from contacting water, chemical molecules, and even toxic bacteria and contaminants. Furthermore, the photocatalytic free radical oxidation process can decompose the organic binder, leading to photocatalyst deactivation and detachment.

[0007] However, photocatalytic self-disinfection technology with nano-TiO2 as the main component faces two main challenges in practical applications. First, its absorption spectrum is biased towards the ultraviolet band, accounting for only 5% of the solar energy spectrum, which limits its performance in daily applications. Second, the "immobilization" of the catalyst on the substrate material is crucial, which means ensuring good adhesion between the catalyst and the substrate material. This ensures that the coating has stable catalytic activity over a long timescale and also prevents the shedding of nano-sized particles, thus avoiding potential health risks such as inhalation.

[0008] Therefore, addressing the two major challenges of photocatalytic self-disinfecting coatings—how to broaden the light absorption range of nano-titanium dioxide to achieve visible light-excited photocatalytic effects, and how to deposit nanocrystalline titanium dioxide at low temperatures on high-temperature-sensitive substrates to avoid damage to the substrate caused by high-temperature sintering—the design and synthesis of water-based Ag that can be in-situ photocured at low temperatures on textile surfaces is crucial. + -(Ti(O2)) 2- The low-temperature manufacturing of nano-Ag-TiO2 coatings with visible light absorption on the surface of nonwoven fabrics is achieved by using a complex precursor solution. This low-temperature curing self-disinfecting coating processing technology can achieve long-lasting antibacterial and purification functions on the surface of substrates that are not resistant to high temperatures, and can be processed in a large area at low cost. This has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0009] The purpose of this invention is to address two major challenges faced by photocatalytic self-disinfecting coatings: how to broaden the light absorption range of nano-titanium dioxide to achieve visible light-excited photocatalytic effects, and how to deposit nanocrystalline titanium dioxide at low temperatures on substrates that are not heat-resistant, avoiding damage to the substrate caused by high-temperature sintering. The invention designs and synthesizes water-based Ag that can be in-situ photocured at low temperatures on textile surfaces. +-(Ti(O2)) 2- By using a complex precursor solution, a nano-Ag-TiO2 coating with visible light absorption on the surface of nonwoven fabric can be manufactured at low temperature. This low-temperature curing self-disinfecting coating processing technology can achieve long-lasting antibacterial and purification functions on the surface of substrates that are not resistant to high temperatures, and can be processed over a large area at low cost.

[0010] To achieve the above objectives, the present invention adopts the following technical solution.

[0011] A low-temperature synthesis method for a long-lasting self-cleaning coating, comprising the following steps:

[0012] (1) Stable aqueous Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0013] 1) Preparation of pure β-Ti(OH)4 precipitate

[0014] (a) Add titanium dioxide powder to concentrated sulfuric acid, place in a water bath, and stir until the titanium dioxide powder is completely dissolved to obtain a titanium dioxide solution.

[0015] (b) Under ice-water bath conditions, the above titanium dioxide solution was added to pure water to obtain a diluted titanium dioxide solution;

[0016] (c) After diluting concentrated ammonia, add it dropwise to the above diluted titanium dioxide solution, control the final pH value to 6-8, and obtain a white β-Ti(OH) precipitate;

[0017] (d) The β-Ti(OH)4 precipitate obtained in the above steps is ultrasonically dispersed with pure water and centrifuged to obtain pure β-Ti(OH)4 precipitate;

[0018] 2) Stable water-based Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0019] (a) Add H2O2 to the pure β-Ti(OH)4 precipitate from the previous step to obtain a clear and transparent orange solution; place a Pt sheet in the solution, place it in a water bath, remove excess H2O2, and obtain a β-Ti(OH)4 solution.

[0020] (b) Under ice-water bath conditions, AgNO3 was added to the above β-Ti(OH)4 solution to obtain stable aqueous Ag. + -(Ti(O2)) 2- Complex precursor solution;

[0021] (2)Ag + -(Ti(O2)) 2- Spraying of complex precursor solution

[0022] 1) The above Ag + -(Ti(O2)) 2- The aqueous solution of the complex precursor was mixed with anhydrous ethanol, sonicated, and the bubbles were removed to obtain a clear alcohol-water mixture solution.

[0023] 2) The above alcohol-water mixture is sprayed onto a substrate that is not resistant to high temperatures to obtain a material with Ag. + -(Ti(O2)) 2- Substrates that are not resistant to high temperatures after solution coating of complex precursors;

[0024] (3) Low temperature curing

[0025] 1) The substrate that has been sprayed and is not resistant to high temperatures is then cured with ultraviolet light to obtain cured Ag. + -(Ti(O2)) 2- Substrates that are not resistant to high temperatures after solution coating of complex precursors;

[0026] 2) Preparation of high-temperature resistant substrates with low-temperature deposited nano-silver-titanium dioxide coating

[0027] The cured Ag prepared in the above steps + -(Ti(O2)) 2- The high-temperature resistant substrate with a complex precursor solution coating is dried at 100°C to complete the coating curing, thereby obtaining a high-temperature resistant substrate with a low-temperature deposited nano-silver-titanium dioxide coating.

[0028] Preferably, the heat-sensitive substrate includes wood, textiles, or paper.

[0029] Preferably, in step (1) of (a), the purity of the titanium dioxide powder is 99.9%; the mass concentration of the concentrated sulfuric acid is 98%; the temperature of the water bath is 80°C; and the reaction is stirred for 30 minutes.

[0030] Preferably, in step (1) of (c), the concentrated ammonia is diluted 10 times and the pH value is 7.

[0031] Preferably, in step (1) of 1) of (d), the centrifugation speed is 2000 rpm to 4000 rpm; repeat the above steps 5 times.

[0032] Preferably, in step (1) 2) (a), the pure β-Ti(OH)4 precipitate is mixed with H2O2 at a molar ratio of 1:4; the water bath temperature is 50°C and the time is 30 min.

[0033] Preferably, in step (1) 2) (b), the ice-water bath condition is 0°C.

[0034] Preferably, in step (1) 2) (b), AgNO3 with a solid content of 99.9% is added at a Ti:Ag molar ratio of 10:1.

[0035] Preferably, in step (2) 1), the mixture is mixed with anhydrous ethanol at a volume ratio of 20% and sonicated for 15 minutes.

[0036] Preferably, in step (2) 2), a 0.5mm diameter spray gun is used at a pressure of 1.5 atmospheres, at a concentration of 100mg / m³. 2 The amount of coating is sprayed onto substrates that are not resistant to high temperatures.

[0037] Preferably, in step (2) 2), the ultraviolet curing uses a wavelength of 254 nm and a surface light intensity of 2 mW / cm². 2 UV lamp treatment for 10 minutes.

[0038] Another objective of this invention is to provide a substrate prepared by a low-temperature synthesis method for a long-lasting self-cleaning coating.

[0039] The above-mentioned objective of this invention is achieved through the following technical solution:

[0040] A substrate prepared by a low-temperature synthesis method for a long-lasting self-disinfecting coating includes a low-temperature deposited nano-silver-titanium dioxide coating, wherein the coating and the substrate are chemically bonded together.

[0041] Preferably, the low-temperature deposited nano-silver-titanium dioxide coating has an Ag-TiO2 heterostructure.

[0042] Another object of the present invention is to provide an Ag + -(Ti(O2)) 2- Preparation of complex precursor solution.

[0043] The above-mentioned objective of this invention is achieved through the following technical solution:

[0044] A type of Ag + -(Ti(O2)) 2- The preparation steps for the complex precursor solution are as follows:

[0045] (1) Preparation of pure β-Ti(OH)4 precipitate

[0046] (a) Add titanium dioxide powder to concentrated sulfuric acid, place in a water bath, and stir until the titanium dioxide powder is completely dissolved to obtain a titanium dioxide solution.

[0047] (b) Under ice-water bath conditions, the above titanium dioxide solution was added to pure water to obtain a diluted titanium dioxide solution;

[0048] (c) After diluting concentrated ammonia, add it dropwise to the above diluted titanium dioxide solution, control the final pH value to 6-8, and obtain a white β-Ti(OH) precipitate;

[0049] (d) The β-Ti(OH)4 precipitate obtained in the above steps is ultrasonically dispersed with pure water and centrifuged to obtain pure β-Ti(OH)4 precipitate;

[0050] (2) Stable water-based Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0051] (a) Add H2O2 to the pure β-Ti(OH)4 precipitate from the previous step to obtain a clear and transparent orange solution; place a Pt sheet in the solution, place it in a water bath, remove excess H2O2, and obtain a β-Ti(OH)4 solution.

[0052] (b) Under ice-water bath conditions, AgNO3 was added to the above β-Ti(OH)4 solution to obtain stable aqueous Ag. + -(Ti(O2)) 2- Complex precursor solution.

[0053] Preferably, the heat-sensitive substrate includes wood, textiles, or paper.

[0054] Preferably, in step (1) (a), the purity of the titanium dioxide powder is 99.9%; the mass concentration of concentrated sulfuric acid is 98%; the temperature of the water bath is 80°C; and the reaction is stirred for 30 minutes.

[0055] Preferably, in step (1) (c), the concentrated ammonia is diluted 10 times and the pH value is 7.

[0056] Preferably, in step (1) of step (d), the centrifugation speed is 2000 rpm to 4000 rpm; the above steps are repeated 5 times.

[0057] Preferably, in step (2) (a), the pure β-Ti(OH)4 precipitate is mixed with H2O2 at a molar ratio of 1:4; the water bath temperature is 50°C and the time is 30 min.

[0058] Preferably, in step (2) (b), the ice-water bath condition is 0°C.

[0059] Preferably, in step (2) (b), AgNO3 with a solid content of 99.9% is added according to the molar ratio of Ti:Ag of 10:1.

[0060] Beneficial effects:

[0061] This invention overcomes the limitation that traditional high-temperature thermally deposited titanium dioxide nano-coating technology cannot be applied to substrate materials that are not resistant to high temperatures. It achieves low-temperature deposition of visible light-absorbing nano-silver-titanium dioxide coatings on the surface of substrate materials that are not resistant to high temperatures. This low-temperature deposited nano-silver-titanium dioxide coating has a self-disinfection function that can achieve long-lasting antibacterial and harmful gas purification on the substrate surface.

[0062] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this does not imply any limitation on the scope of protection of the present invention. Attached Figure Description

[0063] Figure 1 This is a transmission electron microscope (TEM) image of the Ag-TiO2 heterostructure nanostructure in the nano-spraying liquid obtained in step 2 of Example 1 of the present invention.

[0064] Figure 2 The nonwoven fabric obtained in step 3 (1) of Example 1 of this invention is photocured and loaded with Ag-TiO2 nanoparticles on the surface of the nonwoven fabric fiber. The nonwoven fabric is cut into 1cm*1cm samples, glued to the electron microscope sample stage with conductive adhesive, and then sputtered with gold. The morphology is observed by a Japanese scanning electron microscope (4800) under the conditions of 10KV high voltage and 10uA current.

[0065] Figure 3 After the Ag-TiO2 nanoparticles on the surface of the nonwoven fabric fiber obtained in step 3 (2) of Example 1 of the present invention were thermally cured and loaded, the nonwoven fabric was cut into 1cm*1cm samples, glued to the electron microscope sample stage with conductive adhesive, and after gold sputtering treatment, the morphology was observed with a Japanese scanning electron microscope (4800) under the conditions of 10KV high voltage and 10uA current. Ag-TiO2 nanoparticles showed agglomeration deposition results.

[0066] Figure 4-1 The results are from the antibacterial test on the surface of the untreated nonwoven fibers.

[0067] Figure 4-2 The results are from bacterial culture using PBS.

[0068] Figure 4-3 The result is the sample after photocuring and loading of Ag-TiO2 nanoparticles on the surface of nonwoven fiber obtained in step 3 (1) of Example 1 of the present invention.

[0069] Figure 4-4 Results of culturing with PBS. Detailed Implementation

[0070] Unless otherwise specified, in the following embodiments, the raw materials and methods are all commercially available and conventional in the art; all units are weight units.

[0071] Example 1 (Non-woven fabric)

[0072] A low-temperature synthesis method for a long-lasting self-disinfecting coating (a method for preparing a substrate that is not resistant to high-temperature treatment with a low-temperature deposited nano-silver-titanium dioxide coating), the steps of which are as follows:

[0073] (1) Stable aqueous Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0074] 1) Preparation of pure β-Ti(OH)4 precipitate

[0075] (a) Add 10g of 99.9% pure titanium dioxide powder to 10ml of 98% concentrated sulfuric acid, and stir in an 80℃ water bath for 30min until the titanium dioxide powder is completely dissolved to obtain a titanium dioxide solution.

[0076] (b) Under ice-water bath conditions, the above titanium dioxide solution was added to 100 ml of pure water to obtain a diluted titanium dioxide solution;

[0077] (c) Dilute concentrated ammonia water 10 times and add it dropwise to the above diluted titanium dioxide solution, control the endpoint pH value to 7, and obtain a white β-Ti(OH) precipitate;

[0078] (d) Disperse the β-Ti(OH)4 precipitate obtained in the above steps with 10 ml of pure water by ultrasonication, centrifuge at 3000 rpm to settle, and remove the supernatant to obtain the precipitate.

[0079] (f) Repeat step (d) 5 times to obtain pure β-Ti(OH)4 precipitate (Ti(OH)4 has two configurations, α and β, only β-Ti(OH)4 can be completely dissolved in acid, and β-Ti(OH)4 can only be prepared by using NH4H2O as a weak base in a strong acid environment).

[0080] 2) Stable water-based Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0081] (a) Add H2O2 to the pure β-Ti(OH)4 precipitate from the previous step at a molar ratio of 1:4 to obtain a clear orange solution; place a Pt sheet in the solution and heat in a 50°C water bath for 30 min to remove excess H2O2 and obtain a β-Ti(OH)4 solution.

[0082] (b) Under 0°C ice-water bath conditions, in the above β-Ti(OH)4 solution, AgNO3 with a solid content of 99.9% was added at a Ti:Ag molar ratio of 10:1 to obtain stable aqueous Ag. + -(Ti(O2)) 2- The precursor solution of the complex (Ag can promote the decomposition of H2O2 and simultaneously form nano-Ag precipitate, so Pt must first be used to decompose the free peroxide ions that are not coordinated with Ti, and then AgNO3 is added to obtain stable Ag) + -(Ti(O2)) 2- (Compound precursor solution);

[0083] (2)Ag + -(Ti(O2)) 2- Spraying of complex precursor solution

[0084] 1) The above Ag + -(Ti(O2)) 2- The aqueous solution of the complex precursor was mixed with anhydrous ethanol at a volume ratio of 20%, and sonicated for 15 minutes to remove air bubbles, resulting in a clear alcohol-water mixture solution (to solve the wettability problem of hydrophilic coating processing on hydrophobic substrate surfaces).

[0085] 2) Apply the above alcohol-water mixture to a 0.5mm nozzle using a spray gun at a pressure of 1.5 atmospheres, at a concentration of 100 mg / m³. 2 The coating amount is sprayed onto the nonwoven fabric; to obtain Ag... + -(Ti(O2)) 2- Nonwoven fabrics coated with complex precursor solution;

[0086] (3) Low temperature curing

[0087] 1) The nonwoven fabric after the above spraying is subjected to a light test at a wavelength of 254nm and a surface light intensity of 2mW / cm². 2 The Ag was cured by treating it with a UV lamp for 10 minutes. + -(Ti(O2)) 2- Nonwoven fabric with a solution coating of a complex precursor (using photocuring to prevent heterogeneous nucleation of the nano-coating);

[0088] 2) Preparation of nonwoven fabric with low-temperature deposited nano-silver-titanium dioxide coating

[0089] The cured Ag prepared in the above steps + -(Ti(O2)) 2- The nonwoven fabric coated with the complex precursor solution was dried at 100°C to complete the coating curing, thus obtaining a nonwoven fabric with a low-temperature deposited nano-silver-titanium dioxide coating.

[0090] Product performance testing:

[0091] like Figure 1 The image shown is a transmission electron microscope (TEM) image of the Ag-TiO2 heterostructure nanostructure in the nano-spraying liquid obtained in step 2 of Example 1 of this invention. A portion of the sample was dispersed in an ethanol solution and sonicated. Then, several drops of the dispersed liquid were added dropwise to a copper grid. After drying, TEM images were taken using a JEOL JEM-F200 microscope (Japan) with an accelerating voltage of 200 kV. Figure 1 The left-hand image shows the overall result of the obtained Ag-TiO2 heterojunction nanostructure magnified 100,000 times, confirming that this step can obtain monodisperse nanoparticles. The right-hand image shows the local result of the obtained Ag-TiO2 heterojunction nanostructure magnified 300,000 times. TEM results confirm that the heterojunction is the (101) crystal plane of anatase TiO2 and the (111) crystal plane of nano-Ag.

[0092] like Figure 2 The image shown is a photograph obtained by photocuring Ag-TiO2 nanoparticles on the surface of the nonwoven fabric fiber obtained in step 3 (1) of Example 1 of the present invention, cutting the nonwoven fabric into 1cm*1cm sample pieces, attaching them to the electron microscope sample stage with conductive adhesive, sputtering gold, and observing the morphology with a Japanese scanning electron microscope (4800) under the conditions of 10KV high voltage and 10uA current. Figure 2 In the image, the left image shows the result magnified 1100 times, confirming that nanoparticles are loaded onto the nonwoven fabric fibers; the right image shows the result of loading nanoparticles onto a single fiber after magnification 5000 times, confirming that the nanoparticles were successfully loaded onto the nonwoven fabric fibers.

[0093] like Figure 3 As shown, after the Ag-TiO2 nanoparticles on the surface of the nonwoven fabric fiber obtained in step 3 (2) of Example 1 of the present invention were thermally cured and loaded, the nonwoven fabric was cut into 1cm*1cm samples, glued to the electron microscope sample stage with conductive adhesive, and after gold sputtering treatment, the morphology was observed with a Japanese scanning electron microscope (4800) under the conditions of 10KV high voltage and 10uA current. Ag-TiO2 nanoparticles showed agglomeration deposition results.

[0094] like Figures 4-1 to 4-4As shown, the nonwoven fabric fibers obtained in step 3 (1) of Example 1 of this invention, after being photocured and loaded with Ag-TiO2 nanoparticles, and the original nonwoven fabric without antibacterial coating, were cut to 4cm*5cm size and placed into 250mL Erlenmeyer flasks. 70mL of PBS buffer was added, and the flasks were sealed with rubber stoppers and placed in an ultrasonic cleaner. After ultrasonication for 20 minutes, the flasks were removed and sterilized in a high-temperature and high-pressure autoclave at 121℃. After sterilization, the flasks were taken out for later use. 5.0mL of freshly prepared bacterial suspension was added to the sterilized Erlenmeyer flasks containing the samples, so that the concentration of the bacterial suspension in PBS was 1.0×10⁻⁶. 4 CFU / mL ~5.0X10 4 CFU / mL, fix the conical flask on a shaking table, shake at 300 rpm for 2 min at 20℃~25℃, and take 1 ml as the pre-shaking sample solution of the experimental group; continue shaking for 1 h, and take 1 mL of the sample solution as the post-shaking sample solution of the experimental group. Dilute the pre-shaking and post-shaking sample solutions appropriately with PBS, and take 1 mL of each, put them into a Petri dish, and inoculate them into a solid culture medium Petri dish by spread method. Incubate at 37℃ for 24 h, and count the colonies. At the same time, set up a control sample group, a no-sample group, and a PSB calibration group. The control sample is of the same material and size as the experimental sample but does not contain antibacterial components. After sterilization, the control sample is tested in the same way as the experimental sample group. For the no-sample group, take 5 ml of bacterial suspension and 70 ml of PBS and add them to a 250 ml Erlenmeyer flask, mix well, and take 1 ml of the sample solution before shaking for 2 min and 1 ml of the sample solution after shaking for 1 h, and incubate by spread method. For the PBS calibration group, take 75 ml of the sample solution before shaking for 2 min and 1 mL of the sample solution after shaking for 1 h. Add PBS to a 250ml flask, and perform spread culture on 1ml of sample solution before shaking for 2 minutes and after shaking for 1 hour, respectively, to observe whether bacteria grow and determine the effectiveness of PBS;

[0095] like Figure 4-1 As shown, this is the result of the antibacterial test on the surface of the original, untreated nonwoven fabric fibers. The left figure shows the bacterial culture result after 2 minutes, and the right figure shows the bacterial culture result after 1 hour. There was no significant change in the number of colonies, which confirms that the untreated nonwoven fabric has no inhibitory effect on bacterial growth.

[0096] like Figure 4-2 The image shows the results of the bacteria cultured in PBS. The left image shows the bacterial culture results after 2 minutes, and the right image shows the bacterial culture results after 1 hour, confirming that the bacteria used were qualified bacterial samples under the experimental conditions.

[0097] like Figure 4-3As shown, this is the result of the sample after photocuring and loading of Ag-TiO2 nanoparticles on the surface of nonwoven fabric fibers obtained in step 3 (1) of Example 1 of the present invention. The left figure is the result of bacterial culture after 2 min, and the right figure is the result of bacterial culture after 1 h. The number of colonies is significantly reduced, which confirms that the nonwoven fabric treated with Ag-TiO2 coating has a significant inhibitory effect on bacterial growth.

[0098] like Figure 4-4 The results of the PBS culture are shown below. The left image shows the bacterial culture results after 2 minutes, and the right image shows the bacterial culture results after 1 hour. No bacterial growth was observed, confirming that the PBS system used was not contaminated.

[0099] Example 2 (Solid Wood Panels)

[0100] A low-temperature synthesis method for a long-lasting self-cleaning coating, comprising the following steps:

[0101] (1) Stable aqueous Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0102] 1) Preparation of pure β-Ti(OH)4 precipitate

[0103] (a) Add 10g of 99.9% pure titanium dioxide powder to 10ml of 98% concentrated sulfuric acid, and stir in an 80℃ water bath for 30min until the titanium dioxide powder is completely dissolved to obtain a titanium dioxide solution.

[0104] (b) Under ice-water bath conditions, the above titanium dioxide solution was added to 100 ml of pure water to obtain a diluted titanium dioxide solution;

[0105] (c) Dilute concentrated ammonia water 10 times and add it dropwise to the above diluted titanium dioxide solution, control the endpoint pH value to 7, and obtain a white β-Ti(OH) precipitate;

[0106] (d) Disperse the β-Ti(OH)4 precipitate obtained in the above steps with 10 ml of pure water by ultrasonication, centrifuge at 3000 rpm to settle, and repeat the above steps 5 times to obtain pure β-Ti(OH)4 precipitate (Ti(OH)4 has two configurations, α and β, only β-Ti(OH)4 can be completely dissolved in acid, and β-Ti(OH)4 can only be prepared by using NH4H2O as a weak base in a strong acid environment).

[0107] 2) Stable water-based Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0108] (a) Add H2O2 to the pure β-Ti(OH)4 precipitate from the previous step at a molar ratio of 1:4 to obtain a clear orange solution; place a Pt sheet in the solution and heat in a 50°C water bath for 30 min to remove excess H2O2 and obtain a β-Ti(OH)4 solution.

[0109] (b) Under 0°C ice-water bath conditions, in the above β-Ti(OH)4 solution, AgNO3 with a solid content of 99.9% was added at a Ti:Ag molar ratio of 10:1 to obtain stable aqueous Ag. + -(Ti(O2)) 2- The precursor solution of the complex (Ag can promote the decomposition of H2O2 and simultaneously form nano-Ag precipitate, so Pt must first be used to decompose the free peroxide ions that are not coordinated with Ti, and then AgNO3 is added to obtain stable Ag) + -(Ti(O2)) 2- (Compound precursor solution);

[0110] (2)Ag + -(Ti(O2)) 2- Spraying of complex precursor solution

[0111] 1) The above Ag + -(Ti(O2)) 2- The aqueous solution of the complex precursor was mixed with anhydrous ethanol at a volume ratio of 20%, and sonicated for 15 minutes to remove air bubbles, resulting in a clear alcohol-water mixture solution (to solve the wettability problem of hydrophilic coating processing on hydrophobic substrate surfaces).

[0112] 2) Apply the above alcohol-water mixture to a 0.5mm nozzle using a spray gun at a pressure of 1.5 atmospheres, at a concentration of 100 mg / m³. 2 The amount of coating applied is sprayed onto solid wood panels to obtain Ag-coated substrates. + -(Ti(O2)) 2- Solid wood boards coated with a complex precursor solution;

[0113] (3) Low temperature curing

[0114] 1) The above-mentioned sprayed solid wood board is then subjected to a light test using a wavelength of 254nm and a surface gloss intensity of 2mW / cm². 2 The Ag was cured by treating it with a UV lamp for 10 minutes. + -(Ti(O2)) 2- Solid wood boards coated with a complex precursor solution (using photocuring to prevent heterogeneous nucleation of the nano-coating);

[0115] 2) Preparation of solid wood boards with low-temperature deposited nano-silver-titanium dioxide coating

[0116] The cured Ag prepared in the above steps + -(Ti(O2)) 2- Solid wood boards coated with a complex precursor solution are dried at 100°C to complete the coating curing, resulting in solid wood boards with a low-temperature deposited nano-silver-titanium dioxide coating.

[0117] Example 3

[0118] A low-temperature synthesis method for a long-lasting self-cleaning coating, comprising the following steps:

[0119] (1) Stable aqueous Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0120] 1) Preparation of pure β-Ti(OH)4 precipitate

[0121] (a) Add 10g of 99.9% pure titanium dioxide powder to 10ml of 98% concentrated sulfuric acid, and stir in an 80℃ water bath for 30min until the titanium dioxide powder is completely dissolved to obtain a titanium dioxide solution.

[0122] (b) Under ice-water bath conditions, the above titanium dioxide solution was added to 100 ml of pure water to obtain a diluted titanium dioxide solution;

[0123] (c) Dilute concentrated ammonia water 10 times and add it dropwise to the above diluted titanium dioxide solution, control the endpoint pH value to 7, and obtain a white β-Ti(OH) precipitate;

[0124] (d) Disperse the β-Ti(OH)4 precipitate obtained in the above steps with 10 ml of pure water by ultrasonication, centrifuge at 3000 rpm to settle, and repeat the above steps 5 times to obtain pure β-Ti(OH)4 precipitate (Ti(OH)4 has two configurations, α and β, only β-Ti(OH)4 can be completely dissolved in acid, and β-Ti(OH)4 can only be prepared by using NH4H2O as a weak base in a strong acid environment).

[0125] 2) Stable water-based Ag + -(Ti(O2)) 2- Preparation of complex precursor solution

[0126] (a) Add H2O2 to the pure β-Ti(OH)4 precipitate from the previous step at a molar ratio of 1:4 to obtain a clear orange solution; place a Pt sheet in the solution and heat in a 50°C water bath for 30 min to remove excess H2O2 and obtain a β-Ti(OH)4 solution.

[0127] (b) Under 0°C ice-water bath conditions, in the above β-Ti(OH)4 solution, AgNO3 with a solid content of 99.9% was added at a Ti:Ag molar ratio of 10:1 to obtain stable aqueous Ag. + -(Ti(O2)) 2- The precursor solution of the complex (Ag can promote the decomposition of H2O2 and simultaneously form nano-Ag precipitate, so Pt must first be used to decompose the free peroxide ions that are not coordinated with Ti, and then AgNO3 is added to obtain stable Ag) + -(Ti(O2)) 2- (Compound precursor solution);

[0128] (2)Ag + -(Ti(O2)) 2- Spraying of complex precursor solution

[0129] 1) The above Ag + -(Ti(O2)) 2- The aqueous solution of the complex precursor was mixed with anhydrous ethanol at a volume ratio of 20%, and sonicated for 15 minutes to remove air bubbles, resulting in a clear alcohol-water mixture solution (to solve the wettability problem of hydrophilic coating processing on hydrophobic substrate surfaces).

[0130] 2) Apply the above alcohol-water mixture to a 0.5mm nozzle using a spray gun at a pressure of 1.5 atmospheres, at a concentration of 100 mg / m³. 2 The coating amount is sprayed onto the corrugated paper; to obtain Ag... + -(Ti(O2)) 2- Corrugated paper with a solution coating of a complex precursor;

[0131] (3) Low temperature curing

[0132] 1) The above-sprayed corrugated paper is then subjected to a light test with a wavelength of 254nm and a surface gloss intensity of 2mW / cm². 2 The Ag was cured by treating it with a UV lamp for 10 minutes. + -(Ti(O2)) 2- Corrugated paper with a solution coating of a complex precursor (using photocuring to prevent heterogeneous nucleation of the nano-coating);

[0133] 2) Preparation of corrugated paper with low-temperature deposited nano-silver-titanium dioxide coating

[0134] The cured Ag prepared in the above steps + -(Ti(O2)) 2- The corrugated paper coated with the complex precursor solution was dried at 100°C to complete the coating curing, resulting in corrugated paper with a low-temperature deposited nano-silver-titanium dioxide coating. The innovative points of this invention are: 1. Stable aqueous Ag... +-(Ti(O2)) 2- The complex precursor solution can achieve the formation of a heterostructure of Ag-TiO2, thereby utilizing the plasma effect of Ag to absorb and form a direct and effective electron transfer system between Ag and TiO2 in the visible light region; 2. The photocuring process can utilize the free radical process generated by photoexcitation at low temperature to form chemical bonds between the inorganic coating and the organic substrate molecules, thereby achieving direct low-temperature curing and deposition of crystalline nano-coatings without the need for traditional high-temperature sintering.

[0135] This invention manufactures a long-lasting and highly safe photocatalytic self-disinfecting coating on organic substrates with low thermal resistance, such as wood, textiles, and paper, at low temperatures.

[0136] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for low-temperature synthesis of long-acting self-decomposing and self-sterilizing coating, comprising the following steps: (1) Stable aqueous Ag + - (Ti (02)) 2- Preparation of complex precursor solution 1) Preparation of pure β-Ti(OH)4 precipitate (a) adding titanium dioxide powder into concentrated sulfuric acid, water bath, stirring until the titanium dioxide powder is completely dissolved to obtain a titanium dioxide solution; (b) adding the titanium dioxide solution into pure water under ice water bath condition to obtain a diluted titanium dioxide solution; (c) adding diluted concentrated ammonia water into the diluted titanium dioxide solution drop by drop under control of the final pH value of 6-8 to obtain white β-Ti(OH)4 precipitate; (d) ultrasonic dispersion of the white β-Ti(OH)4 precipitate obtained in the above step with pure water, centrifugal sedimentation to obtain pure β-Ti(OH)4 precipitate; 2) Stable aqueous Ag + - (Ti (02)) 2- Preparation of complex precursor solution (a) adding the pure β-Ti(OH)4 precipitate in the above step into H2O2 to obtain an orange clear transparent solution, placing a Pt sheet, water bath, removing excess H2O2 to obtain a β-Ti(OH)4 solution; (b) under ice water bath condition, AgNO3 was added into the above β-Ti(OH)4 solution to obtain stable aqueous Ag + - (Ti (O2)) 2- complex precursor solution; (2) Ag + - (Ti (02)) 2- Spraying of the complex precursor solution 1) AgNO3 solution was prepared by dissolving 0.5 g of AgNO3 in 50 mL of deionized water. + - (Ti (O2)) 2- The complex precursor aqueous solution was mixed with anhydrous ethanol, ultrasonicated, and bubbles were removed to obtain a clear alcohol-water mixed solution. 2) The above alcohol-water mixed solution is sprayed on a high-temperature-resistant treatment substrate to obtain a Ag + - (Ti (O2)) 2- high-temperature-resistant treatment substrate coated with a complex precursor solution (3) Low-temperature solidification 1) The above high temperature non-resistant treated substrate after spraying, ultraviolet curing, obtain the cured Ag + - (Ti (02)) 2- High temperature non-resistant treated substrate of complex precursor solution coating; 2) Preparation of high-temperature treatment-resistant substrate with low-temperature deposited nano-silver-titanium dioxide coating The cured Ag + - (Ti (02)) 2- The high-temperature non-resistant treated substrate coated with the complex precursor solution is dried at 100°C to complete the curing of the coating, and a high-temperature non-resistant treated substrate with a low-temperature deposited nano-silver-titanium dioxide coating is obtained.

2. The method of claim 1, wherein the long-acting self-immolative coating is synthesized at a low temperature. The high-temperature treatment-resistant substrate comprises wood material, textile or paper.

3. The method of claim 2, wherein the long-acting self-immolative coating is synthesized at a low temperature. In step (1) 1) (a), the purity of the titanium dioxide powder is 99.9%, the mass concentration of the concentrated sulfuric acid is 98%, the water bath temperature is 80°C, and the stirring reaction time is 30 min; in step (1) 1) (c), the concentrated ammonia water is diluted by 10 times, and the pH value is 7; in step (1) 1) (d), the centrifugal speed is 2000 rpm-4000 rpm, and the above steps are repeated for 5 times.

4. The method of claim 3, wherein the long-acting self-immolative coating is synthesized at a low temperature. In step (1) 2) (a), the pure β-Ti(OH)4 precipitate is mixed with H2O2 at a molar ratio of 1:4, the water bath temperature is 50°C, and the time is 30 min; in step (1) 2) (b), the ice water bath condition is 0°C; in step (1) 2) (b), AgNO3 with a solid content of 99.9% is added at a Ti:Ag molar ratio of 10:

1.

5. The method of claim 4, wherein the long-acting self-immolative coating is synthesized at a low temperature. In step (2) 1), mixed with absolute ethanol at a volume ratio of 20%, and ultrasonic for 15 min; in step (2) 2), sprayed on the high-temperature-resistant disposal substrate at a spraying amount of 100 mg / m 2 with a 0.5 mm caliber spray gun at a pressure of 1.5 atmospheres; in step (2) 2), the ultraviolet curing was treated with an ultraviolet lamp with a wavelength of 254 nm and a surface light intensity of 2 mW / cm 2 for 10 min.

6. The substrate prepared by the method for low-temperature synthesis of long-acting self-decomposing and self-sterilizing coating according to any one of claims 1-5, comprising a low-temperature deposited nano-silver-titanium dioxide coating, and a chemical bond formed between the coating and the substrate.

7. The substrate prepared according to the process for low temperature synthesis of long- lasting self-cleaning coatings according to claim 6, characterized by: The low-temperature deposited nano-silver-titanium dioxide coating has an Ag-TiO2 heterostructure.

8. An Ag + - (Ti (02)) 2- A method for preparing a complex precursor solution, the steps of which are as follows: (1) Preparation of pure β-Ti(OH)4 precipitate (a) adding titanium dioxide powder into concentrated sulfuric acid, water bath, stirring until the titanium dioxide powder is completely dissolved to obtain a titanium dioxide solution; (b) adding the titanium dioxide solution into pure water under ice water bath condition to obtain a diluted titanium dioxide solution; (c) adding diluted concentrated ammonia water into the diluted titanium dioxide solution drop by drop under control of the final pH value of 6-8 to obtain white β-Ti(OH)4 precipitate; (d) ultrasonic dispersion of the white β-Ti(OH)4 precipitate obtained in the above step with pure water, centrifugal sedimentation to obtain pure β-Ti(OH)4 precipitate; (2) Stable aqueous Ag + - (Ti (02)) 2- Preparation of complex precursor solution (a) The pure β-Ti(OH)4 precipitate in the previous step is added with H2O2 to obtain an orange clear transparent solution; Pt sheet is put in and water bath is used to remove the excess H2O2 to obtain a β-Ti(OH)4 solution; (b) under ice water bath condition, AgNO3 was added into the above β-Ti(OH)4 solution to obtain stable aqueous Ag + - (Ti (O2)) 2- complex precursor solution.

9. The Ag of claim 8 + - (Ti (02)) 2- The method for preparing a complex precursor solution is characterized by comprising the steps of: In step (1) (a), the purity of the titanium dioxide powder is 99.9%; the mass concentration of concentrated sulfuric acid is 98%; the temperature of the water bath is 80°C, and the stirring reaction is performed for 30 min; in step (1) (c), the concentrated ammonia water is diluted by 10 times; the pH value is 7; in step (1) (d), the centrifugal speed is 2000 rpm-4000 rpm; and the above steps are repeated for 5 times.

10. The Ag of claim 9 + - (Ti (02)) 2- The method for preparing a complex precursor solution is characterized by comprising the steps of: In step (2) (a), the pure β-Ti(OH)4 precipitate is mixed with H2O2 at a molar ratio of 1:4; the water bath temperature is 50°C, and the time is 30 min; in step (2) (b), the ice water bath condition is 0°C; in step (2) (b), the molar ratio of Ti:Ag is 10:1, and AgNO3 with a solid content of 99.9% is added.

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