A hybrid silica sol photocatalytic antibacterial coating and its preparation method

Abstract

This invention relates to a hybrid silica sol photocatalytic antibacterial coating and its preparation method, belonging to the field of photocatalytic antibacterial technology. The photocatalytic antibacterial coating uses a thiophene-based polymer as the active component and an inorganic hybrid sol as the carrier. The thiophene-based polymer is PD-(COOH)2 or PD-COOH, without a fixed morphology; the carrier is an inorganic hybrid silica sol or an inorganic hybrid silicon-titanium sol. The preparation method includes steps such as preparing the polymer, preparing the hybrid sol, and using a thermal polymerization method to form bonds between the polymer and the hybrid silica sol to prepare the antibacterial sol coating. The polythiophene hybrid silica sol photocatalytic antibacterial coating of this invention has high biocompatibility, wide application fields, and a simple film-forming process, convenient synthesis, high efficiency, and stability.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic antibacterial technology, and specifically relates to an organic-inorganic hybrid silica sol photocatalytic antibacterial coating with thiophene-based polymer as the photocatalytic antibacterial component and its preparation method. Background Technology

[0002] Bacterial infection has always been a major challenge threatening human survival. In recent years, the spread of pathogenic microorganisms in the environment has led to frequent influenza outbreaks, which have dealt a heavy blow to human health and the socio-economic situation. Therefore, the prevention and control of the spread and infection of pathogenic microorganisms has become a major public health problem that the world is facing and urgently needs to solve. Antibiotics are a widely used and effective antibacterial strategy, but with the abuse of antibiotics, the problem of bacterial resistance has become increasingly serious, increasing the susceptibility of humans and animals to drug-resistant pathogens. Photocatalytic antibacterial has the advantages of high efficiency in killing bacteria, no drug resistance and no side effects, and has become an important antibacterial strategy. (Ziling Z, Bo L, Xiangmei L, et al. Recent Progress in Photocatalytic Antibacterial[J].ACS APPLIED BIO MATERIALS,2021,4(5):3909-3936.) In the photocatalytic process, the photocatalytic material is excited by light of different wavelengths to produce reactive oxygen species (ROS) or other substances, which are used to kill various pathogenic microorganisms, such as bacteria, viruses, fungi, parasites and algae. (Bei R, Lei R, Zuokai W, et al. Photocatalytic Antimicrobials: Principles, Design Strategies, and Applications. [J]. Chemical Reviews, 2023.) Compared with traditional antimicrobial materials and technologies, which have disadvantages such as easy aggregation, instability, easy failure, toxic by-products, and high cost, photocatalytic technology has advantages such as low energy consumption, simple operation, stability, and green environmental protection, and has broad application prospects, playing an irreplaceable role in the field of antimicrobial.

[0003] Currently, antibacterial materials are mainly classified into inorganic antibacterial materials, organic antibacterial materials, natural antibacterial materials, and composite antibacterial materials. Among them, organic antibacterial materials are characterized by their rich variety, wide range of applications, significant antibacterial effects, high biosafety, and relatively mature application technology, and they dominate the antibacterial product series. (Bei R, Zuokai W, Wenlin C, et al. Organic Photo-antimicrobials: Principles, Molecule Design, and Applications.[J]. Journal of the American Chemical Society, 2021, 143(43)) Polythiophene and its derivatives, which have a wide spectral response, easily tunable energy level structure, high carrier mobility, and high stability, can absorb visible and near-infrared light to achieve antibacterial effects, and therefore have attracted much attention in photocatalytic applications. Currently, the reported polythiophene derivative antibacterial materials are mainly powder materials, while research on antibacterial coatings is very limited. Surface coatings or modifications can maintain the overall performance of the material while only changing the surface properties, and have been considered a promising strategy for introducing antibacterial effects into biomedical devices. (Zhao C, Zhou L, Chiao M, et al. Antibacterial hydrogel coating: Strategies in surface chemistry[J]. Advances in Colloid and Interface Science, 2020, 285(10): 2280-102280.) Compared with powder coatings, liquid antibacterial coatings have significant advantages in forming stable antibacterial coatings on object surfaces, adaptability to various matrix materials, mechanical properties, and material recyclability. Hybrid silica sol overcomes the shortcomings of poor adhesion and moldability of existing antibacterial coatings, and has excellent flexibility and hardness.

[0004] Chinese patent CN107603412A discloses a method for preparing an antibacterial coating by covalently bonding carboxylated magnolol and cordycepin to an epoxy resin matrix. The coating material exhibits improved chemical stability and heat resistance; the antibacterial macromolecules are well dispersed and do not migrate within the matrix, thus maintaining their bactericidal ability for a longer period and extending the coating's service life; it is safe to use and has no toxic side effects. Chinese patent CN104830135B discloses a method for preparing an antibacterial coating from polyacrylonitrile, dopamine, an antibacterial adhesive, and a bactericide. This antibacterial coating utilizes the adhesive properties of the catechol units in dopamine, resulting in high adhesion and good adhesion stability. It is suitable for medical devices with various surface properties and complex shapes, demonstrating strong versatility and practicality. Chinese patent CN113045922A discloses a method for preparing an antibacterial coating by embedding an inorganic antibacterial agent composed of nano-silver particles, nano-zinc oxide, nano-copper, and nano-titanium dioxide into a network structure of a silica sol matrix. The resulting antibacterial coating has the advantages of low-temperature rapid curing, transparency, and good antibacterial properties. Chinese patent CN108276820B discloses the preparation of an antibacterial coating of a plant polyphenol-quaternary ammonium salt complex formed by the electrostatic interaction of negatively charged plant polyphenols and positively charged quaternary ammonium salts. In this invention, plant polyphenols and an aqueous solution of quaternary ammonium salts rapidly combine through electrostatic interaction to form a plant polyphenol-quaternary ammonium salt complex, which is a water-insoluble precipitate. This antibacterial coating preparation method is simple and has a short reaction time. Chinese patent CN113698816B discloses a method for preparing an antibacterial coating and its application using chitosan, tannic acid, zinc nanoparticles, copper nanoparticles, a thickener, and an organic solvent. The antibacterial coating exhibits good antibacterial properties and high stability, providing long-lasting antibacterial protection.

[0005] However, overall, there are still some problems with the application and safety of composite antibacterial polymer photocatalysts in current patents and literature. They are poor in terms of light utilization, and some antibacterial coatings contain inorganic metal elements that are difficult to metabolize. The adhesion and hardness of the antibacterial coatings are also weak, which restricts the practical application of photocatalyst coatings. Summary of the Invention

[0006] The technical problem this invention aims to solve is to provide a method for preparing a thiophene-based polymer hybrid silica sol for photocatalytic antibacterial applications, addressing the problems existing in the prior art. The preparation process is simple and inexpensive, and the resulting antibacterial sol exhibits stable properties, excellent adhesion and hardness, and can be applied to photocatalytic antibacterial applications in multiple fields and situations.

[0007] The specific technical solution of the present invention is as follows:

[0008] A hybrid silica sol photocatalytic antibacterial coating uses a thiophene-based polymer as the active component and an inorganic hybrid sol as the carrier. The thiophene-based polymer is PD-(COOH)2 or PD-COOH and has no fixed morphology. The carrier is an inorganic hybrid silica sol or an inorganic hybrid silicon-titanium sol, with a mass ratio of thiophene-based polymer:inorganic hybrid sol = 3 to 5:7.

[0009] Preferably, the thiophene-based polymer is PD-COOH; and the inorganic hybrid sol is an inorganic hybrid silica sol.

[0010] A method for preparing a hybrid silica sol photocatalytic antibacterial coating includes the following steps:

[0011] 1) Preparation of polymer: Using Tin reagent, carboxythiophene dibromide, catalyst, deoxygenated anhydrous toluene and dehydrated and deoxygenated DMF in a mass ratio of 4:3:1:51:20 as raw materials, the mixture was added to a two-necked flask under N2 protection. The temperature was controlled at 100-120℃, the reaction time was controlled at 48-72h, and the stirring speed was 800r / min. After the reaction was completed, the reaction solution was cooled to room temperature and transferred to a round-bottom flask for rotary evaporation. After precipitation with ethanol, the mixture was filtered, and then purified by extraction with ethanol and acetone. Finally, the mixture was dried to obtain the thiophene-based polymer.

[0012] Wherein, the Tin reagent is 5,5'-bis(trimethyltinyl)-2,2'-bithiophene, the catalyst is tetrakis(triphenylphosphine)palladium, and the dibromocarboxythiophene is 2,5-dibromo-3-carboxythiophene or 2,5-dibromo-3,4-dicarboxythiophene. When the dibromocarboxythiophene is 2,5-dibromo-3-carboxythiophene, the resulting thiophene-based polymer is PD-COOH. When the dibromocarboxythiophene is 2,5-dibromo-3,4-dicarboxythiophene, the resulting thiophene-based polymer is PD-(COOH)2.

[0013] 2) Preparation of hybrid sol: Using PVA (polyvinyl alcohol), TEOS (tetrabutyl orthosilicate) and / or TBOT (tetrabutyl titanate) in a mass ratio of 10:4:3, and a capping agent as raw materials, the sol is prepared by hydrolysis and thermal polymerization. First, a PVA aqueous solution with a concentration of 1wt% to 8wt% is prepared. Then, ethanol, deionized water, and 12mol / L concentrated hydrochloric acid are mixed in a mass ratio of 360:18:5, and TEOS and / or TBOT are added. The mass ratio of the mixed solvent to TEOS and / or TBOT is 5:1. The mixture is stirred at room temperature for 3-5 hours to obtain an inorganic sol. The PVA aqueous solution and the inorganic sol are mixed and stirred in a 3:1 ratio. The mixture is heated to 80℃, and then the capping agent is added. The mass ratio of the capping agent to PVA is 1-10:25. The mixture is stirred for another 4-5 hours to obtain the inorganic hybrid sol.

[0014] Wherein, the PVA is PVA-1788, and the end-capping agent is one or a mixture of two of NMA (N-hydroxymethylacrylamide) and MBA (N,N'-methylenebisacrylamide);

[0015] 3) The antibacterial sol coating is prepared by forming bonds between the polymer and the hybrid silica sol using a thermal polymerization method: the o-dichlorobenzene solution of the thiophene-based polymer is added to the inorganic hybrid sol and stirred at 60°C for 9-12 hours. The sol is then coated on a glass plate and dried at 100°C for 3-4 hours to obtain the hybrid silica sol photocatalytic antibacterial coating.

[0016] Preferably, the dibromocarboxythiophene in step 1) is 2,5-dibromo-3-carboxythiophene, and the end-capping agent in step 2) is N-hydroxymethylacrylamide.

[0017] Beneficial effects:

[0018] The polythiophene hybrid silica sol photocatalytic antibacterial coating of this invention exhibits high biocompatibility, wide application range, and a simple film-forming process, convenient synthesis, high efficiency, and stability. The significant technological advancements of this thiophene-based polymer photocatalytic antibacterial agent are reflected in its strong antibacterial effect, high light utilization rate, high safety, excellent hardness, environmental friendliness, and reusability. In particular, the antibacterial effect, light utilization rate, and safety and environmental friendliness are most prominent in photocatalytic antibacterial agents using inorganic hybrid silica sol as a carrier. These results are superior to previously disclosed chitosan coatings or other carrier-composite thiophene-based polymer photocatalytic antibacterial coatings. The resulting sol has a hardness equivalent to five pencils, thus allowing for spin coating, dip coating, or spray coating processes to apply antibacterial properties to substrates such as glass, aluminum plates, plastics, rubber, and wood, reducing bacterial transmission. Attached image description:

[0019] Figure 1 This is the antibacterial cycle diagram of Example 1.

[0020] Figure 2 This is a graph showing the survival rate of methicillin-resistant Staphylococcus aureus (MRSA) inactivated under light conditions in four examples.

[0021] Figure 3 This is a bacterial density diagram of methicillin-resistant Staphylococcus aureus inactivated under light conditions in four examples.

[0022] Figure 4 This is a plate photograph of methicillin-resistant Staphylococcus aureus inactivated under light conditions, as shown in Example 1.

[0023] Figure 5 This is a plate photograph of methicillin-resistant Staphylococcus aureus inactivated under light conditions, as shown in Example 2.

[0024] Figure 6This is a plate photograph of methicillin-resistant Staphylococcus aureus inactivated under light conditions, as shown in Example 3.

[0025] Figure 7 This is a plate photograph of the inactivation of methicillin-resistant Staphylococcus aureus under light conditions in Example 4.

[0026] Figure 8 These are the infrared spectra of Tin reagent, 2,5-dibromo-3-carboxythiophene, and PD-COOH reagent. Detailed Implementation

[0027] Example 1:

[0028] Tin reagent (143 mg), 2,5-dibromo-3-carboxythiophene (87 mg), tetrakis(triphenylphosphine)palladium (31.47 mg), dehydrated and deoxygenated toluene (40 mL), and DMF (8 mL) were added to a double-necked flask under nitrogen protection. The reaction was carried out at 100 °C for 48 h with a stirring speed of 800 r / min. After the reaction was completed and the reaction solution was cooled to room temperature, it was transferred to a round-bottom flask for rotary evaporation. Ethanol was added to precipitate the solid, which was then filtered to obtain the solid. The solid was then extracted with ethanol and acetone to remove impurities and dried to obtain the product PD-COOH.

[0029] A PVA aqueous solution (8 wt%) was prepared in advance. The mixed solvent was adjusted to acidity with 0.5 g concentrated hydrochloric acid in 45 mL of ethanol and 1.8 mL of deionized water. 5 g of TEOS was then added and stirred at room temperature for 3 h to obtain an inorganic silica sol. The PVA aqueous solution and the inorganic silica sol were mixed and stirred, and the mixture was heated to 80 °C. 3 g of NMA was added and stirring continued for 4 h to obtain a hybrid silica sol. A PD-COOH solution in o-dichlorobenzene was added to the hybrid sol, and the mixture was stirred at 60 °C for 9 h. The sol was then coated onto a glass plate and dried at 100 °C for 3 h to obtain hybrid sol coating 1.

[0030] The infrared spectra of the Tin reagent, 2,5-dibromo-3-carboxythiophene, and PD-COOH reagent are as follows: Figure 8 As shown.

[0031] Example 2:

[0032] Tin reagent (143 mg), 2,5-dibromo-3,4-dicarboxythiophene (89 mg), tetrakis(triphenylphosphine)palladium (31.47 mg), dehydrated and deoxygenated toluene (40 mL), and DMF (8 mL) were added to a double-necked flask under nitrogen protection. The reaction was carried out at 120 °C for 72 h with a stirring speed of 800 r / min. After the reaction was completed and the reaction solution was cooled to room temperature, it was transferred to a round-bottom flask for rotary evaporation. Ethanol was added to precipitate the solid, which was then filtered to obtain the solid. The solid was then extracted with ethanol and acetone to remove impurities, and dried to obtain the product PD-(COOH)2.

[0033] A 5 wt% PVA aqueous solution was prepared beforehand. The mixed solvent was adjusted to acidity with 0.5 g concentrated hydrochloric acid in 45 mL of ethanol and 1.8 mL of deionized water. 5 g of TEOS was then added and stirred at room temperature for 5 h to obtain an inorganic silica sol. The PVA aqueous solution and the inorganic silica sol were mixed and stirred, then heated to 80 °C. 3 g of NMA was added and stirring continued for 5 h to obtain a hybrid silica sol. A solution of o-dichlorobenzene in PD-(COOH)₂ was added to the hybrid sol, and the mixture was stirred at 60 °C for 11 h. The sol was then coated onto a glass plate and dried at 100 °C for 4 h to obtain hybrid sol coating 2.

[0034] Example 3:

[0035] Tin reagent (143 mg), 2,5-dibromo-3-carboxythiophene (87 mg), tetrakis(triphenylphosphine)palladium (31.47 mg), dehydrated and deoxygenated toluene (40 mL), and DMF (8 mL) were added to a double-necked flask under nitrogen protection. The reaction was carried out at 100 °C for 72 h with a stirring speed of 800 r / min. After the reaction was completed and the reaction solution was cooled to room temperature, it was transferred to a round-bottom flask for rotary evaporation. Ethanol was added to precipitate the solid, which was then filtered to obtain the solid. The solid was then extracted with ethanol and acetone to remove impurities and dried to obtain the product PD-COOH.

[0036] A PVA aqueous solution (8 wt%) was prepared. The mixed solvent was adjusted to acidity with 0.5 g concentrated hydrochloric acid in 45 mL of ethanol and 1.8 mL of deionized water. Then, 5 g of TEOS and 5 g of TBOT were added, and the mixture was stirred at room temperature for 5 h to obtain an inorganic silicon-titanium sol. The PVA aqueous solution and the inorganic silicon sol were mixed and stirred, then heated to 80 °C. 4 g of MBA was added, and stirring continued for 5 h. A PD-COOH solution in o-dichlorobenzene was added to the hybrid sol, and the mixture was stirred at 60 °C for 11 h. The sol was then coated onto a glass plate and dried at 100 °C for 4 h to obtain the hybrid sol coating 3.

[0037] Example 4:

[0038] Tin reagent (143 mg), 2,5-dibromo-3,4-dicarboxythiophene (89 mg), tetrakis(triphenylphosphine)palladium (31.47 mg), dehydrated and deoxygenated toluene (40 mL), and DMF (8 mL) were added to a double-necked flask under nitrogen protection. The reaction was carried out at 120 °C for 72 h with a stirring speed of 800 r / min. After the reaction was completed and the reaction solution was cooled to room temperature, it was transferred to a round-bottom flask for rotary evaporation. Ethanol was added to precipitate the solid, which was then filtered to obtain the solid. The solid was then extracted with ethanol and acetone to remove impurities, and dried to obtain the product PD-(COOH)2.

[0039] A 5 wt% PVA aqueous solution was prepared. The mixed solvent was adjusted to acidity with 0.5 g concentrated hydrochloric acid in 45 mL of ethanol and 1.8 mL of deionized water. 5 g TEOS and 5 g TBOT were then added, and the mixture was stirred at room temperature for 4 h to obtain an inorganic silicon-titanium sol. The PVA aqueous solution and the inorganic silicon sol were mixed and stirred, then heated to 80 °C. 4 g MBA was added, and stirring continued for 5 h. A PD-COOH solution in o-dichlorobenzene was added to the hybrid sol, and the mixture was stirred at 60 °C for 12 h. The sol was then coated onto a glass plate and dried at 100 °C for 3 h to obtain the hybrid sol coating 4.

[0040] Example 5

[0041] Photocatalytic antibacterial experiment procedure and results: Bacteria were placed in TSB medium and incubated in a shake flask at 37°C until they reached a fixed growth stage. The bacterial suspension was centrifuged at 10,000 rpm for 3 minutes using a refrigerated centrifuge, and the precipitate contained bacteria. The precipitate was washed three times and diluted with PBS (pH 7.0) to a total bacterial concentration of 1 × 10⁻⁶. 7 cfu mL -1 The PCX-50C multichannel photochemical reaction system (Beijing Light, 450–465 nm, light source intensity 100 mW cm⁻¹) was used. 2 Using a white LED as the light source, a photocatalytic antibacterial experiment was conducted by irradiating the reaction solution. Every half hour, 0.4 mL of the reaction solution was pipetted out, diluted with PBS, and scratched on a TSA plate. The relative viability and cell density decrease after overnight incubation at 37°C were calculated using cell counting. All experiments were repeated three times to ensure the validity of the test. Plate photographs of the inactivation of methicillin-resistant Staphylococcus aureus under light irradiation conditions in the above four examples are shown below. Figures 4-7 As shown, the results indicate that Example 1 exhibits the most superior photocatalytic sterilization effect, capable of killing 7 log bacteria (e.g., ...) within 2 hours. Figure 3 As shown in Table 1), the inhibition rates against MRSA and E. coli reached 98% and 95%, respectively (as shown in Table 1). Figure 2 (As shown). An antibacterial cycle test was performed on Example 1 (e.g. Figure 1 As shown in the figure, the results indicate that Example 1 achieved cyclic stability for 5 cycles.

[0042] Table 1. Bactericidal time and number of Staphylococcus aureus and Escherichia coli, antibacterial rate and cyclic stability of antimicrobial agents prepared in different embodiments against Staphylococcus aureus and Escherichia coli.

[0043]

[0044]

Claims

1. A method for preparing a hybrid silica sol photocatalytic antibacterial coating, comprising the following steps: 1) preparing a polymer: Tin reagent, carboxyl dibromothiophene, catalyst, deoxygenated anhydrous toluene and deoxygenated and dehydrated DMF are used as raw materials in a mass ratio of 4:3:1:51:20, and are added to a two-necked flask under N2 protection, the temperature is controlled at 100-120℃, the reaction time is controlled at 48-72 h, the stirring speed is 800 r / min, after the reaction is completed, the reaction solution is cooled to room temperature, and then is moved into a gourd-shaped bottle for rotary evaporation, and then is filtered after being precipitated by adding ethanol, and then is impurity-removed by ethanol and acetone, and finally is dried to obtain a thiophene-based polymer; wherein the Tin reagent is 5,5'-bis(trimethylstannyl)-2,2'-bithiophene, the catalyst is tetrakis(triphenylphosphine)palladium, and the carboxyl dibromothiophene is 2,5-dibromo-3-carboxylthiophene or 2,5-dibromo-3,4-dicarboxylthiophene; when the carboxyl dibromothiophene is 2,5-dibromo-3-carboxylthiophene, the obtained thiophene-based polymer is PD-COOH; when the carboxyl dibromothiophene is 2,5-dibromo-3,4-dicarboxylthiophene, the obtained thiophene-based polymer is PD-(COOH)2; 2) preparing a hybrid sol: PVA, TEOS or / and TBOT and a capping agent are used as raw materials in a mass ratio of 10:4:3, and a hydrolysis method and a thermal polymerization method are adopted for preparation; first, a PVA aqueous solution with a concentration of 1 wt%-8 wt% is prepared, then ethanol, deionized water and 12 mol / L concentrated hydrochloric acid are mixed in a mass ratio of 360:18:5, and then TEOS or / and TBOT is added, and the mixed solvent:TEOS or / and TBOT is mixed in a mass ratio of 5:1, and is stirred at room temperature for 3-5 h to obtain an inorganic sol; the PVA aqueous solution and the inorganic sol are mixed and stirred in a mass ratio of 3:1, the capping agent is added after being heated to 80℃, the mass ratio of the capping agent to PVA is 1-10:25, and the stirring is continued for 4-5 h to obtain an inorganic hybrid sol; wherein the PVA is PVA-1788, and the capping agent is one or a mixture of both of N-hydroxymethyl acrylamide and N,N'-methylene bisacrylamide; 3) preparing an antibacterial sol coating by bonding between the polymer and the hybrid silica sol by using a thermal polymerization method: the thiophene-based polymer o-dichlorobenzene solution is added to the inorganic hybrid sol, and is stirred at 60℃ for 9-12 h, and then the sol is coated on a glass plate, and is dried at 100℃ for 3-4 h to obtain a hybrid silica sol photocatalytic antibacterial coating; the hybrid silica sol photocatalytic antibacterial coating uses the thiophene-based polymer as an active component, and uses the inorganic hybrid sol as a carrier, the thiophene-based polymer is PD-(COOH)2 or PD-COOH, and has no fixed morphology; the carrier is an inorganic hybrid silica sol or an inorganic hybrid silica-titanium sol, and the mass ratio of the thiophene-based polymer to the inorganic hybrid sol is 3-5:

7.

2. The method for preparing a hybrid silica sol photocatalytic antibacterial coating according to claim 1, characterized in that, The thiophene-based polymer is PD-COOH, and the inorganic hybrid sol is an inorganic hybrid silica sol.

3. The method for preparing a hybrid silica sol photocatalytic antibacterial coating according to claim 1, characterized in that, The carboxythiophene dibromide in step 1) is 2,5-dibromo-3-carboxythiophene and the capping agent in step 2) is N-hydroxymethyl acrylamide.

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