Super-hydrophobic antibacterial coating and preparation method thereof
By constructing a superhydrophobic antibacterial coating of oregano oil@SiO2 microcapsules and polydimethylsiloxane on a substrate, the problems of functional synergy failure and poor environmental performance of existing coatings are solved, achieving a highly efficient and environmentally friendly antibacterial effect, suitable for paper, plastic and metal substrates.
Patent Information
- Application Number
- CN202511210893.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-27
- Publication Date
- 2025-10-17
AI Technical Summary
Existing superhydrophobic antibacterial coatings suffer from problems such as functional synergy failure, antibacterial agent burst release, and poor environmental performance. In particular, low drug loading and fluorine pollution limit their application range and long-term effectiveness.
A method for preparing oregano oil@SiO2 microcapsules was adopted. A superhydrophobic antibacterial coating was constructed by spraying an aqueous polyacrylate emulsion, oregano oil@SiO2 microcapsules and polydimethylsiloxane solution onto a substrate. The microcapsules were used as antibacterial active substances and micro-nano rough structural units to replace fluorine-containing substances, thereby improving drug loading and environmental friendliness.
It achieves long-lasting antibacterial effects, increases drug loading, reduces fluoride pollution, is suitable for various substrates, and possesses self-cleaning and highly effective antibacterial properties, while also being safe and environmentally friendly.
Smart Images
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of functional packaging and relates to a super-hydrophobic antibacterial coating and a preparation method thereof. BACKGROUND
[0002] With the improvement of public health awareness, antibacterial coatings are widely used in the packaging field due to their simple process and strong universality. Among them, the super-hydrophobic surface can significantly reduce the initial adhesion rate of bacteria (> 90%) by the Cassie-Baxter effect generated by the micro-nano structure, and effectively block the formation of biofilm. The integration of antibacterial agents and super-hydrophobic coatings can form a "physical barrier-chemical killing" dual-mode protection mechanism: the super-hydrophobic structure reduces bacterial adhesion, and the bactericide actively kills a small amount of adherent bacteria or planktonic bacteria in contact with the surface, providing an efficient and comprehensive solution for antibacterial protection, and showing great potential in ensuring public health safety.
[0003] However, the existing super-hydrophobic antibacterial coating has exposed two outstanding problems in practical application. On the one hand, the function synergy fails. The antibacterial agent has a burst release phenomenon, which leads to rapid depletion of short-term activity and cannot continuously exert antibacterial effect; at the same time, the interface between the hydrophobic component and the antibacterial agent is not compatible, which causes the coating to separate, destroys the overall structure and performance of the coating, and reduces the antibacterial effect. On the other hand, there is a contradiction between long-term effectiveness and environmental protection. The existing slow-release super-hydrophobic coating relies on fluorine-containing compounds (such as perfluoroalkyl substances PFAS), which have biological accumulation toxicity and pose potential threats to the environment and human health; moreover, the antibacterial agent loading system is limited by the insufficient specific surface area of the carrier, resulting in too little drug loading, which is difficult to meet the long-term antibacterial demand, and limits the further promotion and application of the super-hydrophobic antibacterial coating.
[0004] In view of the above problems, the current method is to load the antibacterial agent and then prepare the super-hydrophobic antibacterial coating, mainly in two ways. One is the high molecular grafting type, in which the antibacterial agent is covalently grafted on the film-forming resin, and then a micro-nano rough structure is constructed to prepare the coating. However, this technology is only suitable for polar surfaces, has strict requirements for the substrate, and has the problem of limited substrate, which limits its application range. The second is the inorganic particle loading type, in which inorganic particles (such as SiO2, ZnO, TiO2) are used to load the antibacterial agent, which is then added to the fluorine-containing resin to prepare the coating. This technology solves some problems to a certain extent, but still has the problem of low drug loading, which cannot meet the high-intensity antibacterial demand; at the same time, the pollution problem of fluorine-containing substances still exists, which has adverse effects on the environment, and has not fundamentally solved the difficulties faced by the existing super-hydrophobic antibacterial coating. SUMMARY
[0005] In view of the problems in the prior art, the present application provides a super-hydrophobic antibacterial coating and a preparation method thereof, thereby solving the technical problems of the super-hydrophobic antibacterial coating in the prior art, i.e., the functional synergy failure, the long-term effectiveness and environmental protection contradiction.
[0006] The present application is realized by the following technical solutions: The preparation method of the super-hydrophobic antibacterial coating comprises the following steps: S1: Hexadecyl trimethyl ammonium bromide and trimethoxyphenylsilane are added to water, stirred until fully dissolved, and oregano essential oil is added to obtain an emulsion, the pH value of the emulsion is adjusted to 10-10.5, a mixed solution of anhydrous ethanol and tetraethyl orthosilicate is added, and stirring reaction is performed to prepare oregano essential oil@SiO2 microcapsules; S2: A water-based polyacrylate emulsion is first sprayed on a substrate, once dried, an anhydrous ethanol dispersion solution of the oregano essential oil@SiO2 microcapsules is sprayed, twice dried, a n-hexane solution of polydimethylsiloxane is sprayed, thrice dried, and the super-hydrophobic antibacterial coating is prepared.
[0007] Preferably, the mass of the hexadecyl trimethyl ammonium bromide accounts for 3-9% of the total mass of the hexadecyl trimethyl ammonium bromide, the trimethoxyphenylsilane, the oregano essential oil and the tetraethyl orthosilicate.
[0008] Preferably, the mass of the trimethoxyphenylsilane accounts for 3-12% of the total mass of the hexadecyl trimethyl ammonium bromide, the trimethoxyphenylsilane, the oregano essential oil and the tetraethyl orthosilicate.
[0009] Preferably, in step S1, the amount ratio of water to anhydrous ethanol is (15-35) g:(5-20) mL.
[0010] Preferably, the volume ratio of the oregano essential oil to the tetraethyl orthosilicate is (0.1-1.0) mL:(0.8-2.4) mL.
[0011] Preferably, the spraying amount of the water-based polyacrylate emulsion is 0.03-0.1 g / cm 2 .
[0012] Preferably, the concentration of the anhydrous ethanol dispersion solution of the oregano essential oil@SiO2 microcapsules is 0.01-0.06 g / mL, and the spraying amount of the anhydrous ethanol dispersion solution of the oregano essential oil@SiO2 microcapsules is 0.1-0.15 g / cm 2 .
[0013] Preferably, the concentration of the n-hexane solution of polydimethylsiloxane is 0.05-0.2 g / mL, and the spraying amount of the n-hexane solution of polydimethylsiloxane is 0.05-0.1 g / cm 2 .
[0014] Preferably, the substrate is paper, glass or metal.
[0015] The super-hydrophobic antibacterial coating is prepared by the method, the water contact angle of the super-hydrophobic antibacterial coating is 150-160 degrees, and the inhibition rates of Escherichia coli and Staphylococcus aureus are both more than 99%.
[0016] Compared with the prior art, the present application has the following beneficial technical effects: The application discloses a preparation method of a super-hydrophobic antibacterial coating. The coating is prepared by coating oregano essential oil with SiO2 to prepare oregano essential oil@SiO2 microcapsules. The microcapsules can release the antibacterial agent oregano essential oil for a long time, solve the problem of burst release of the antibacterial agent, and also serve as building blocks of micro-nano rough structures to produce a super-hydrophobic effect, thereby improving the defect that the physical mixing of the antibacterial agent and the hydrophobic component in a traditional coating leads to the failure of function synergy. Meanwhile, polydimethylsiloxane is used as a low-surface-energy substance to replace fluorine-containing substances, thereby reducing PFAS pollution, and the super-hydrophobic coating is constructed by stacking the microcapsules, and can be applied to various substrates such as paper, plastic and metal. In addition, polydimethylsiloxane is certified by FDA 21 CFR 175.300 for food contact, and oregano essential oil meets the GRAS standard (FDA 182.20), so that the coating has significant advantages in safety and environmental friendliness.
[0017] Further, the mass of the cetyltrimethylammonium bromide accounts for 3-9% of the total mass of the cetyltrimethylammonium bromide, the trimethyloxyphenylsiloxane, the oregano essential oil and the tetraethyl orthosilicate. The cetyltrimethylammonium bromide (CTAB) serves as a cationic surfactant and plays a stabilizing role in the emulsion system. When the mass ratio is controlled to be 3-9%, a stable emulsion template can be formed, and the emulsion viscosity is too high (easy to agglomerate) or the emulsion droplets are unstable (easy to break) due to excessive CTAB can be avoided. The appropriate amount of CTAB can also adjust the pore structure of the SiO2 shell to ensure the effective encapsulation of the oregano essential oil, and avoid the negative impact of the surfactant residue on the hydrophobicity of the coating, so that the uniform dispersion and long-term release function of the microcapsules are finally realized.
[0018] Further, the mass of trimethoxyl phenyl siloxane (TMPSiO) accounts for 3% to 12% of the total mass of cetyltrimethylammonium bromide, trimethoxyl phenyl siloxane, oregano essential oil and tetraethyl orthosilicate, TMPSiO participates in the synthesis of the SiO2 shell as a co-precursor, and the mass ratio affects the chemical composition and structure of the shell. The use amount of 3% to 12% can introduce phenyl groups to adjust the hydrophobicity and mechanical strength of the SiO2 shell: the hydrophobicity of the phenyl group helps to improve the compatibility of the microcapsule with the PDMS top coating; and the appropriate amount of TMPSiO can also optimize the porosity of the shell, control the release rate of oregano essential oil (avoid burst release), and at the same time, enhance the wear resistance of the microcapsule and prolong the service life of the coating.
[0019] Further, in step S1, the ratio of the amount of water to the amount of anhydrous ethanol is (15-35) g:(5-20) mL, and the ratio of water to ethanol directly affects the hydrolysis and condensation rate of tetraethyl orthosilicate (TEOS). Water is an essential medium for hydrolysis reaction, and the use amount of 15-35 g can ensure sufficient hydrolysis of TEOS; ethanol as a co-solvent 5-20 mL can adjust the polarity of the reaction system to avoid local rapid hydrolysis of TEOS leading to precipitation. This ratio range can not only ensure the uniform formation of the SiO2 shell, but also control the reaction rate to avoid microcapsule agglomeration, and finally form microcapsules with uniform particle size and dense structure.
[0020] Further, the volume ratio of oregano essential oil to tetraethyl orthosilicate is (0.1-1.0) mL:(0.8-2.4) mL, which balances the amount of core material (oregano essential oil) and shell material (TEOS) and directly affects the encapsulation efficiency and shell thickness of the microcapsule. Excessive oregano essential oil will result in a too thin shell, and the microcapsule is easy to break (release too fast); excessive TEOS will result in a too thick shell (release too slow), and may reduce the mechanical stability of the microcapsule due to increased shell brittleness. The optimized ratio can achieve efficient encapsulation and controlled release of oregano essential oil while ensuring that the microcapsule has sufficient strength to adapt to the spraying process.
[0021] Further, the spraying amount of the water-based polyacrylate emulsion is 0.03-0.1 g / cm 2 The spraying amount of the primer layer directly affects the adhesion of the coating to the substrate, and the use amount of 0.03-0.1 g / cm 2 can form a uniform adhesive layer, which not only avoids the problem of too thick coating (easy to crack) caused by excessive amount, but also prevents the problem of poor adhesion (easy to fall off) caused by insufficient amount, and this range ensures that the coating has excellent friction resistance and weather resistance on various substrates such as paper, plastic and metal, providing a stable foundation for the subsequent loading of functional layers.
[0022] Further, the concentration of the oregano essential oil@SiO2 microcapsule ethanol dispersion solution is 0.01-0.06 g / mL, and the spraying amount of the oregano essential oil@SiO2 microcapsule ethanol dispersion solution is 0.1-0.15 g / cm 2 The concentration of 0.01-0.06 g / mL can avoid microcapsule agglomeration (too high concentration) or sparse distribution (too low concentration); and the spraying amount of 0.1-0.15 g / cm 2 ensures that the microcapsules form a dense stacking structure on the surface of the substrate, which not only builds the required micro-nano roughness for super-hydrophobicity, but also provides sufficient antibacterial agent content to achieve the synergistic function of antibacterial and hydrophobicity.
[0023] Further, the concentration of the polydimethylsiloxane n-hexane solution is 0.05-0.2 g / mL, and the spraying amount of the polydimethylsiloxane n-hexane solution is 0.05-0.1 g / cm 2 As a low surface energy material, the concentration and spraying amount of PDMS directly affect the super-hydrophobicity of the coating, and the concentration of 0.05-0.2 g / mL can ensure that PDMS uniformly covers the surface of the microcapsules, avoiding the problem of too thick coating (affecting roughness) caused by too high concentration or insufficient reduction of surface energy caused by too low concentration; and the spraying amount of 0.05-0.1 g / cm 2 further optimizes the surface energy, so that the coating has self-cleaning property (water droplets roll down and carry away dirt), and replaces fluorine-containing substances, meeting the environmental protection requirements. BRIEF DESCRIPTION OF DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.
[0025] Figure 1 TEM photo of oregano essential oil@SiO2 microcapsules prepared in Example 3 of the present application; Figure 2 Antibacterial effect of oregano essential oil@SiO2 microcapsules prepared in Example 4 of the present application; Figure 3 Water contact angle of the super-hydrophobic antibacterial coating prepared in Example 2 of the present application; Figure 4 Antibacterial effect of the super-hydrophobic antibacterial coating prepared in Example 4 of the present application; Figure 5 Antibacterial adhesion effect of the super-hydrophobic antibacterial coating prepared in Example 4 of the present application; Figure 6SEM photos of the super-hydrophobic antibacterial coating prepared for Example 5 of the present application. DETAILED DESCRIPTION
[0026] To enable persons skilled in the art to understand the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings to those skilled in the art of the present application, and in the event of conflict, the definitions in the present specification shall prevail.
[0027] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting on the scope of the present application, i.e., the present application can be practiced without regard to any particular theory or mechanism.
[0028] Herein, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, amounts, contents and concentrations, are for the sake of brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).
[0029] Herein, unless otherwise specified, "comprise", "include", "contain", "have" or similar words encompass the meaning of "consist of" and "consist essentially of", for example, "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".
[0030] Herein, for the sake of brevity, all possible combinations of the technical features in various embodiments or examples are not described. Therefore, as long as the combinations of the technical features do not contradict each other, the technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered as the scope of the present specification.
[0031] The present application provides a method for preparing a super-hydrophobic antibacterial coating, comprising the following steps: (1) Preparation of oregano essential oil@SiO2 microcapsules Hexadecyl trimethyl ammonium bromide and trimethoxyphenylsilane were added to water, stirred until fully dissolved, then oregano essential oil was added, and stirring was continued to obtain an emulsion. The pH value of the emulsion was adjusted to 10-10.5, then a mixed solution of anhydrous ethanol and tetraethyl orthosilicate was added, and stirring was performed to react, thereby preparing oregano essential oil@SiO2 microcapsules; In one specific embodiment, the step is: adding cetyltrimethylammonium bromide and trimethyloxyphenylsilane into water, stirring until dissolved, and then transferring into a three-necked flask, stirring at 30℃ and a stirring speed of 700-1100 rpm for 0.5 h. Then, using a pipette, adding the oil of oregano into the three-necked flask, and continuing to stir for 0.5 h to obtain an emulsion, and adding ammonia water dropwise to adjust the pH value to 10-10.5. Then, mixing anhydrous ethanol and tetraethyl orthosilicate uniformly, and then adding dropwise into the emulsion, after the dropwise addition is completed, adjusting the stirring speed to 300 rpm, and continuing to react for 3 h. After the reaction is completed, centrifuging to obtain the particles, and then washing once with anhydrous ethanol, twice with deionized water, and freeze-drying to obtain the oil of oregano@SiO2 microcapsules; The mass of the cetyltrimethylammonium bromide accounts for 3%-9% of the total mass of the cetyltrimethylammonium bromide, the trimethyloxyphenylsilane, the oil of oregano, and the tetraethyl orthosilicate; The mass of the trimethyloxyphenylsilane accounts for 3%-12% of the total mass of the cetyltrimethylammonium bromide, the trimethyloxyphenylsilane, the oil of oregano, and the tetraethyl orthosilicate; The amount ratio of the water to the anhydrous ethanol is (15-35) g:(5-20) mL; The volume ratio of the oil of oregano to the tetraethyl orthosilicate is (0.1-1.0) mL:(0.8-2.4) mL; (2) Construction of the super-hydrophobic antibacterial coating First, spraying the water-based polyacrylate emulsion on the substrate, drying once, then spraying the anhydrous ethanol dispersion of the oil of oregano@SiO2 microcapsules, drying twice, then spraying the n-hexane solution of the polydimethylsiloxane, drying three times, and thus obtaining the super-hydrophobic antibacterial coating.
[0032] In one specific embodiment, the step is: weighing 3 g of the water-based polyacrylate emulsion, and then preparing 5 mL of the anhydrous ethanol dispersion of the oil of oregano@SiO2 microcapsules with a concentration of 0.01-0.06 g / mL and 3 mL of the n-hexane solution of the polydimethylsiloxane with a concentration of 0.05-0.2 g / mL. Then, spraying the water-based polyacrylate emulsion on the surface of the paper, placing in an oven, treating at 60℃ for 3-5 min, drying to a semi-dry state, then spraying the anhydrous ethanol dispersion of the oil of oregano@SiO2 microcapsules, drying in the oven for 10 min, and finally spraying the n-hexane solution of the polydimethylsiloxane, and drying to obtain the super-hydrophobic antibacterial paper.
[0033] The substrate can be paper, glass, or metal; The concentration of the anhydrous ethanol dispersion of the oil of oregano@SiO2 microcapsules is 0.01-0.06 g / mL; The concentration of the n-hexane solution of the polydimethylsiloxane is 0.05-0.2 g / mL.
[0034] The spraying amount of the aqueous polyacrylate emulsion is 0.03-0.1 g / cm 2 ; The spraying amount of the anhydrous ethanol dispersion of the oregano essential oil@SiO2 microcapsule is 0.1-0.15 g / cm 2 ; The spraying amount of the n-hexane solution of the polydimethylsiloxane is 0.05-0.1 g / cm 2 ; In addition, the application further discloses an ultrahydrophobic antibacterial coating prepared by the method, the water contact angle of the ultrahydrophobic antibacterial coating is 150-160 degrees; and the inhibition rates of the ultrahydrophobic antibacterial coating on escherichia coli and staphylococcus aureus are both more than 99%.
[0035] The application discloses a preparation method of an ultrahydrophobic antibacterial coating based on oregano essential oil@SiO2 microcapsules.
[0036] The application discloses a kind of based on oregano essential oil SiO2 Microcapsule Super-hydrophobic antibacterial coating and preparation method thereof, it belongs to functional packaging material and functional coating material technical field.First, the preparation of oregano essential oil SiO2 Microcapsule is combined with oil-in-water method and sol-gel method.Then, through layer-by-layer spraying method constructs coating: with oregano essential oil SiO2 Microcapsule forms rough micro-nano structure, and with polydimethylsiloxane as low surface energy substance, jointly constructs super-hydrophobic antibacterial coating.Oregano essential oil SiO2 Microcapsule in the obtained essential oil load rate is 25%~28%, and its antibacterial rate to escherichia coli and staphylococcus aureus is all more than 99%.The water contact angle of the super-hydrophobic antibacterial coating constructed is 154.1 degrees.The antibacterial circle diameter of the coating to staphylococcus aureus and escherichia coli is 10 mm, 5 mm respectively.Compared with the original paper without coating, the anti-adhesion effect of the coated paper to staphylococcus aureus and escherichia coli is also significant, more than 99%.
[0037] The application will be further described below in connection with specific examples. It should be understood that the examples are only used to illustrate the application but not used to limit the scope of the application. In addition, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content of the application, and these equivalent forms also fall within the scope defined by the appended claims of the application.
[0038] The following examples use conventional apparatus in the art. Unless otherwise specified, the experimental methods in the following examples are usually carried out under conventional conditions, or under the conditions recommended by the manufacturer. Various raw materials are used in the following examples, unless otherwise specified, and conventional commercially available products are used, which are conventional specifications in the art. In the specification of the application and the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.
[0039] Example 1 A preparation method of a super-hydrophobic antibacterial coating, comprising the following steps: (1) Preparation of oregano essential oil SiO2 Microcapsule Take 3% of cetyl trimethyl ammonium bromide, 6% of trimethyloxyphenylsiloxane, 25 g of deionized water, dissolve and stir uniformly, then transfer to a three-necked flask, stir at 30°C, stirring speed is 700 rpm for 0.5 h. Then use a pipette to remove 700 μL of oregano oil into the three-necked flask, continue to stir for 0.5 h, get emulsion, add ammonia water to adjust pH to 10~10.5. Then mix 10 mL of anhydrous ethanol and 1.4 mL of tetraethyl orthosilicate uniformly, drop into the emulsion in the three-necked flask, after the end of the drop, adjust the stirring speed to 300 rpm, continue to react for 3 h. After the reaction is completed, centrifuge to obtain particles, then use anhydrous ethanol to centrifuge and wash once, deionized water to centrifuge and wash twice, freeze-drying to obtain oregano oil@SiO2 microcapsules.
[0040] (2) Construction of super-hydrophobic antibacterial coating Take 3 g of water-based polyacrylate emulsion, then prepare 5 mL of 0.06 g / mL oregano oil@SiO2 microcapsule anhydrous ethanol dispersion and 3 mL of 0.2 g / mL polydimethylsiloxane n-hexane solution. Then spray the water-based polyacrylate emulsion on the surface of the paper, dry in the oven to semi-dry state, then spray the oregano oil@SiO2 microcapsule anhydrous ethanol dispersion, dry in the oven for 10 min, finally spray the polydimethylsiloxane n-hexane solution, dry, to obtain super-hydrophobic antibacterial paper.
[0041] Example 2 A method for preparing a super-hydrophobic antibacterial coating, comprising the following steps: (1) Preparation of oregano oil@SiO2 microcapsules Take 5% of cetyl trimethyl ammonium bromide, 6% of trimethyloxyphenylsiloxane, 30 g of deionized water, dissolve and stir uniformly, then transfer to a three-necked flask, stir at 30°C, stirring speed is 700 rpm for 0.5 h. Then use a pipette to remove 700 μL of oregano oil into the three-necked flask, continue to stir for 0.5 h, get emulsion, add ammonia water to adjust pH to 10~10.5. Then mix 5 mL of anhydrous ethanol and 1.4 mL of tetraethyl orthosilicate uniformly, drop into the emulsion in the three-necked flask, after the end of the drop, adjust the stirring speed to 300 rpm, continue to react for 3 h. After the reaction is completed, centrifuge to obtain particles, then use anhydrous ethanol to centrifuge and wash once, deionized water to centrifuge and wash twice, freeze-drying to obtain oregano oil@SiO2 microcapsules.
[0042] (2) Construction of super-hydrophobic antibacterial coating Weigh 3 g of a water-based polyacrylate emulsion, then mix it with 5 mL of a 0.06 g / mL dispersion of oregano essential oil@SiO2 microcapsules in anhydrous ethanol and 3 mL of a 0.2 g / mL solution of polydimethylsiloxane in n-hexane. The water-based polyacrylate emulsion was first sprayed onto the paper surface, oven-dried until semi-dry. Next, the oregano essential oil@SiO2 microcapsules in anhydrous ethanol dispersion was sprayed on. After oven-drying for 10 minutes, the polydimethylsiloxane solution in n-hexane was finally sprayed on and dried to create superhydrophobic, antibacterial paper.
[0043] Example 3 A method for preparing a super-hydrophobic antibacterial coating comprises the following steps: (1) Preparation of oregano essential oil@SiO2 microcapsules 5% hexadecyltrimethylammonium bromide, 6% trimethyloxyphenylsiloxane, and 25 g of deionized water were weighed, dissolved, and stirred thoroughly. The mixture was then transferred to a three-necked flask and stirred at 30°C and 900 rpm for 0.5 h. 1000 μL of oregano essential oil was then pipetted into the flask and stirred for 0.5 h to obtain an emulsion. Ammonia was then added dropwise to adjust the pH to 10–10.5. 10 mL of anhydrous ethanol and 1.4 mL of ethyl orthosilicate were then dropwise mixed and added to the emulsion in the flask. After the addition was complete, the stirring speed was adjusted to 300 rpm and the reaction continued for 3 h. After the reaction was completed, the particles were centrifuged and washed once with anhydrous ethanol and twice with deionized water. The resulting oregano essential oil@SiO2 microcapsules were freeze-dried. (2) Construction of superhydrophobic antibacterial coating Weigh 3 g of a water-based polyacrylate emulsion, then mix it with 5 mL of a 0.06 g / mL dispersion of oregano essential oil@SiO2 microcapsules in anhydrous ethanol and 3 mL of a 0.2 g / mL solution of polydimethylsiloxane in n-hexane. The water-based polyacrylate emulsion was first sprayed onto the paper surface, oven-dried until semi-dry. Next, the oregano essential oil@SiO2 microcapsules in anhydrous ethanol dispersion was sprayed on. After oven-drying for 10 minutes, the polydimethylsiloxane solution in n-hexane was finally sprayed on and dried to create superhydrophobic, antibacterial paper.
[0044] Example 4 A method for preparing a super-hydrophobic antibacterial coating comprises the following steps: (1) Preparation of oregano essential oil@SiO2 microcapsules Take 5% of cetyl trimethyl ammonium bromide, 6% of trimethyloxyphenylsiloxane, 25 g of deionized water, dissolve and stir uniformly, then transfer to a three-necked flask, stir at 30°C, stirring speed is 700 rpm for 0.5 h. Then use a pipette to remove 700 μL of oregano oil into the three-port, continue to stir for 0.5 h, get emulsion, dropwise addition of ammonia to adjust the pH to 10~10.5. Then mix 10 mL of anhydrous ethanol and 1.4 mL of tetraethyl orthosilicate uniformly, dropwise add to the emulsion in the three-necked flask, after the end of dropwise addition, adjust the stirring speed to 300 rpm, continue to react for 3 h. After the reaction is completed, centrifuge to obtain particles, then use anhydrous ethanol to centrifuge once, deionized water to centrifuge twice, freeze-drying to obtain oregano oil@SiO2microcapsules (2) Construction of super-hydrophobic antibacterial coating Take 3 g of water-based polyacrylate emulsion, then prepare 5 mL of 0.03 g / mL oregano oil@SiO2microcapsule anhydrous ethanol dispersion and 3 mL of 0.2 g / mL polydimethylsiloxane n-hexane solution. Then spray the water-based polyacrylate emulsion on the surface of the paper, dry in the oven to semi-dry state, then spray the oregano oil@SiO2microcapsule anhydrous ethanol dispersion, dry in the oven for 10 min, finally spray the polydimethylsiloxane n-hexane solution, dry, to obtain super-hydrophobic antibacterial paper.
[0045] Example 5 A method for preparing a super-hydrophobic antibacterial coating, comprising the following steps: (1) Preparation of oregano oil@SiO2microcapsules Take 5% of cetyl trimethyl ammonium bromide, 6% of trimethyloxyphenylsiloxane, 25 g of deionized water, dissolve and stir uniformly, then transfer to a three-necked flask, stir at 30°C, stirring speed is 700 rpm for 0.5 h. Then use a pipette to remove 700 μL of oregano oil into the three-port, continue to stir for 0.5 h, get emulsion, dropwise addition of ammonia to adjust the pH to 10~10.5. Then mix 10 mL of anhydrous ethanol and 1.4 mL of tetraethyl orthosilicate uniformly, dropwise add to the emulsion in the three-necked flask, after the end of dropwise addition, adjust the stirring speed to 300 rpm, continue to react for 3 h. After the reaction is completed, centrifuge to obtain particles, then use anhydrous ethanol to centrifuge once, deionized water to centrifuge twice, freeze-drying to obtain oregano oil@SiO2microcapsules (2) Construction of super-hydrophobic antibacterial coating Take 3 g of water-based polyacrylate emulsion, and then prepare 5 mL of 0.06 g / mL oregano oil@SiO2 microcapsule dispersion in anhydrous ethanol and 3 mL of 0.1 g / mL polydimethylsiloxane solution in n-hexane. Then, the water-based polyacrylate emulsion is sprayed on the surface of the paper, dried in an oven to a semi-dry state, then the oregano oil@SiO2 microcapsule dispersion in anhydrous ethanol is sprayed, dried in an oven for 10 min, and finally the polydimethylsiloxane solution in n-hexane is sprayed and dried to obtain the super-hydrophobic antibacterial paper.
[0046] Example 6 A method for preparing a super-hydrophobic antibacterial coating, comprising the following steps: (1) Preparation of oregano oil@SiO2 microcapsules Hexadecyl trimethyl ammonium bromide and trimethoxyphenylsilane are added to 15 g of water, stirred until dissolved, and then transferred to a three-necked flask. Stirring is carried out at 30°C and a stirring speed of 700 rpm for 0.5 h. Then, 0.1 mL of oregano oil is added to the three-necked flask using a pipette, and stirring is continued for 0.5 h to obtain an emulsion. Ammonia water is added dropwise to adjust the pH value to 10. Then, 5 mL of anhydrous ethanol and 0.8 mL of tetraethyl orthosilicate are mixed uniformly and added dropwise to the emulsion. After the addition is completed, the stirring speed is adjusted to 300 rpm, and the reaction is continued for 3 h. After the reaction is completed, the particles are obtained by centrifugation, washed once with anhydrous ethanol, and washed twice with deionized water, and then freeze-dried to obtain oregano oil@SiO2 microcapsules. In the above method, the mass of hexadecyl trimethyl ammonium bromide accounts for 3% of the total mass of hexadecyl trimethyl ammonium bromide, trimethoxyphenylsilane, oregano oil, and tetraethyl orthosilicate. In the above method, the mass of trimethoxyphenylsilane accounts for 3% of the total mass of hexadecyl trimethyl ammonium bromide, trimethoxyphenylsilane, oregano oil, and tetraethyl orthosilicate. (2) Construction of a super-hydrophobic antibacterial coating The water-based polyacrylate emulsion is first sprayed on the substrate, treated at 60°C for 3 min, and dried to a semi-dry state. Then, the oregano oil@SiO2 microcapsule dispersion in anhydrous ethanol is sprayed, dried in an oven for 10 min, and then the polydimethylsiloxane solution in n-hexane is sprayed. After drying three times, the super-hydrophobic antibacterial coating is obtained.
[0047] The substrate can be paper, glass, or metal. The concentration of the oregano oil@SiO2 microcapsule dispersion in anhydrous ethanol is 0.01 g / mL. The concentration of the polydimethylsiloxane solution in n-hexane is 0.05 g / mL. The spraying amount of the water-based polyacrylate emulsion is 0.03 g / cm 2 . The spraying amount of the oregano oil@SiO2 microcapsule dispersion in anhydrous ethanol is 0.1 g / cm2 The spraying amount of the polydimethylsiloxane n-hexane solution is 0.05 g / cm 2 ; The water contact angle of the super-hydrophobic antibacterial coating prepared in the embodiment is 151°; the inhibition rates of Escherichia coli and Staphylococcus aureus are both more than 99%.
[0048] Embodiment 7 A method for preparing a super-hydrophobic antibacterial coating comprises the following steps: (1) Preparation of oregano essential oil@SiO2 microcapsules Hexadecyl trimethyl ammonium bromide and trimethoxyphenylsilane were added into 35 g of water, stirred and uniformly dissolved, and then transferred into a three-necked flask, stirred at 30°C and a stirring speed of 1100 rpm for 0.5 h. Then, 1.0 mL of oregano essential oil was taken out by using a pipette and added into the three-necked flask, and the stirring was continued for 0.5 h to obtain an emulsion. Ammonia water was added dropwise to adjust the pH value to 10.5. Then, 20 mL of anhydrous ethanol and 2.4 mL of tetraethyl orthosilicate were mixed uniformly and added dropwise into the emulsion. After the dropwise addition was completed, the stirring speed was adjusted to 300 rpm, and the reaction was continued for 3 h. After the reaction was completed, the particles were obtained by centrifugation, and then washed once with anhydrous ethanol and twice with deionized water, and freeze-dried to obtain the oregano essential oil@SiO2 microcapsules. The mass of the hexadecyl trimethyl ammonium bromide accounts for 9% of the total mass of the hexadecyl trimethyl ammonium bromide, the trimethoxyphenylsilane, the oregano essential oil and the tetraethyl orthosilicate; The mass of the trimethoxyphenylsilane accounts for 12% of the total mass of the hexadecyl trimethyl ammonium bromide, the trimethoxyphenylsilane, the oregano essential oil and the tetraethyl orthosilicate; (2) Construction of a super-hydrophobic antibacterial coating The water-based polyacrylate emulsion was first sprayed on the substrate, treated at 60°C for 5 min, and dried to a semi-dry state. Then, the anhydrous ethanol dispersion of the oregano essential oil@SiO2 microcapsules was sprayed, dried in an oven for 10 min, the n-hexane solution of polydimethylsiloxane was sprayed, and the super-hydrophobic antibacterial coating was prepared after three times of drying.
[0049] The substrate can be paper, glass or metal; the concentration of the anhydrous ethanol dispersion of the oregano essential oil@SiO2 microcapsules is 0.06 g / mL; the concentration of the n-hexane solution of polydimethylsiloxane is 0.2 g / mL; the spraying amount of the water-based polyacrylate emulsion is 0.1 g / cm 2 ; the spraying amount of the anhydrous ethanol dispersion of the oregano essential oil@SiO2 microcapsules is 0.15 g / cm 2 ; the spraying amount of the n-hexane solution of polydimethylsiloxane is 0.1 g / cm 2 ; The water contact angle of the super-hydrophobic antibacterial coating prepared in this embodiment is 160°; the inhibition rates of Escherichia coli and Staphylococcus aureus are both above 99%.
[0050] Embodiment 8 A method for preparing a super-hydrophobic antibacterial coating comprises the following steps: (1) Preparation of oregano essential oil@SiO2 microcapsules Hexadecyl trimethyl ammonium bromide and trimethoxyphenylsilane were added into 30 g of water, stirred until dissolved, and then transferred into a three-necked flask. The mixture was stirred at 30°C and 1000 rpm for 0.5 h. Then, 0.5 mL of oregano essential oil was added into the three-necked flask using a pipette, and the mixture was continuously stirred for 0.5 h to obtain an emulsion. Ammonia water was added dropwise to adjust the pH value to 10. Then, 15 mL of anhydrous ethanol and 1 mL of tetraethyl orthosilicate were mixed uniformly and added dropwise into the emulsion. After the dropwise addition was completed, the stirring speed was adjusted to 300 rpm, and the reaction was continued for 3 h. After the reaction was completed, the particles were obtained by centrifugation, and then washed once with anhydrous ethanol and twice with deionized water. Finally, the oregano essential oil@SiO2 microcapsules were obtained by freeze-drying. In the above method, the mass of hexadecyl trimethyl ammonium bromide accounts for 4% of the total mass of hexadecyl trimethyl ammonium bromide, trimethoxyphenylsilane, oregano essential oil, and tetraethyl orthosilicate. In the above method, the mass of trimethoxyphenylsilane accounts for 5% of the total mass of hexadecyl trimethyl ammonium bromide, trimethoxyphenylsilane, oregano essential oil, and tetraethyl orthosilicate. (2) Construction of a super-hydrophobic antibacterial coating First, a water-based polyacrylate emulsion was sprayed on a substrate, and the substrate was treated at 60°C for 4 min and dried to a semi-dry state. Then, a dispersion of oregano essential oil@SiO2 microcapsules in anhydrous ethanol was sprayed on the substrate, and the substrate was dried in an oven for 10 min. Subsequently, a solution of polydimethylsiloxane in n-hexane was sprayed on the substrate, and the substrate was dried three times to obtain the super-hydrophobic antibacterial coating.
[0051] The substrate can be paper, glass, or metal. The concentration of the dispersion of oregano essential oil@SiO2 microcapsules in anhydrous ethanol is 0.03 g / mL. The concentration of the solution of polydimethylsiloxane in n-hexane is 0.1 g / mL. The spraying amount of the water-based polyacrylate emulsion is 0.05 g / cm 2 . The spraying amount of the dispersion of oregano essential oil@SiO2 microcapsules in anhydrous ethanol is 0.12 g / cm 2 . The spraying amount of the solution of polydimethylsiloxane in n-hexane is 0.08 g / cm 2 . The water contact angle of the super-hydrophobic antibacterial coating prepared in this embodiment is 155°; the inhibition rates of Escherichia coli and Staphylococcus aureus are both above 99%.
[0052] Figure 1 The TEM picture of the oregano essential oil@SiO2 microcapsule prepared in Example 3 of the present application is shown in Figure 2. Figure 1 It can be seen that the oregano essential oil@SiO2 microcapsule has a yolk structure and obvious cavity structure.
[0053] Figure 2 The antibacterial effect of the oregano essential oil@SiO2 microcapsule prepared in Example 4 of the present application is shown in Figure 4. Figure 2 It can be seen that the antibacterial effect of the oregano essential oil@SiO2 microcapsule is excellent, and the inhibition rate of the oregano essential oil@SiO2 microcapsule on E. coli and S. aureus is more than 99%.
[0054] Figure 3 The water contact angle of the super-hydrophobic antibacterial coating prepared in Example 2 of the present application is shown in Figure 3. Figure 3 It can be seen that the water contact angle of the super-hydrophobic antibacterial coating prepared in the present application is 154.1°, and the super-hydrophobic antibacterial coating has excellent hydrophobic property.
[0055] Figure 4 The antibacterial effect of the super-hydrophobic antibacterial coating prepared in Example 4 of the present application is shown in Figure 5. Figure 4 It can be seen that the antibacterial circle size of the super-hydrophobic antibacterial coating prepared in the present application on S. aureus and E. coli is 10 mm and 4 mm, respectively.
[0056] Figure 5 The antibacterial adhesion effect of the super-hydrophobic antibacterial coating prepared in Example 4 of the present application is shown in Figure 6. Figure 5 It can be seen that the antibacterial adhesion of the super-hydrophobic antibacterial coating on S. aureus and E. coli is more than 99%, which indicates that the coating has excellent antibacterial adhesion property.
[0057] Figure 6 The SEM picture of the super-hydrophobic antibacterial coating prepared in Example 5 of the present application is shown in Figure 7. Figure 6 It can be seen that the coating has obvious rough structure due to the stacking of the oregano essential oil@SiO2 microcapsule.
[0058] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.
Claims
1. A method for preparing a super-hydrophobic antibacterial coating, characterized in that: The following steps are involved: S1: adding hexadecyltrimethylammonium bromide and trimethyloxyphenylsiloxane to water, stirring until fully dissolved, adding oregano essential oil to obtain an emulsion, adjusting the pH value of the emulsion to 10-10.5, adding a mixed solution of anhydrous ethanol and ethyl orthosilicate, stirring and reacting, and preparing oregano essential oil@SiO2 microcapsules; S2: First spraying a water-based polyacrylate emulsion on the substrate, drying it once, spraying the anhydrous ethanol dispersion of the oregano essential oil@SiO2 microcapsules, drying it twice, spraying a n-hexane solution of polydimethylsiloxane, and drying it three times to obtain the superhydrophobic antibacterial coating.
2. The method for preparing a super-hydrophobic antibacterial coating according to claim 1, wherein The mass of the cetyltrimethylammonium bromide accounts for 3% to 9% of the total mass of cetyltrimethylammonium bromide, trimethyloxyphenylsiloxane, oregano essential oil and ethyl orthosilicate.
3. The method for preparing a super-hydrophobic antibacterial coating according to claim 1, wherein The mass of trimethyloxyphenylsiloxane accounts for 3% to 12% of the total mass of cetyltrimethylammonium bromide, trimethyloxyphenylsiloxane, oregano essential oil and ethyl orthosilicate.
4. The method for preparing a super-hydrophobic antibacterial coating according to claim 1, wherein In step S1, the usage ratio of water to anhydrous ethanol is (15-35) g:(5-20) mL.
5. The method for preparing a super-hydrophobic antibacterial coating according to claim 1, wherein The volume ratio of oregano essential oil and ethyl orthosilicate is (0.1~1.0) mL:(0.8~2.4) mL.
6. The method for preparing a super-hydrophobic antibacterial coating according to claim 1, wherein The spraying amount of the water-based polyacrylate emulsion is 0.03~0.1 g / cm 2 .
7. The method for preparing a super-hydrophobic antibacterial coating according to claim 1, wherein The concentration of the anhydrous ethanol dispersion of oregano essential oil @ SiO2 microcapsules is 0.01-0.06 g / mL, and the spraying amount of the anhydrous ethanol dispersion of oregano essential oil @ SiO2 microcapsules is 0.1-0.15 g / cm 2 .
8. The method for preparing a super-hydrophobic antibacterial coating according to claim 1, wherein The concentration of the polydimethylsiloxane n-hexane solution is 0.05-0.2 g / mL, and the spraying amount of the polydimethylsiloxane n-hexane solution is 0.05-0.1 g / cm 2 .
9. The method for preparing a super-hydrophobic antibacterial coating according to claim 1, wherein: The substrate is paper, glass or metal.
10. A super hydrophobic antibacterial coating, characterized in that: Prepared by the method according to any one of claims 1 to 9; the water contact angle of the superhydrophobic antibacterial coating is 150° to 160°; and the inhibition rate against Escherichia coli and Staphylococcus aureus is above 99%.