Hydrophobic segment-integrated organic / inorganic hybrid nanoparticles and hydrophobicity conversion coating

Abstract

The application provides a kind of hydrophobic chain segment and response functional group integrated organic / inorganic hybrid nanoparticles and hydrophilic-hydrophobic conversion coating, the integrated organic / inorganic hybrid nanoparticles is by the inorganic nanoparticles with hydroxyl on surface and organic group A or organic group B between by covalent bond connection organic / inorganic hybrid nanoparticles, wherein the proportion of organic group A or organic group B is by thermogravimetric analysis to calculate the graft density characterization, graft density is 8-15g / g.The application mainly through the integration of hydrophobic chain segment and pH response functional group molecular design, and by the regulation of hydrophobic chain length, to control its pH response behavior and hydrophilic-hydrophobic conversion degree, from molecular structure design, for the balance between hydrophobic chain and pH response hydrophilic-hydrophobic conversion provides new insight.

Description

Technical Field

[0001] This invention belongs to the field of intelligent superwetting materials technology, and relates to an organic / inorganic hybrid nanoparticle integrating hydrophobic segments and responsive functional groups and a hydrophilic-hydrophobic conversion coating. Specifically, it relates to an organic / inorganic hybrid nanoparticle integrating hydrophobic segments and responsive functional groups and its preparation method, as well as the preparation of a hydrophobic coating based on the alkyl hydrophobic chain length regulation using the organic / inorganic hybrid nanoparticle integrating hydrophobic segments and responsive functional groups and the application method of the coating. Background Technology

[0002] Wettability is a fundamental property of a solid surface to repel or attract a liquid when in contact with it. Increasing research in industry and academia focuses on simulating the wettability of extreme natural surfaces. Among these, superhydrophobic surfaces have attracted widespread attention in scientific research and daily life due to their unique surface properties, such as self-cleaning, antifouling, antibacterial, and anti-corrosion. Superhydrophobic surfaces are defined as surfaces with a water contact angle greater than 150° and a roll-off angle less than 10°, typically constructed from low surface energy materials and surface micro / nano-level structures. However, traditionally prepared superhydrophobic surfaces often exhibit fixed surface wettability due to their fixed microstructure and chemical composition, failing to adequately meet the demands of practical applications. Therefore, intelligent wetting materials that alternately exhibit surface properties through external stimuli are gaining increasing attention. These intelligent materials with reversible switching wettability, particularly the transition between superwetting and superantiwetting, are of great significance in industrial applications such as microfluidic devices, liquid manipulation, and oil-water separation.

[0003] Stimulus-responsive superhydrophobic materials mainly consist of three parts: low surface energy substances, surface micro / nano rough structures, and stimulus-response factors. Micro / nano hierarchical rough structures and low surface energy substances are necessary conditions for superhydrophobicity, while the response factors generate surface responses under external stimuli. Common external stimuli include magnetism, temperature, light, and pH. When these stimuli act, the surface composition changes under the influence of the response factors, thus switching wettability. pH response, as a common external stimulus, is easy to manipulate and implement. Simply changing the pH value of the material can alter the molecular structure and charge, thus achieving macroscopic wettability switching more easily and conveniently.

[0004] Chinese Patent Publication No. CN110734655A discloses a pH-responsive superhydrophobic coating material, its preparation method, and its application. This coating material is obtained by reacting a stearic acid / nano-titanium dioxide composite with chitosan. The material can change from a superhydrophobic to a superhydrophilic state when the pH is alkaline, and exhibits superhydrophobic properties when the pH is neutral and acidic. Chinese Patent Publication No. CN110642977B discloses the preparation and application of a pH-responsive hydrophobic-oleophobic-hydrophilic-oleophobic reversible material. This material is formed by polymerizing a pH-responsive composition on a substrate surface. The pH-responsive composition includes a pH-responsive monomer, a fluoroalkyl monomer, a crosslinking agent, and a photoinitiator. This hydrophobic-oleophobic material utilizes pH-responsive polymer segments to provide the substrate's pH-responsive function. Under acidic conditions, the amino or pyridine groups in the pH-responsive monomers undergo protonation, enhancing hydrophilicity and transforming the material from hydrophobic-oleophobic to hydrophilic-oleophobic. Conversely, under alkaline conditions, the pH-responsive monomers deprotonate, again transforming the material from hydrophilic-oleophobic to hydrophobic-oleophobic, thus achieving a reversible pH-controlled hydrophobic-oleophobic to hydrophilic-oleophobic transformation. Chinese Patent Publication No. CN112981973A discloses a method for preparing a pH-responsive superhydrophobic material. This method first prepares superhydrophobic silica, then mixes it uniformly with a similarly prepared acrylate copolymer, and sprays it onto a fabric surface to obtain a pH-responsive superhydrophobic material. This material, based on superhydrophobicity, introduces a pH-responsive acrylate copolymer component, achieving wettability conversion within a specific pH range.

[0005] The pH-responsive methods and materials disclosed in the aforementioned patents all exhibit good wetting conversion performance and pH responsiveness. However, the focus of development in these disclosed materials or methods is primarily on their pH responsiveness, switchable wetting properties, and applications. Their structures combine pH-responsive molecules and hydrophobic molecules as two distinct substances. Controlling the reversible wetting conversion behavior is limited by the competition and synergy between the responsive structure and the hydrophobic molecules. The protonable responsive structure is easily masked by migrating hydrophobic segments, resulting in poor response or lack of persistence. There is no further analysis at the molecular structural level of how hydrophobic segments affect pH responsiveness and hydrophilic-hydrophobic conversion. Therefore, developing a method for pH-responsive hydrophilic-hydrophobic conversion materials based on hydrophobic chain regulation is of great significance for the advancement and in-depth understanding of the field of pH-responsive smart superwetting materials. Summary of the Invention

[0006] In view of the problems raised by the prior art, the present invention provides an organic / inorganic hybrid nanoparticle and a hydrophilic-hydrophobic conversion coating that integrates hydrophobic segments and responsive functional groups. It mainly achieves this by integrating hydrophobic segments and pH-responsive functional groups into a molecular design and controlling its pH-responsive behavior and degree of hydrophilic-hydrophobic conversion by regulating the length of the hydrophobic chain. Starting from the molecular structure design, it provides new insights into the balance between hydrophobic chains and pH-responsive hydrophilic-hydrophobic conversion.

[0007] To achieve the above objectives, the present invention employs a technical solution consisting of the following technical measures.

[0008] In one aspect, the present invention provides an organic / inorganic hybrid nanoparticle integrating hydrophobic segments and pH-responsive functional groups, which is an organic / inorganic hybrid nanoparticle composed of inorganic nanoparticles with hydroxyl groups on the surface and organic groups A or B connected by covalent bonds. The proportion of organic groups A or B is characterized by grafting density calculated by thermogravimetric analysis, and the grafting density is 8 to 15 g / g.

[0009] The chemical structural formula of the organic group A is:

[0010]

[0011] In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, R2 is a hydrogen group or a methyl group, and n = 5 to 150;

[0012] The chemical structural formula of the organic group B is:

[0013]

[0014] In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, R2 is a hydrogen group or a methyl group, and n = 5 to 150.

[0015] In the above chemical structural formula, “…” indicates the position where the chemical bond is connected.

[0016] On the other hand, the present invention also provides a method for preparing the above-mentioned organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups. This method involves the condensation reaction of some hydroxyl groups on inorganic nanoparticles with hydroxyl groups on their surface, followed by the formation of siloxane bonds between these hydroxyl groups and organic groups A or B, resulting in organic / inorganic hybrid nanoparticles. It should be noted that those skilled in the art can derive specific preparation steps from the above-described technical content. These steps include directly condensing inorganic nanoparticles with hydroxyl groups on their surface with a compound containing organic group A or organic group B, or modifying inorganic nanoparticles with hydroxyl groups on their surface with a siloxane coupling agent and then polymerizing them with an N-methacrylate monomer having alkyl side chains. Therefore, the technical solutions provided below by the present invention do not imply the sole designation or limitation of the method for preparing the above-described organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups.

[0017] This invention also provides a method for preparing organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0018] (1) N-methylethanolamine is mixed with haloalkanes R1-X, and after tertiary amination substitution reaction, the intermediate N-methylethanolamine with alkyl side chains is prepared by separation and purification; wherein, in the haloalkanes R1-X, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, and X is a halogen atom.

[0019] (2) The N-methylethanol tertiary amine intermediate with alkyl side chain obtained in step (1) is added to solvent A and mixed evenly with acid binding agent and inhibitor. The substitution reaction is carried out by adding acyl halide. After separation and purification, N-methyl acrylate monomer with alkyl side chain is prepared.

[0020] (3) Inorganic nanoparticles with hydroxyl groups on their surface are modified with siloxane coupling agents to prepare inorganic nanoparticles with modified surface double bond function.

[0021] (4) The N-methacrylate monomer with alkyl side chains obtained in step (2) and the inorganic nanoparticles with surface double bond function modified in step (3) are added to solvent A and mixed evenly. An initiator is added and the mixture is reacted at 60-70°C for 12-24 hours in an inert gas atmosphere. After the time is up, the solid product is separated and dried to obtain organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups.

[0022] In this article, in the haloalkane R1-X mentioned in step (1), X is a halogen atom. According to the subsequent tertiary amine substitution reaction, it should be known by those skilled in the art to be selected as a monohaloalkane. The haloalkane commonly used in chemical production can be selected according to common knowledge in the art, such as X being fluorine, chlorine, bromine or iodine.

[0023] In one of the technical solutions, the haloalkane R1-X mentioned in step (1) is selected from any one of the following: propane bromo, n-butane bromo, sec-butane bromo, pentane bromo, n-hexane bromo, 3-bromohexane, heptane bromo, 3-bromoheptane, n-nonane bromo, 2-bromononane, undecane bromo, 5-(bromomethyl)undecane, tridecane bromo, hexadecane bromo, 1-bromo-2-methylhexadecane, octadecane bromo, propane chloro, pentane chloro, hexane chloro, heptane chloro, nonane chloro, undecane chloro, dodecane chloro, and tetradecane chloro.

[0024] In this article, the tertiary amination substitution reaction described in step (1) can be understood by those skilled in the art based on the selection of N-methylethanolamine and haloalkanes R1-X provided by the present invention and the common knowledge of chemical synthesis in the art. The reaction conditions and target products can be referred to the conventional reaction of secondary amines with haloalkanes.

[0025] To better illustrate the present invention and provide a technical solution for reference, the tertiary amination substitution reaction described in step (1) specifically involves adding an alkaline solution after mixing N-methylethanolamine and haloalkane R1-X, and stirring the mixture at a temperature of 40-60°C for 12-24 hours. The alkaline solution is a solution prepared by dissolving a conventional alkaline salt in water, such as a sodium hydroxide solution or sodium carbonate solution with a molar concentration of 1-15 mol / L. The liquid-to-solid ratio of the alkaline solution to N-methylethanolamine is (1-5) ml: 1 g, and the molar ratio of haloalkane R1-X to N-methylethanolamine is (1-1.5): 1.

[0026] In this article, after the tertiary amination substitution reaction described in step (1), it is necessary to separate and purify the N-methylethanol tertiary amine intermediate with alkyl side chains. Those skilled in the art can refer to the conventional separation and purification process of the product after the reaction of secondary amines with haloalkanes, such as extraction (e.g., using dichloromethane or ethyl acetate), washing with water (e.g., using saturated saline solution), drying, filtration and concentration in sequence. The specific steps and operations of the above separation and purification are common knowledge in this technical field and will not be repeated here.

[0027] In this paper, the N-methylethanol tertiary amine intermediate with alkyl side chains prepared in step (1) is shown in the following chemical reaction formula:

[0028]

[0029] In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, and X is a halogen atom.

[0030] In this paper, the substitution reaction described in step (2) is based on the selection of the alkyl-side chain N-methylethanol tertiary amine intermediate and the acyl halide provided by the present invention. According to the common knowledge of chemical synthesis in the field, the substitution reaction is a nucleophilic substitution reaction. The reaction conditions, acid-binding agents, inhibitors and solvents and the target product can all be referred to the conventional reaction of hydroxyl-containing compounds with acyl halides.

[0031] To better illustrate the present invention and provide a technical solution for reference, the acid binding agent in step (2) is selected from any one of triethylamine, pyridine, sodium carbonate, sodium bicarbonate, potassium hydrochloride, sodium hydroxide, potassium hydroxide, and sodium acetate.

[0032] To better illustrate the present invention and provide a technical solution for reference, the inhibitor in step (2) is selected from any one of hydroquinone, butylated hydroxytoluene, or methoxyphenol.

[0033] To better illustrate the present invention and provide a reference technical solution, the solvent A in step (2) is selected from any one of dichloromethane, tetrahydrofuran, diethyl ether, toluene, and ethyl acetate. It should be noted that the solvent A in step (4) can also be selected in accordance with the above. The amount of solvent A added in step (2) can be based on a volume ratio of (2.5–10):1 with the N-methylethanol tertiary amine intermediate having an alkyl side chain.

[0034] In this article, the acyl halide mentioned in step (2) is a compound formed by replacing a hydroxyl group with a halogen atom. The acyl halide can be selected according to common knowledge in the field and is commonly used in chemical production. For example, the halogen atom is fluorine, chlorine, bromine or iodine.

[0035] To better illustrate the present invention and provide a technical solution for reference, the acyl halide in step (2) is selected from any one of methacryloyl chloride, methacryloyl bromide, acryloyl chloride, and acryloyl bromide.

[0036] To better illustrate the present invention and provide a reference technical solution, the molar ratio of the N-methylethanol tertiary amine intermediate with alkyl side chains to the acyl halide, acid binder, and inhibitor in step (2) is 1:(1-2.5):(1-3.5):(0.01-0.05).

[0037] To better illustrate the present invention and provide a technical solution for reference, the substitution reaction of adding acyl halide in step (2) is specifically carried out by adding the acyl halide dropwise under laboratory conditions, followed by stirring the reaction for 12–24 hours. In industrial-scale implementation, those skilled in the art can select appropriate reaction conditions based on the actual situation.

[0038] In this article, after the substitution reaction of adding acyl halide in step (2), it is necessary to separate and purify the N-methacrylate monomer with alkyl side chains. Those skilled in the art can refer to the conventional separation and purification process of the product after the reaction of hydroxyl-containing compounds with acyl halide, such as sequentially performing filtration, concentration, water washing, extraction (e.g. using ethyl acetate or dichloromethane), alkali washing (e.g. using saturated sodium bicarbonate or saturated sodium hydroxide solution), salt washing (e.g. using saturated salt water solution), drying (e.g. adding a desiccant at room temperature), filtration and concentration. The specific steps and operations of the above separation and purification are common knowledge in this technical field and will not be repeated here.

[0039] In this paper, the N-methacrylate monomer with alkyl side chains prepared in step (2) is shown in the following chemical reaction formula:

[0040]

[0041] In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, R2 is a hydrogen group or a methyl group, and R3 is a halogen atom.

[0042] In this article, the modification of inorganic nanoparticles with hydroxyl groups on the surface by a siloxane coupling agent in step (3) is a conventional modification method in the field. The specific modification conditions and operations can be referred to the instructions for use of the siloxane coupling agent or the records in the existing technical literature.

[0043] To obtain a chemical structure conforming to organic groups A and B, the siloxane coupling agent is γ-(methacryloyl chloride)propyltrimethoxysilane (KH570) or vinyltrimethoxysilane (KH171). It should be noted that other siloxane coupling agents can theoretically be used, but whether they can achieve the technical effects proposed in this invention is currently unknown.

[0044] In this paper, the inorganic nanoparticles with hydroxyl groups on their surface mentioned in step (3) are a class of inorganic nanoparticles that have hydroxyl groups mainly due to surface oxidation reactions, such as any one or more of nano-silica, nano-titanium dioxide, nano-zinc dioxide, nano-alumina, nano-magnesium oxide, and nano-iron oxide.

[0045] In one of the technical solutions, the mass ratio of the siloxane coupling agent to the inorganic nanoparticles with hydroxyl groups on the surface in step (3) is (1-10):(1-10).

[0046] To better illustrate the present invention and provide a reference technical solution, the modification of inorganic nanoparticles with hydroxyl groups on their surface by a siloxane coupling agent in step (3) specifically involves dispersing the inorganic nanoparticles with hydroxyl groups on their surface in an organic solvent, adding ammonia and a siloxane coupling agent, and stirring the mixture at a temperature of 12–50°C for 24–48 hours. The ammonia concentration is 25–27%, the ratio of the inorganic nanoparticles with hydroxyl groups to the organic solvent is 1 g:(50–200) ml, and the volume ratio of the organic solvent to ammonia is (5–30):1. It should be noted that the organic solvent used in this technical solution is a conventional organic solvent selected for the chemical industry, such as any one of anhydrous ethanol, n-hexane, cyclohexane, dichloromethane, n-heptane, n-octane, acetone, benzene, toluene, or ethyl acetate.

[0047] In this document, the initiator mentioned in step (4) is an initiator commonly used in polymerization reactions in this technical field. Those skilled in the art can select a suitable initiator according to actual needs.

[0048] To better illustrate the present invention and provide a technical solution for reference, the initiator selected in step (4) includes azobisisobutyronitrile or benzoyl peroxide; the amount of the initiator added is 1% to 5% of the total mass of the N-methacrylate monomer with alkyl side chains and the inorganic nanoparticles with surface double bond functional modification.

[0049] In one technical solution, the mass ratio of the surface double-bond functionalized inorganic nanoparticles to the N-methacrylate monomer with alkyl side chains is (1-20):1. The grafting amount is controlled by adjusting the mass ratio between the surface double-bond functionalized inorganic nanoparticles and the N-methacrylate monomer with alkyl side chains. The higher the monomer feed ratio, the higher the relative content of grafted monomers on the surface of the inorganic nanoparticles, i.e., the higher the grafting density, and the better the hydrophobicity of the resulting product, but the responsiveness will decrease.

[0050] Based on the above findings and comparative experimental results, in order to obtain organic / inorganic hybrid nanoparticles that integrate hydrophobic segments and pH-responsive functional groups with better overall hydrophobicity and responsiveness, in one preferred technical solution, the grafting density is 9-13 g / g, and more preferably 10-12 g / g.

[0051] In this document, the stirring reaction is a stirring reaction conventionally used in the art, including magnetic stirring or mechanical stirring. Those skilled in the art can choose a suitable stirring reaction method according to the production scale or current process conditions. In one technical solution, the stirring reaction can be carried out at a stirring rate of 100-300 rpm.

[0052] On the other hand, based on the above-mentioned organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, the present invention also provides a hydrophobic coating using the above-mentioned organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups as the main component, the raw materials of which mainly include, by weight:

[0053] One portion of organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups.

[0054] Solvent B: 50-150 parts.

[0055] In this document, solvent B is a solvent commonly used in chemical coating products, such as any one or more of anhydrous ethanol, n-hexane, cyclohexane, dichloromethane, n-heptane, n-octane, acetone, benzene, toluene, and ethyl acetate.

[0056] In one preferred embodiment, the hydrophobic coating further comprises, by weight, the following raw materials:

[0057] 1-5 parts of filler

[0058] Additives: 1-5 parts.

[0059] In order to improve the physical strength of the coating film after application, the raw material components include fillers, which are known and commonly used inorganic or organic fillers, preferably one or more of titanium dioxide, bentonite, barium sulfate, spherical silica, nano calcium carbonate, and talc. Further, it is preferred that known and commonly used metal oxides are used as both fillers and pigments.

[0060] The additive is one or more combinations of pigments, heat-resistant polymerization inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants, and rust inhibitors. Typically, the pigments, heat-resistant polymerization inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants, and rust inhibitors mentioned above are commonly known and used.

[0061] It should be noted that the hydrophobic coating provided by this invention follows the conventional coating method for hydrophobic / hydrophilic coatings in the chemical industry. For example, after applying an adhesive to a smooth substrate, the hydrophobic coating is then applied to its surface, and after drying, a hydrophobic coating is obtained.

[0062] Typically, the coating method is one of spraying, brushing, or dipping; the adhesive includes, but is not limited to, 3M adhesive, commonly used coating resin adhesive, inorganic adhesive, etc.; the substrate is any one of textiles, glass, wood, stainless steel mesh, copper mesh, sponge, aluminum, iron, cement board, ceramics, or paper products.

[0063] The hydrophobic coating provided by this invention, based on the selection of raw materials during its preparation process, controls the hydrophobic chain length. When the hydrophobic chain length meets specific conditions (such as Example 1 below), it exhibits the characteristic of hydrophilic-hydrophobic conversion, and can thus be used as a pH-responsive hydrophilic-hydrophobic conversion coating. After it is coated on a substrate to form a pH-responsive hydrophilic-hydrophobic conversion coating, when the surface of the pH-responsive hydrophilic-hydrophobic conversion coating comes into contact with an acidic liquid with a pH of 1 to 5, the pH-responsive hydrophilic-hydrophobic conversion coating changes from hydrophobic to hydrophilic.

[0064] The present invention has the following beneficial effects:

[0065] 1. This invention provides an organic / inorganic hybrid nanoparticle and hydrophilic-hydrophobic conversion coating that integrates hydrophobic segments and responsive functional groups. It mainly achieves this by integrating hydrophobic segments and pH-responsive functional groups into a molecular design and controlling the pH-responsive behavior and the degree of hydrophilic-hydrophobic conversion by regulating the length of the hydrophobic chain. Starting from the molecular structure design, it provides new insights into the balance between hydrophobic chains and pH-responsive hydrophilic-hydrophobic conversion.

[0066] 2. The present invention provides an integrated organic / inorganic hybrid nanoparticle combining hydrophobic segments and pH-responsive functional groups. This design integrates hydrophobic segments and pH-responsive groups into a single molecular structure, allowing for precise control of the responsive groups and wettability through the hydrophobic chain length. Furthermore, this integrated organic / inorganic hybrid nanoparticle features a rough surface structure, a simple and controllable overall manufacturing process, and the ability to adjust the side chain length according to specific requirements.

[0067] 3. The present invention provides an organic / inorganic hybrid nanoparticle integrating hydrophobic segments and pH-responsive functional groups. The raw materials for preparation are readily available and inexpensive, and no complex and expensive equipment is required, and the preparation conditions are mild. Attached Figure Description

[0068] Figure 1 This is a diagram showing the surface morphology and elemental distribution of the pH-responsive hydrophilic-hydrophobic conversion coating obtained in Example 1 of the present invention.

[0069] Figure 2 This is a comparison chart showing the static contact angle of the pH-responsive hydrophilic-hydrophobic conversion coating obtained in Example 1 of the present invention over time for droplets with pH=1 and pH=5, respectively.

[0070] Figure 3This is a graph showing the test results of the adhesion force of the hydrophobic coating surface to water droplets obtained in Example 2 of the present invention.

[0071] Figure 4 This is a comparison chart showing the static contact angle of the hydrophobic coating obtained in Example 3 of the present invention with respect to droplets with pH=1 and pH=5 over time.

[0072] Figure 5 This is a comparison of the thermogravimetric analysis (TGA) curves of the raw material silica particles, intermediate products, and finally prepared organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups of different side chain lengths obtained in Examples 1-3 of this invention. In the figure, SiO2 refers to the raw material silica particles (30 nm) used in Examples 1-3; MPS-SiO2 refers to the nano-silica particles with double bond functional modification on the surface of the intermediate product obtained in step (3) of Example 1; TA-C3 / MPS-SiO2 refers to the organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups of 3 obtained in Example 1; TA-C6 / MPS-SiO2 refers to the organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups of 6 obtained in Example 2; and TA-C9 / MPS-SiO2 refers to the organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups of 9 obtained in Example 3. Detailed Implementation

[0073] To further understand the present invention, preferred embodiments are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims. Those skilled in the art can refer to the content of this document to appropriately improve the process parameters. In particular, it should be noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of the present invention. The methods and applications of the present invention have been described through preferred embodiments, and those skilled in the art can obviously make modifications or appropriate changes and combinations to the methods and applications described herein without departing from the content, spirit and scope of the present invention to realize and apply the technology of the present invention. Although it is believed that those skilled in the art will fully understand the following terms, the following definitions are set forth to help illustrate the subject matter disclosed in the present invention.

[0074] In one aspect, the present invention provides an organic / inorganic hybrid nanoparticle integrating hydrophobic segments and pH-responsive functional groups, which is an organic / inorganic hybrid nanoparticle composed of inorganic nanoparticles with hydroxyl groups on the surface and organic groups A or B connected by covalent bonds. The proportion of organic groups A or B is characterized by grafting density calculated by thermogravimetric analysis, and the grafting density is 8 to 15 g / g.

[0075] The chemical structural formula of the organic group A is:

[0076]

[0077] In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, R2 is a hydrogen group or a methyl group, and n = 5 to 150;

[0078] The chemical structural formula of the organic group B is:

[0079]

[0080] In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, R2 is a hydrogen group or a methyl group, and n = 5 to 150.

[0081] In the above chemical structural formula, “…” indicates the position where the chemical bond is connected.

[0082] On the other hand, the present invention also provides a method for preparing the above-mentioned organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups. This method involves the condensation reaction of some hydroxyl groups on inorganic nanoparticles with hydroxyl groups on their surface, followed by the formation of siloxane bonds between these hydroxyl groups and organic groups A or B, resulting in organic / inorganic hybrid nanoparticles. It should be noted that those skilled in the art can derive specific preparation steps from the above-described technical content. These steps include directly condensing inorganic nanoparticles with hydroxyl groups on their surface with a compound containing organic group A or organic group B, or modifying inorganic nanoparticles with hydroxyl groups on their surface with a siloxane coupling agent and then polymerizing them with an N-methacrylate monomer having alkyl side chains. Therefore, the embodiments provided below do not imply a unique designation or limitation on the method for preparing the organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups.

[0083] This invention also provides a method for preparing organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0084] (1) N-methylethanolamine is mixed with haloalkanes R1-X, and after tertiary amination substitution reaction, the intermediate N-methylethanolamine with alkyl side chains is prepared by separation and purification; wherein, in the haloalkanes R1-X, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, and X is a halogen atom.

[0085] (2) The N-methylethanol tertiary amine intermediate with alkyl side chain obtained in step (1) is added to solvent A and mixed evenly with acid binding agent and inhibitor. The substitution reaction is carried out by adding acyl halide. After separation and purification, N-methyl acrylate monomer with alkyl side chain is prepared.

[0086] (3) Inorganic nanoparticles with hydroxyl groups on their surface are modified with siloxane coupling agents to prepare inorganic nanoparticles with modified surface double bond function.

[0087] (4) The N-methacrylate monomer with alkyl side chains obtained in step (2) and the inorganic nanoparticles with surface double bond function modified in step (3) are added to solvent A and mixed evenly. An initiator is added and the mixture is reacted at 60-70°C for 12-24 hours in an inert gas atmosphere. After the time is up, the solid product is separated and dried to obtain organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups.

[0088] In this article, in the haloalkane R1-X mentioned in step (1), X is a halogen atom. According to the subsequent tertiary amine substitution reaction, it should be known by those skilled in the art to be selected as a monohaloalkane. The haloalkane commonly used in chemical production can be selected according to common knowledge in the art, such as X being fluorine, chlorine, bromine or iodine.

[0089] In one embodiment, the haloalkane R1-X in step (1) is selected from any one of the following: propane bromide, n-butane bromide, sec-butane bromide, pentane bromide, n-hexane bromide, 3-bromohexane, heptane bromide, 3-bromoheptane, n-nonane bromide, 2-bromononane, undecane bromide, 5-(bromomethyl)undecane, tridecane bromide, hexadecane bromide, 1-bromo-2-methylhexadecane, octadecane bromide, propane chlorochloride, pentane chlorochloride, hexane chlorochloride, heptane chlorochloride, nonane chlorochloride, undecane chlorochloride, dodecane chlorochloride, and tetradecane chlorochloride.

[0090] In this article, the tertiary amination substitution reaction described in step (1) can be understood by those skilled in the art based on the selection of N-methylethanolamine and haloalkanes R1-X provided by the present invention and the common knowledge of chemical synthesis in the art. The reaction conditions and target products can be referred to the conventional reaction of secondary amines with haloalkanes.

[0091] To better illustrate the present invention and provide a reference embodiment, the tertiary amination substitution reaction described in step (1) specifically involves adding an alkaline solution after mixing N-methylethanolamine and haloalkane R1-X, and stirring the mixture at a temperature of 40-60°C for 12-24 hours. The alkaline solution is a solution prepared by dissolving a conventional alkaline salt in water, such as a sodium hydroxide solution or sodium carbonate solution with a molar concentration of 1-15 mol / L. The liquid-to-solid ratio of the alkaline solution to N-methylethanolamine is (1-5) ml: 1 g, and the molar ratio of haloalkane R1-X to N-methylethanolamine is (1-1.5): 1.

[0092] In this article, after the tertiary amination substitution reaction described in step (1), it is necessary to separate and purify the N-methylethanol tertiary amine intermediate with alkyl side chains. Those skilled in the art can refer to the conventional separation and purification process of the product after the reaction of secondary amines with haloalkanes, such as extraction (e.g., using dichloromethane or ethyl acetate), washing with water (e.g., using saturated saline solution), drying, filtration and concentration in sequence. The specific steps and operations of the above separation and purification are common knowledge in this technical field and will not be repeated here.

[0093] In this paper, the N-methylethanol tertiary amine intermediate with alkyl side chains prepared in step (1) is shown in the following chemical reaction formula:

[0094]

[0095] In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, and X is a halogen atom.

[0096] In this paper, the substitution reaction described in step (2) is based on the selection of the alkyl-side chain N-methylethanol tertiary amine intermediate and the acyl halide provided by the present invention. According to the common knowledge of chemical synthesis in the field, the substitution reaction is a nucleophilic substitution reaction. The reaction conditions, acid-binding agents, inhibitors and solvents and the target product can all be referred to the conventional reaction of hydroxyl-containing compounds with acyl halides.

[0097] To better illustrate the present invention and to provide a reference embodiment, the acid-binding agent in step (2) is selected from any one of triethylamine, pyridine, sodium carbonate, sodium bicarbonate, potassium hydrochloride, sodium hydroxide, potassium hydroxide, and sodium acetate.

[0098] To better illustrate the present invention and to provide an embodiment for reference, the inhibitor in step (2) is selected from any one of hydroquinone, butylated hydroxytoluene, or methoxyphenol.

[0099] To better illustrate the present invention and provide a reference embodiment, solvent A in step (2) is selected from any one of dichloromethane, tetrahydrofuran, diethyl ether, toluene, and ethyl acetate. It should be noted that solvent A in step (4) can also be selected in accordance with the above. The amount of solvent A added in step (2) can be based on a volume ratio of (2.5–10):1 to the N-methylethanol tertiary amine intermediate having an alkyl side chain.

[0100] In this article, the acyl halide mentioned in step (2) is a compound formed by replacing a hydroxyl group with a halogen atom. The acyl halide can be selected according to common knowledge in the field and is commonly used in chemical production. For example, the halogen atom is fluorine, chlorine, bromine or iodine.

[0101] To better illustrate the present invention and to provide an embodiment for reference, the acyl halide in step (2) is selected from any one of methacryloyl chloride, methacryloyl bromide, acryloyl chloride, and acryloyl bromide.

[0102] To better illustrate the present invention and to provide an embodiment for reference, the molar ratio of the N-methylethanol tertiary amine intermediate with alkyl side chains to the acyl halide, acid binder, and inhibitor in step (2) is 1:(1-2.5):(1-3.5):(0.01-0.05).

[0103] To better illustrate the present invention and provide a reference embodiment, the substitution reaction described in step (2) involves adding the acyl halide dropwise under laboratory conditions, followed by stirring the reaction for 12–24 hours. In industrial-scale implementation, those skilled in the art can select appropriate reaction conditions based on actual circumstances.

[0104] In this article, after the substitution reaction of adding acyl halide in step (2), it is necessary to separate and purify the N-methacrylate monomer with alkyl side chains. Those skilled in the art can refer to the conventional separation and purification process of the product after the reaction of hydroxyl-containing compounds with acyl halide, such as sequentially performing filtration, concentration, water washing, extraction (e.g. using ethyl acetate or dichloromethane), alkali washing (e.g. using saturated sodium bicarbonate or saturated sodium hydroxide solution), salt washing (e.g. using saturated salt water solution), drying (e.g. adding a desiccant at room temperature), filtration and concentration. The specific steps and operations of the above separation and purification are common knowledge in this technical field and will not be repeated here.

[0105] In this paper, the N-methacrylate monomer with alkyl side chains prepared in step (2) is shown in the following chemical reaction formula:

[0106]

[0107] In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, R2 is a hydrogen group or a methyl group, and R3 is a halogen atom.

[0108] In this article, the modification of inorganic nanoparticles with hydroxyl groups on the surface by a siloxane coupling agent in step (3) is a conventional modification method in the field. The specific modification conditions and operations can be referred to the instructions for use of the siloxane coupling agent or the records in the existing technical literature.

[0109] To obtain a chemical structure conforming to organic groups A and B, the siloxane coupling agent is γ-(methacryloyl chloride)propyltrimethoxysilane (KH570) or vinyltrimethoxysilane (KH171). It should be noted that other siloxane coupling agents can theoretically be used, but whether they can achieve the technical effects proposed in this invention is currently unknown.

[0110] In this paper, the inorganic nanoparticles with hydroxyl groups on their surface mentioned in step (3) are a class of inorganic nanoparticles that have hydroxyl groups mainly due to surface oxidation reactions, such as any one or more of nano-silica, nano-titanium dioxide, nano-zinc dioxide, nano-alumina, nano-magnesium oxide, and nano-iron oxide.

[0111] In one embodiment, the mass ratio of the siloxane coupling agent to the inorganic nanoparticles with hydroxyl groups on the surface in step (3) is (1-10):(1-10).

[0112] To better illustrate the present invention and provide a reference embodiment, the modification of inorganic nanoparticles with hydroxyl groups on their surface by a siloxane coupling agent in step (3) specifically involves dispersing the inorganic nanoparticles with hydroxyl groups on their surface in an organic solvent, adding ammonia and a siloxane coupling agent, and stirring the mixture at a temperature of 12–50°C for 24–48 hours. The ammonia concentration is 25–27%, the ratio of the inorganic nanoparticles with hydroxyl groups to the organic solvent is 1 g:(50–200) ml, and the volume ratio of the organic solvent to ammonia is (5–30):1. It should be noted that the organic solvent used in this embodiment is a conventional organic solvent selected for the chemical industry, such as any one of anhydrous ethanol, n-hexane, cyclohexane, dichloromethane, n-heptane, n-octane, acetone, benzene, toluene, and ethyl acetate.

[0113] In this document, the initiator mentioned in step (4) is an initiator commonly used in polymerization reactions in this technical field. Those skilled in the art can select a suitable initiator according to actual needs.

[0114] To better illustrate the present invention and to provide an embodiment for reference, the initiator selected in step (4) includes azobisisobutyronitrile or benzoyl peroxide; the amount of the initiator added is 1% to 5% of the total mass of the N-methacrylate monomer with alkyl side chains and the inorganic nanoparticles with surface double bond functional modification.

[0115] In one embodiment, the mass ratio of the surface-double-bond functionalized inorganic nanoparticles to the N-methacrylate monomer with alkyl side chains is (1-20):1. The grafting amount is controlled by adjusting the mass ratio between the surface-double-bond functionalized inorganic nanoparticles and the N-methacrylate monomer with alkyl side chains. A higher monomer feed ratio results in a higher relative content of grafted monomers on the surface of the inorganic nanoparticles, i.e., a higher grafting density, which leads to better hydrophobicity of the resulting product, but reduces responsiveness.

[0116] Based on the above findings and comparative experimental results, in order to obtain organic / inorganic hybrid nanoparticles that integrate hydrophobic segments and pH-responsive functional groups with better overall hydrophobicity and responsiveness, in one preferred embodiment, the grafting density is 9-13 g / g, and more preferably 10-12 g / g.

[0117] In this document, the stirring reaction is a stirring reaction conventionally used in the art, including magnetic stirring or mechanical stirring. Those skilled in the art can choose a suitable stirring reaction method according to the production scale or current process conditions. In one embodiment, the stirring reaction can be carried out at a stirring rate of 100–300 rpm.

[0118] On the other hand, based on the above-mentioned organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, the present invention also provides a hydrophobic coating using the above-mentioned organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups as the main component, the raw materials of which mainly include, by weight:

[0119] One portion of organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups.

[0120] Solvent B: 50-150 parts.

[0121] In this document, solvent B is a solvent commonly used in chemical coating products, such as any one or more of anhydrous ethanol, n-hexane, cyclohexane, dichloromethane, n-heptane, n-octane, acetone, benzene, toluene, and ethyl acetate.

[0122] In one preferred embodiment, the hydrophobic coating further comprises, by weight, the following raw materials:

[0123] 1-5 parts of filler

[0124] Additives: 1-5 parts.

[0125] In order to improve the physical strength of the coating film after application, the raw material components include fillers, which are known and commonly used inorganic or organic fillers, preferably one or more of titanium dioxide, bentonite, barium sulfate, spherical silica, nano calcium carbonate, and talc. Further, it is preferred that known and commonly used metal oxides are used as both fillers and pigments.

[0126] The additive is one or more combinations of pigments, heat-resistant polymerization inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants, and rust inhibitors. Typically, the pigments, heat-resistant polymerization inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants, and rust inhibitors mentioned above are commonly known and used.

[0127] It should be noted that the hydrophobic coating provided by this invention follows the conventional coating method for hydrophobic / hydrophilic coatings in the chemical industry. For example, after applying an adhesive to a smooth substrate, the hydrophobic coating is then applied to its surface, and after drying, a hydrophobic coating is obtained.

[0128] Typically, the coating method is one of spraying, brushing, or dipping; the adhesive includes, but is not limited to, 3M adhesive, commonly used coating resin adhesive, inorganic adhesive, etc.; the substrate is any one of textiles, glass, wood, stainless steel mesh, copper mesh, sponge, aluminum, iron, cement board, ceramics, or paper products.

[0129] The hydrophobic coating provided by this invention, based on the selection of raw materials during its preparation process, controls the hydrophobic chain length. When the hydrophobic chain length meets specific conditions (such as Example 1 below), it exhibits the characteristic of hydrophilic-hydrophobic conversion, and can thus be used as a pH-responsive hydrophilic-hydrophobic conversion coating. After it is coated on a substrate to form a pH-responsive hydrophilic-hydrophobic conversion coating, when the surface of the pH-responsive hydrophilic-hydrophobic conversion coating comes into contact with an acidic liquid with a pH of 1 to 5, the pH-responsive hydrophilic-hydrophobic conversion coating changes from hydrophobic to hydrophilic.

[0130] The present application will be further explained in detail below with reference to embodiments. However, those skilled in the art should understand that these embodiments are provided for illustrative purposes only and are not intended to limit the present application.

[0131] Example

[0132] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of this application. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all commercially available conventional products. This application should not be construed as being limited to the specific embodiments described.

[0133] 1. Raw materials

[0134] N-methylethanolamine, propane bromide, n-hexane bromide, n-nonane bromide, methacryloyl chloride, γ-(methacryloyl chloride)propyltrimethoxysilane, and nano-silica were provided by Shanghai Aladdin Reagent Co., Ltd.

[0135] Azobisisobutyronitrile, hydroquinone, ethyl acetate, dichloromethane, tetrahydrofuran, ammonia, sodium chloride, sodium bicarbonate, sodium hydroxide, and anhydrous sodium carbonate were supplied by Chengdu Kelong Chemical Co., Ltd.

[0136] 2. Testing Methods

[0137] (1) The microstructure and elemental distribution of the coating surface were observed by scanning electron microscopy (SEM / EDX, Phenom ProX, Netherlands).

[0138] (2) The wetting performance of the coating surface was tested using a contact angle tester (Zhongchen Digital Equipment Co. Ltd., Shanghai, China).

[0139] (3) The thermogravimetric analysis curves of the samples were tested using a thermogravimetric analyzer (TG 209F1 instrument, NETZSCH, Germany), and the grafting density was calculated based on this. Specifically, it was calculated by dividing the mass loss of organic / inorganic hybrid nanoparticles by the mass loss of pure inorganic nanoparticles at 700℃ by the residual mass of organic / inorganic hybrid nanoparticles. The mass loss of pure inorganic nanoparticles was obtained by thermogravimetric analysis of the same mass as organic / inorganic hybrid nanoparticles as a control group.

[0140] Example 1

[0141] This embodiment describes a method for preparing organic / inorganic hybrid nanoparticles that integrate hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0142] (1) Preparation of N-methylethanol tertiary amine intermediate with alkyl side chain length of 3: 15.1347 g (0.20 mol) of N-methylethanolamine was mixed with 27.0625 g (0.22 mol) of bromopropane, 30 mL of 10 mol / L sodium hydroxide solution was added, and the mixture was stirred at 40 °C for 12 h. After the reaction, the mixture was extracted with dichloromethane, washed with saturated brine, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain N-methylethanol tertiary amine intermediate with alkyl side chain length of 3.

[0143] (2) Preparation of N-methacrylate monomer with alkyl side chain length of 3: 11.7958 g (0.10 mol) of N-methylethanol tertiary amine intermediate with alkyl side chain length of 3, 15.1785 g (0.15 mol) of triethylamine, and 0.1123 g (0.001 mol) of hydroquinone were mixed in 100 mL of tetrahydrofuran. 11.5024 g (0.11 mol) of methacryloyl chloride was added dropwise under an ice-water bath. The mixture was stirred at room temperature for 12 h. After the reaction, the mixture was filtered, concentrated, washed with water, extracted with ethyl acetate, washed with saturated sodium bicarbonate alkali, washed with saturated brine, dried, filtered, and concentrated to obtain N-methacrylate monomer with alkyl side chain length of 3.

[0144] (3) Preparation of inorganic nanoparticles with surface double bond function modification: 2g of silica particles (30nm) were dispersed in 200mL of ethanol and reacted with 4.4837g of γ-(methacryloyl chloride)propyltrimethoxysilane at room temperature for 24h under the catalysis of 10mL of ammonia water with a mass fraction of 25% to obtain silica nanoparticles with surface double bond function modification.

[0145] (4) Preparation of organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups with a side chain length of 3: 0.1 g of surface double bond modified silica nanoparticles, 0.05 g of N-methacrylate monomer with an alkyl side chain length of 3 and 0.0020 g of azobisisobutyronitrile were added to 50 mL of tetrahydrofuran solvent. After purging nitrogen gas into a three-necked flask for 5 minutes, the reaction was carried out at 65 °C for 12 h. After washing with tetrahydrofuran and anhydrous ethanol respectively, centrifuging, and drying at 80 °C, organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups with a side chain length of 3 were obtained.

[0146] To facilitate testing, a pH-responsive hydrophilic-hydrophobic conversion coating was prepared based on organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups integrated with the obtained side chain length of 3. 0.1 g of organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups integrated with the obtained side chain length of 3 were dispersed in 10 mL of anhydrous ethanol. A layer of 3M adhesive was applied to a glass substrate using a spraying method, and then the coating was sprayed onto the surface to obtain a pH-responsive hydrophilic-hydrophobic conversion coating with an alkyl hydrophobic chain length of 3, which was used as a sample.

[0147] The morphology and elemental distribution of the organic / inorganic hybrid nanoparticles with a side chain length of 3 and pH-responsive functional groups obtained in this example are as follows: Figure 1 As shown, the coating exhibits pH-responsive wetting behavior for droplets with pH=1, such as... Figure 2 As shown.

[0148] Example 2

[0149] This embodiment describes a method for preparing organic / inorganic hybrid nanoparticles that integrate hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0150] (1) Preparation of N-methylethanol tertiary amine intermediate with alkyl side chain length of 6: 15.0256 g (0.20 mol) of N-methylethanolamine was mixed with 36.3248 g (0.22 mol) of n-hexane bromide, 30 mL of 10 mol / L sodium hydroxide solution was added, and the mixture was stirred at 40 °C for 12 h. After the reaction, the mixture was extracted with dichloromethane, washed with saturated brine, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain N-methylethanol tertiary amine intermediate with alkyl side chain length of 6.

[0151] (2) Preparation of N-methacrylate monomer with alkyl side chain length of 6: 16.0281 g (0.10 mol) of N-methylethanol tertiary amine intermediate with alkyl side chain length of 6, 15.6832 g (0.15 mol) of triethylamine, and 0.1543 g (0.001 mol) of hydroquinone were mixed in 100 mL of tetrahydrofuran. 11.7156 g (0.11 mol) of methacryloyl chloride was added dropwise under an ice-water bath. The mixture was stirred at room temperature for 12 h. After the reaction, the mixture was filtered, concentrated, washed with water, extracted with ethyl acetate, washed with saturated sodium bicarbonate, washed with saturated brine, dried, filtered, and concentrated to obtain N-methacrylate monomer with alkyl side chain length of 6.

[0152] (3) Preparation of inorganic nanoparticles with surface double bond function modification: 1g of silica particles (30nm) were dispersed in 100mL of ethanol and reacted with 2.4835g of γ-(methacryloyl chloride)propyltrimethoxysilane at room temperature for 24h under the catalysis of 10mL of ammonia water with a mass fraction of 25% to obtain silica nanoparticles with surface double bond function modification.

[0153] (4) Preparation of organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups with a side chain length of 6: 0.2 g of surface double bond modified silica nanoparticles, 0.1 g of N-methacrylate monomer with an alkyl side chain length of 6 and 0.015 g of azobisisobutyronitrile were added to 80 mL of tetrahydrofuran solvent. After purging nitrogen gas into a three-necked flask for 10 minutes, the reaction was carried out at 65 °C for 12 h. After washing with tetrahydrofuran and anhydrous ethanol respectively, centrifuging, and drying at 80 °C, organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups with a side chain length of 6 were obtained.

[0154] To facilitate testing, a hydrophobic coating was prepared based on organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups integrated with the obtained side chain length of 6: 0.15 g of organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups integrated with the obtained side chain length of 6 were dispersed in 10 mL of anhydrous ethanol. After applying a layer of 3M adhesive to a glass substrate by spraying, the coating was then sprayed onto the surface to obtain a hydrophobic coating with an alkyl hydrophobic chain length controlled by 6, which was used as a sample.

[0155] The hydrophobic coating surface obtained in this example exhibits an adhesion force of 40 μN to water droplets. Figure 3 As shown.

[0156] Example 3

[0157] This embodiment describes a method for preparing organic / inorganic hybrid nanoparticles that integrate hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0158] (1) Preparation of N-methylethanol tertiary amine intermediate with alkyl side chain length of 9: 15.1092 g (0.20 mol) of N-methylethanolamine was mixed with 51.5773 g (0.25 mol) of n-bromononane, 30 mL of 10 mol / L sodium hydroxide solution was added, and the mixture was stirred at 40 °C for 12 h. After the reaction, the mixture was extracted with dichloromethane, washed with saturated brine, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain N-methylethanol tertiary amine intermediate with alkyl side chain length of 9.

[0159] (2) Preparation of N-methacrylate monomer with alkyl side chain length of 9: 26.1538 g (0.13 mol) of N-methylethanol tertiary amine intermediate with alkyl side chain length of 9, 18.5612 g (0.18 mol) of triethylamine, and 0.2510 g (0.002 mol) of hydroquinone were mixed in 150 mL of tetrahydrofuran. 16.4236 g (0.16 mol) of methacryloyl chloride was added dropwise under an ice-water bath. The mixture was stirred at room temperature for 12 h. After the reaction, the mixture was filtered, concentrated, washed with water, extracted with ethyl acetate, washed with saturated sodium bicarbonate, washed with saturated brine, dried, filtered, and concentrated to obtain N-methacrylate monomer with alkyl side chain length of 9.

[0160] (3) Preparation of inorganic nanoparticles with surface double bond function modification: 1.5g of silica particles (30nm) were dispersed in 150mL of ethanol and reacted with 2.5043g of γ-(methacryloyl chloride)propyltrimethoxysilane at room temperature for 24h under the catalysis of 20mL of ammonia water with a mass fraction of 25% to obtain silica nanoparticles with surface double bond function modification.

[0161] (4) Preparation of organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups with a side chain length of 9: 0.25 g of surface double bond modified silica nanoparticles, 0.25 g of N-methacrylate monomer with an alkyl side chain length of 9 and 0.0244 g of azobisisobutyronitrile were added to 50 mL of tetrahydrofuran solvent. After purging nitrogen gas into a three-necked flask for 10 minutes, the reaction was carried out at 65 °C for 12 h. After washing with tetrahydrofuran and anhydrous ethanol respectively, centrifuging, and drying at 80 °C, organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups with a side chain length of 9 were obtained.

[0162] To facilitate testing, a hydrophobic coating was prepared based on the obtained organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups integrated with hydrophobic segments with a side chain length of 9: 0.15 g of organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups integrated with hydrophobic segments with a side chain length of 9 were dispersed in 20 mL of anhydrous ethanol. After applying a layer of 3M adhesive to a glass substrate by spraying, the coating was then sprayed onto the surface to obtain a hydrophobic coating with an alkyl hydrophobic chain length controlled by 3, which was used as a sample.

[0163] The hydrophobic coating obtained in this example does not exhibit pH-responsive wetting behavior for droplets with pH=1, such as Figure 4 As shown.

[0164] Example 4

[0165] This embodiment describes a method for preparing organic / inorganic hybrid nanoparticles that integrate hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0166] (1) Preparation of N-methylethanol tertiary amine intermediate with alkyl side chain length of 6: 15.6194 g (0.21 mol) of N-methylethanolamine was mixed with 45.5109 g (0.28 mol) of n-hexane bromide, 50 mL of 10 mol / L sodium hydroxide solution was added, and the mixture was stirred at 40 °C for 12 h. After the reaction, the mixture was extracted with dichloromethane, washed with saturated brine, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain N-methylethanol tertiary amine intermediate with alkyl side chain length of 6.

[0167] (2) Preparation of N-methacrylate monomer with alkyl side chain length of 6: 17.5891 g (0.11 mol) of N-methylethanol tertiary amine intermediate with alkyl side chain length of 6, 15.2653 g (0.15 mol) of triethylamine, and 0.1883 g (0.002 mol) of hydroquinone were mixed in 120 mL of tetrahydrofuran. 15.5456 g (0.15 mol) of methacryloyl chloride was added dropwise under an ice-water bath. The mixture was stirred at room temperature for 12 h. After the reaction, the mixture was filtered, concentrated, washed with water, extracted with ethyl acetate, washed with saturated sodium bicarbonate, washed with saturated brine, dried, filtered, and concentrated to obtain N-methacrylate monomer with alkyl side chain length of 6.

[0168] (3) Preparation of inorganic nanoparticles with surface double bond function modification: 1.2 g of silica particles (30 nm) were dispersed in 150 mL of ethanol and reacted with 2.2436 g of vinyltrimethoxysilane at room temperature for 24 h under the catalysis of 10 mL of ammonia water with a mass fraction of 25% to obtain silica nanoparticles with surface double bond function modification.

[0169] (4) Preparation of modified pH-responsive organic / inorganic hybrid nanoparticles with a side chain length of 6: 0.2 g of surface double bond functionalized nano-silica particles, 0.2 g of N-methacrylate monomer with an alkyl side chain length of 6 and 0.012 g of azobisisobutyronitrile were added to 100 mL of tetrahydrofuran solvent. After purging nitrogen gas into a three-necked flask for 10 minutes, the reaction was carried out at 65 °C for 12 h. After washing with tetrahydrofuran and anhydrous ethanol respectively, centrifuging, and drying at 80 °C, organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups with a side chain length of 6 were obtained.

[0170] Thermogravimetric analysis was performed on the hydrophobic segments with different side chain lengths and pH-responsive functional groups integrated organic / inorganic hybrid nanoparticles prepared in Examples 1-3, respectively. Figure 5 As shown in Table 1 below, the grafting density was calculated.

[0171] Table 1 shows the mass loss and residual mass information related to the thermogravimetric curves, and the grafting density was calculated.

[0172]

[0173] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A hybrid organic / inorganic nanoparticle integrating hydrophobic segments and pH-responsive functional groups, characterized in that... It is an organic / inorganic hybrid nanoparticle consisting of inorganic nanoparticles with hydroxyl groups on the surface and organic groups A or B connected by covalent bonds. The proportion of organic groups A or B is characterized by the grafting density calculated by thermogravimetric analysis, and the grafting density is 8~15 g / g. The chemical structural formula of the organic group A is: ， In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, R2 is a hydrogen group or a methyl group, and n = 5 to 150; The chemical structural formula of the organic group B is: ， In the formula, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, R2 is a hydrogen group or a methyl group, and n = 5 to 150.

2. A method for preparing organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, characterized in that... Includes the following steps: (1) N-methylethanolamine is mixed with haloalkanes R1-X, and after tertiary amination substitution reaction, the intermediate of N-methylethanolamine with alkyl side chains is prepared by separation and purification; wherein, in the haloalkanes R1-X, R1 is a straight-chain alkyl group with 1 to 18 carbon atoms or containing branches, and X is a halogen atom. (2) The N-methylethanol tertiary amine intermediate with alkyl side chain obtained in step (1) is added to solvent A and mixed evenly with acid binding agent and inhibitor. The substitution reaction is carried out by adding acyl halide. After separation and purification, N-methyl acrylate monomer with alkyl side chain is prepared. (3) Inorganic nanoparticles with hydroxyl groups on the surface are modified with siloxane coupling agents to prepare inorganic nanoparticles with surface double bond function modification. (4) The N-methacrylate monomer with alkyl side chain obtained in step (2) and the inorganic nanoparticles with surface double bond function modified in step (3) are added to solvent A and mixed evenly. An initiator is added and the mixture is reacted at 60~70℃ for 12~24 hours in an inert gas atmosphere. After the time is up, the solid product is separated and dried to obtain the organic / inorganic hybrid nanoparticles with hydrophobic segments and pH-responsive functional groups. Solvent A includes any one of dichloromethane, tetrahydrofuran, diethyl ether, toluene, and ethyl acetate.

3. The preparation method according to claim 2, characterized in that: The haloalkane R1-X mentioned in step (1) includes any one of the following: propane bromide, n-butane bromide, sec-butane bromide, pentane bromide, n-hexane bromide, 3-bromohexane, heptane bromide, 3-bromoheptane, n-nonane bromide, 2-bromononane, undecane bromide, 5-(bromomethyl)undecane, tridecane bromide, hexadecane bromide, 1-bromo-2-methylhexadecane, octadecane bromide, propane chlorochloride, pentane chlorochloride, hexane chlorochloride, n-nonane chlorochloride, undecane chlorochloride, dodecane chlorochloride, and tetradecane chlorochloride.

4. The preparation method according to claim 2, characterized in that: The tertiary amination substitution reaction described in step (1) specifically involves adding an alkaline solution after mixing N-methylethanolamine with haloalkanes R1-X, and stirring the mixture at a temperature of 40-60°C for 12-24 hours.

5. The preparation method according to claim 2, characterized in that: The acid-binding agent mentioned in step (2) includes any one of triethylamine, pyridine, sodium carbonate, sodium bicarbonate, potassium hydrochloride, sodium hydroxide, potassium hydroxide, and sodium acetate; The inhibitor mentioned in step (2) includes any one of hydroquinone, butylated hydroxytoluene, or methoxyphenol; Solvent A in step (2) includes any one of dichloromethane, tetrahydrofuran, diethyl ether, toluene, and ethyl acetate.

6. The preparation method according to claim 2, characterized in that: The acyl halide selected in step (2) includes any one of methacryloyl chloride, methacryloyl bromide, acryloyl chloride, and acryloyl bromide.

7. The preparation method according to claim 2, characterized in that: The siloxane coupling agent mentioned in step (3) is γ-(methacryloyl chloride)propyltrimethoxysilane or vinyltrimethoxysilane.

8. The preparation method according to claim 2, characterized in that: The inorganic nanoparticles with hydroxyl groups on their surface mentioned in step (3) include any one or more of nano-silica, nano-titanium dioxide, nano-zinc dioxide, nano-alumina, nano-magnesium oxide, and nano-iron oxide.

9. The preparation method according to claim 2, characterized in that: In step (3), the inorganic nanoparticles with hydroxyl groups on their surface are modified with a siloxane coupling agent. Specifically, the inorganic nanoparticles with hydroxyl groups on their surface are dispersed in an organic solvent, and ammonia and a siloxane coupling agent are added. The mixture is stirred and reacted at a temperature of 12-50°C for 24-48 hours. The mass concentration of ammonia is 25-27%, the ratio of inorganic nanoparticles with hydroxyl groups on their surface to organic solvent is 1g:(50-200)ml, and the volume ratio of organic solvent to ammonia is (5-30):

1.

10. A hydrophobic coating using organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups as described in claim 1 as the main component, characterized in that... Its main raw materials, by weight, include: One portion of organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups. Solvent B: 50-150 parts; Solvent B includes any one or more of the following: anhydrous ethanol, n-hexane, cyclohexane, dichloromethane, n-heptane, n-octane, acetone, benzene, toluene, and ethyl acetate.

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