Hydrophobic chain segment and response functional group integrated organic / inorganic hybrid nanoparticle and hydrophilic-hydrophobic conversion coating

Abstract

The invention provides a hydrophobic chain segment and response functional group integrated organic / inorganic hybrid nanoparticle and a hydrophilic-hydrophobic conversion coating. The integrated organic / inorganic hybrid nanoparticle is formed by connecting an inorganic nanoparticle with hydroxyl on the surface and an organic group A or an organic group B through a covalent bond, wherein the proportion of the organic group A or the organic group B is represented by grafting density calculated by thermogravimetric analysis, and the grafting density is 8-15g / g. According to the invention, a hydrophobic chain segment and a pH response functional group are subjected to integrated molecular design, and the length of the hydrophobic chain is regulated to control the pH response behavior and the hydrophilic-hydrophobic conversion degree of the hydrophobic chain, so that a new insight is provided for the balance between the hydrophobic chain and the pH response hydrophilic-hydrophobic conversion from the molecular structure design.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent superwetting materials, and relates to an organic / inorganic hybrid nanoparticle integrating a hydrophobic segment and a responsive functional group and a hydrophilic-hydrophobic conversion coating, and specifically relates to an organic / inorganic hybrid nanoparticle integrating a hydrophobic segment and a responsive functional group and a preparation method thereof, and a hydrophobic coating based on alkyl hydrophobic chain length regulation prepared by using the organic / inorganic hybrid nanoparticle integrating a hydrophobic segment and a responsive functional group and an application method of the coating. Background Art

[0002] Wettability is a basic property of a solid surface that repels or attracts liquids when in contact with them. More and more research in industry and academia is devoted to simulating the wettability of extreme natural surfaces. Among them, 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 anticorrosive. Superhydrophobic surfaces refer to surfaces with a water contact angle greater than 150° and a rolling angle less than 10°, usually constructed by low surface energy materials and surface micro / nano hierarchical structures. However, traditionally prepared superhydrophobic surfaces usually have fixed surface wettability due to fixed microstructures and chemical compositions, which cannot meet the actual application environment requirements well. Therefore, so far, smart wetting materials that alternately exert surface properties through external stimuli have attracted more and more attention from researchers. This smart material with reversible wettability, especially the transition between superwetting and superantiwetting, is of great significance in industrial application scenarios such as microfluidic devices, liquid manipulation, and oil-water separation.

[0003] Stimulus-responsive superhydrophobic materials are mainly composed of three parts: low surface energy materials, surface micro / nano rough structures, and stimulus response factors. Micro / nano graded rough structures and low surface energy materials are necessary conditions for the formation of superhydrophobicity, while the response factor will produce a surface response under the action of external stimuli. At present, common external stimuli include magnetism, temperature, light, pH, etc. When external stimuli act, the surface composition changes under the action of the response factor, thereby achieving wettability switching. As a common external stimulus, pH response is easy to operate and implement. By simply changing the pH value of the material, the molecular structure morphology and charge can be changed, thereby achieving a simpler and more convenient conversion of macroscopic wettability.

[0004] The Chinese patent with publication number CN110734655A discloses a pH-responsive super-hydrophobic coating material and a preparation method and application thereof. The coating material is obtained by reacting a stearic acid / nano-titanium dioxide complex with chitosan. The material can change from a super-hydrophobic state to a super-hydrophilic state when the pH is alkaline, and exhibits super-hydrophobic properties when the pH is neutral and acidic. The Chinese patent with publication number CN110642977B discloses the preparation and application of a pH-responsive hydrophobic-oleophobic-hydrophilic-oleophobic reversible transition material. The material is formed by polymerizing a pH-responsive composition on the surface of a substrate, wherein the pH-responsive composition includes a pH-responsive monomer, a fluoroalkyl monomer, a cross-linking agent, and a photoinitiator. This hydrophobic-oleophobic material provides a substrate pH response function by the pH responsive polymer segment therein. After acidic treatment, the amino or pyridine group in the pH responsive monomer is protonated, the hydrophilicity is enhanced, and the material is transformed from hydrophobic-oleophobic to hydrophilic-oleophobic; and after being treated with alkaline substances, the pH responsive monomer is deprotonated, and the material is transformed from hydrophilic-oleophobic to hydrophobic-oleophobic, thereby realizing the reversible transformation of hydrophobic-oleophobic-hydrophilic-oleophobic controlled by pH. The Chinese patent with publication number CN112981973A discloses a method for preparing a pH responsive super-hydrophobic material, which first prepares super-hydrophobic silica, and then mixes it evenly with the acrylate copolymer prepared in the same manner and sprays it on the surface of the fabric to obtain a super-hydrophobic material with pH response. On the basis of the super-hydrophobic material, the material introduces a pH responsive acrylate copolymer component to achieve wettability conversion within a certain pH range.

[0005] The pH-responsive methods and materials disclosed in the above patents all have good wettability conversion performance and pH responsiveness, but the development focus of these disclosed materials or methods is on their pH responsiveness, wettability switchability and application. Their structure is to combine pH-responsive molecules and hydrophobic molecules as two different substances. The control of wettability reversible conversion behavior is limited by the competition and synergy between the response structure and the hydrophobic molecules. The protonated response structure is easily masked by the migrated hydrophobic segments, resulting in poor response effect or poor sustainability. There is no further analysis of how the hydrophobic segments affect pH responsiveness and hydrophilic-hydrophobic conversion from the molecular structure level. Therefore, the development of 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 intelligent superwetting materials. Summary of the invention

[0006] In view of the problems raised by the above-mentioned prior art, the present invention provides an organic / inorganic hybrid nanoparticle with integrated hydrophobic segments and responsive functional groups and a hydrophilic-hydrophobic conversion coating. The invention mainly designs a molecule integrating the hydrophobic segments and the pH responsive functional groups, and controls the pH response behavior and the degree of hydrophilic-hydrophobic conversion by regulating the length of the hydrophobic chain. Starting from the molecular structure design, the invention provides new insights into the balance between the hydrophobic chain and the pH responsive hydrophilic-hydrophobic conversion.

[0007] To achieve the above objectives, the present invention is implemented by adopting a technical solution consisting of the following technical measures.

[0008] In one aspect, the present invention provides an organic / inorganic hybrid nanoparticle with an integrated hydrophobic segment and a pH-responsive functional group, which is an organic / inorganic hybrid nanoparticle connected by a covalent bond between an inorganic nanoparticle having a hydroxyl group on the surface and an organic group A or an organic group B, wherein the proportion of the organic group A or the organic group B is characterized by a 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, R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, R 2 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, R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, R 2 It is a hydrogen group or a methyl group, and n=5-150.

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

[0016] On the other hand, the present invention also provides a method for preparing the above-mentioned organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups, which is to form organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups by condensing some of the hydroxyl groups on the surface of the inorganic nanoparticles with hydroxyl groups and then forming silicon-oxygen bonds with the organic group A or the organic group B, so as to obtain the organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups. It should be noted that those skilled in the art can obtain specific preparation steps based on the above-mentioned technical content, including directly condensing the inorganic nanoparticles with hydroxyl groups on the surface with compounds containing the organic group A or the organic group B, and also including modifying the inorganic nanoparticles with hydroxyl groups on the surface with a siloxane coupling agent and then polymerizing with an N-methylacrylate monomer with an alkyl side chain to obtain the prepared organic / inorganic hybrid nanoparticles; therefore, the technical scheme provided below in the present invention does not mean the sole designation or limitation of the preparation method of the organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups.

[0017] The present 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 and alkyl halide R 1 -X, and then subjected to tertiary amine substitution reaction, and separated and purified to prepare an N-methylethanol tertiary amine intermediate having an alkyl side chain; wherein the alkyl halide R 1 -X in R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, and X is a halogen atom;

[0019] (2) adding the N-methylethanol tertiary amine intermediate having an alkyl side chain obtained in step (1) to solvent A, an acid binding agent, and an inhibitor, and mixing them uniformly, performing a substitution reaction by adding an acyl halide, and preparing an N-methylacrylate monomer having an alkyl side chain after separation and purification;

[0020] (3) modifying the inorganic nanoparticles having hydroxyl groups on the surface with a siloxane coupling agent to prepare inorganic nanoparticles with surface double bond functional modification;

[0021] (4) adding the N-methylacrylate monomer with an alkyl side chain obtained in step (2) and the inorganic nanoparticles with surface double bond functional modification obtained in step (3) to solvent A and mixing them evenly, adding an initiator, and reacting them at 60 to 70° C. in an inert gas atmosphere for 12 to 24 hours. After the time is up, separating the solid product and drying it to obtain organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups.

[0022] In this context, the alkyl halide R 1-X, X is a halogen atom. According to the subsequent tertiary amination substitution reaction, those skilled in the art should know that it can be selected as a haloalkane. The haloalkane conventionally used in chemical production can be selected according to the common knowledge in the art, for example, X is fluorine, chlorine, bromine or iodine.

[0023] In one technical solution, the alkyl halide R in step (1) 1 -X can be selected from any one of bromopropane, n-butyl bromide, sec-butyl bromide, bromopentane, n-hexane bromide, 3-bromohexane, bromoheptane, 3-bromoheptane, n-nonane bromide, 2-bromononane, undecane bromide, 5-(bromomethyl)undecane, tridecane bromide, hexadecane bromide, 1-bromo-2-methylhexadecane, bromooctadecane, n-propane chloride, n-pentane chloride, n-hexane chloride, heptane chloride, n-nonane chloride, undecane chloride, dodecane chloride, and tetradecane chloride.

[0024] In this article, in step (1), the tertiary amination substitution reaction can be carried out by a person skilled in the art according to the present invention by reacting N-methylethanolamine with a haloalkyl R 1 -X selection, according to the common knowledge of chemical synthesis in the art, it is known that the tertiary amine substitution reaction is a nucleophilic substitution reaction, and its reaction conditions and reaction target products can refer to the conventional reaction between secondary amine and alkyl halide.

[0025] In order to better illustrate the present invention and provide a technical solution for reference, the tertiary amination substitution reaction in step (1) is specifically carried out by reacting N-methylethanolamine with a haloalkyl R 1 -X are mixed and then an alkaline solution is added, and the reaction is stirred at a temperature of 40 to 60°C for 12 to 24 hours; the alkaline solution is a solution prepared by dissolving a conventional alkaline salt in water in the chemical industry, such as a sodium hydroxide solution or a sodium carbonate solution with a molar concentration of 1 to 15 mol / L, and the liquid-to-solid ratio of the alkaline solution to N-methylethanolamine is (1 to 5) ml: 1 g, and the alkyl halide R 1 The molar ratio of -X to N-methylethanolamine is (1-1.5):1.

[0026] In this article, after the tertiary amine substitution reaction in step (1), it is necessary to separate and purify the N-methylethanol tertiary amine intermediate having an alkyl side chain. Those skilled in the art can refer to the conventional separation and purification process of the product after the reaction of secondary amine and alkyl halide, for example, sequentially perform extraction (for example, using dichloromethane or ethyl acetate), washing (for example, using saturated saline solution), drying, filtering and concentration. The specific steps and operations of the above separation and purification belong to the common knowledge in the technical field and will not be repeated here.

[0027] In this article, the N-methylethanol tertiary amine intermediate having an alkyl side chain is prepared in step (1), and its chemical reaction formula is as follows:

[0028]

[0029] In the formula, R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, and X is a halogen atom.

[0030] In this article, in step (2), the acyl halide is added to carry out the substitution reaction. Those skilled in the art can select the N-methylethanol tertiary amine intermediate with an alkyl side chain and the acyl halide provided by the present invention, and know that the substitution reaction is a nucleophilic substitution reaction according to the common knowledge of chemical synthesis in the art. The reaction conditions, acid binding agent, inhibitor and solvent selection, and the target reaction product can all refer to the conventional reaction of a hydroxyl-containing compound with an acyl halide.

[0031] In order 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] In order to better illustrate the present invention and provide a technical solution for reference, the inhibitor in step (2) is selected to include any one of hydroquinone, butylated hydroxytoluene or methoxyphenol.

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

[0034] Herein, the acyl halide in step (2) is a compound formed by replacing a hydroxyl group with a halogen atom, and the acyl halide conventionally used in chemical production can be selected according to the common knowledge in the art, for example, the halogen atom is fluorine, chlorine, bromine or iodine.

[0035] In order 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] In order to better illustrate the present invention and provide a technical solution for reference, the molar ratio of the N-methylethanol tertiary amine intermediate having an alkyl side chain to the acyl halide, the acid binding agent, and the inhibitor in step (2) is 1: (1-2.5): (1-3.5): (0.01-0.05).

[0037] In order to better illustrate the present invention and provide a technical solution for reference, the addition of acyl halide for substitution reaction in step (2) is, under laboratory conditions, specifically, adding acyl halide dropwise in an ice-water bath, and then stirring the reaction for 12 to 24 hours. In the implementation of industrial amplification, those skilled in the art can select appropriate reaction conditions according to actual conditions.

[0038] In this article, after the addition of the acyl halide for substitution reaction in step (2), it is necessary to separate and purify the N-methylacrylate monomer having an alkyl side chain. Those skilled in the art may refer to the conventional separation and purification process of the product after the reaction of the hydroxyl-containing compound with the acyl halide, for example, filtering, concentrating, washing with water, extracting (for example, using ethyl acetate or dichloromethane), alkali washing (for example, using saturated sodium bicarbonate or saturated sodium hydroxide solution), salt washing (for example, using saturated saline solution), drying (for example, adding a desiccant at room temperature for drying), filtering and concentrating in sequence. The specific steps and operations of the above separation and purification belong to the common knowledge in the technical field and will not be repeated here.

[0039] In this article, the N-methylacrylate monomer having an alkyl side chain is prepared in step (2), and its chemical reaction formula is as follows:

[0040]

[0041] In the formula, R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, R 2 is a hydrogen group or a methyl group, R 3 A halogen atom.

[0042] In this article, the inorganic nanoparticles having hydroxyl groups on the surface are modified by a siloxane coupling agent in step (3), wherein the modification of inorganic materials by a siloxane coupling agent is a conventional modification method in the art, and the specific modification conditions and operations can be referred to the instructions for use of the siloxane coupling agent or the records in the prior art literature.

[0043] In order to obtain a chemical structure that conforms to the organic group A and the organic group B, the siloxane coupling agent is γ-(methacryloyl chloride)propyltrimethoxysilane (KH570) or vinyltrimethoxysilane (KH171). It should be noted that other siloxane coupling agents can also be used in theory, but it is not yet known whether they can achieve the technical effect proposed by the present invention.

[0044] In this article, the inorganic nanoparticles having hydroxyl groups on the surface in step (3) are a type of inorganic nanoparticles having hydroxyl groups mainly due to surface oxidation reaction, such as any one or more of nano-silicon dioxide, nano-titanium dioxide, nano-zinc dioxide, nano-aluminum oxide, 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 having hydroxyl groups on the surface in step (3) is (1-10): (1-10).

[0046] In order to better illustrate the present invention and provide a technical solution for reference, the inorganic nanoparticles with hydroxyl groups on the surface are modified by a siloxane coupling agent in step (3), specifically, the inorganic nanoparticles with hydroxyl groups on the surface are dispersed in an organic solvent, and ammonia water and a siloxane coupling agent are added, and the reaction is stirred at a temperature of 12 to 50° C. for 24 to 48 hours; wherein the mass concentration of ammonia water is 25 to 27%, the material-liquid ratio of the inorganic nanoparticles with hydroxyl groups on the surface to the organic solvent is 1g: (50 to 200) ml, and the volume ratio of the organic solvent to ammonia water is (5 to 30): 1. It should be noted that the organic solvent used in this technical solution is a conventional organic solvent selected from the chemical industry, such as any one of anhydrous ethanol, n-hexane, cyclohexane, dichloromethane, n-heptane, n-octane, acetone, benzene, toluene, and ethyl acetate.

[0047] Herein, the initiator described in step (4) is an initiator commonly used in polymerization reactions in the technical field, and technicians in the technical field can select a suitable initiator according to actual needs.

[0048] In order 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 added amount of the initiator is 1% to 5% of the total mass of the N-methylacrylate monomer with an alkyl side chain and the inorganic nanoparticles modified with surface double bond functions.

[0049] In one of the technical solutions, the mass ratio of the inorganic nanoparticles modified with double bond functions on the surface to the N-methylacrylate monomer with alkyl side chains is (1-20): 1. The grafting amount is regulated by the mass ratio between the inorganic nanoparticles modified with double bond functions on the surface and the N-methylacrylate monomer with alkyl side chains. The higher the monomer feed ratio, the higher the relative grafted monomer content on the surface of the inorganic nanoparticles, that is, the higher the grafting density, and the better the hydrophobicity of the corresponding product, but the responsiveness will be reduced.

[0050] Based on the above findings and the conclusions of comparative experiments, in order to obtain organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups with better comprehensive hydrophobicity and responsiveness, in one of the preferred technical schemes, the grafting density is 9 to 13 g / g, and more preferably 10 to 12 g / g.

[0051] Herein, the stirring reaction is a stirring reaction conventionally used in the art, including magnetic stirring or mechanical stirring, and those skilled in the art can select a suitable stirring reaction mode according to the production scale or the current process conditions. In one technical solution, the stirring reaction can be carried out at a stirring rate of 100 to 300 rpm.

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

[0053] 1 part of organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups,

[0054] Solvent B 50-150 parts.

[0055] Herein, the 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 technical solution, the hydrophobic coating comprises, by weight, the following raw materials:

[0057] 1 to 5 parts of filler,

[0058] 1 to 5 parts of additives.

[0059] Among them, in order to improve the physical strength of the coating film after use, the raw material components include fillers, and the fillers are well-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. Furthermore, well-known and commonly used metal oxides are preferably used as both fillers and pigments.

[0060] The additive is one or more combinations of pigments, thermal inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants and rust inhibitors. Generally, the pigments, thermal inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants and rust inhibitors are well known and commonly used.

[0061] It should be noted that the hydrophobic coating provided by the present invention follows the conventional coating method of hydrophobic / hydrophilic coatings in the chemical industry. For example, after a layer of adhesive is coated on a substrate with a smooth surface, the hydrophobic coating is coated on the surface, and the hydrophobic coating is obtained after drying.

[0062] Typically, the coating method is one of spraying, brushing, and dipping; the adhesive includes but is not limited to 3M adhesive, common coating resin adhesive, inorganic adhesive, etc.; the substrate base material 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 the present invention regulates the hydrophobic chain length based on the selection of raw materials during its preparation process. When the hydrophobic chain length meets specific conditions (such as Example 1 below), it exhibits the property of being able to convert between hydrophilic and hydrophobic properties, and can thus be used as a pH-responsive hydrophilic-hydrophobic conversion coating. After being coated on a substrate to form a pH-responsive hydrophilic-hydrophobic conversion coating, when the surface of the pH-responsive hydrophilic-hydrophobic conversion coating is contacted with an acidic liquid with a pH of 1 to 5, the pH-responsive hydrophilic-hydrophobic conversion coating is converted from hydrophobic to hydrophilic.

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

[0065] 1. The present invention provides an organic / inorganic hybrid nanoparticle with integrated hydrophobic segments and responsive functional groups and a hydrophilic-hydrophobic conversion coating. The invention mainly controls the pH response behavior and the degree of hydrophilic-hydrophobic conversion by integrating the hydrophobic segments and the pH responsive functional groups into a molecular design and regulating the length of the hydrophobic chain. Starting from the molecular structure design, the invention provides new insights into the balance between the hydrophobic chain and the pH responsive hydrophilic-hydrophobic conversion.

[0066] 2. In the present invention, a hydrophobic segment and a pH-responsive functional group integrated organic / inorganic hybrid nanoparticle is provided, which integrates the hydrophobic segment and the pH-responsive group into a molecular structure, so as to finely regulate the response group and wettability through the length of the hydrophobic chain. In addition, the integrated organic / inorganic hybrid nanoparticle has a rough surface structure on the one hand, and the overall process is simple and controllable on the other hand, and the side chain length can be regulated according to specific needs.

[0067] 3. The organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups provided by the present invention have readily available raw materials for preparation, are inexpensive, do not require complex and expensive equipment, and have mild preparation conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 The surface morphology and element distribution diagram of the pH-responsive hydrophilic-hydrophobic conversion coating obtained in Example 1 of the present invention.

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

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

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

[0072] Figure 5 The thermogravimetric curves of the raw silica particles, intermediate products and the finally prepared organic / inorganic hybrid nanoparticles with different side chain lengths and integrated pH-responsive functional groups are compared in Examples 1 to 3 of the present invention. 2 refers to the raw material silica particles (30 nm) used in Examples 1 to 3, MPS-SiO 2 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-SiO 2 Refers to the organic / inorganic hybrid nanoparticles with a hydrophobic segment having a side chain length of 3 and a pH-responsive functional group obtained in Example 1; TA-C6 / MPS-SiO 2 Refers to the organic / inorganic hybrid nanoparticles with a hydrophobic segment having a side chain length of 6 and a pH-responsive functional group obtained in Example 2; TA-C9 / MPS-SiO 2 Refers to the organic / inorganic hybrid nanoparticles with a side chain length of 9 and a pH-responsive functional group obtained in Example 3. DETAILED DESCRIPTION

[0073] In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously change or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention. Although it is believed that those of ordinary skill in the art fully understand the following terms, the following definitions are still stated to help illustrate the subject matter disclosed by the present invention.

[0074] In one aspect, the present invention provides an organic / inorganic hybrid nanoparticle with an integrated hydrophobic segment and a pH-responsive functional group, which is an organic / inorganic hybrid nanoparticle connected by a covalent bond between an inorganic nanoparticle having a hydroxyl group on the surface and an organic group A or an organic group B, wherein the proportion of the organic group A or the organic group B is characterized by a 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, R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, R 2 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, R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, R 2 It is a hydrogen group or a methyl group, and n=5-150.

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

[0082] On the other hand, the present invention also provides a method for preparing the above-mentioned organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups, which is to form organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups by condensing some of the hydroxyl groups on the surface of the inorganic nanoparticles with hydroxyl groups and then forming silicon-oxygen bonds with the organic group A or the organic group B, so as to obtain the organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups. It should be noted that those skilled in the art can obtain specific preparation steps based on the above-mentioned technical content, including directly condensing the inorganic nanoparticles with hydroxyl groups on the surface with compounds containing the organic group A or the organic group B, and also including modifying the inorganic nanoparticles with hydroxyl groups on the surface with a siloxane coupling agent and then polymerizing with an N-methylacrylate monomer with an alkyl side chain to obtain the prepared organic / inorganic hybrid nanoparticles; therefore, the embodiments provided below in the present invention do not mean the sole designation or limitation of the preparation method of the organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups.

[0083] The present 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 and alkyl halide R 1 -X, and then subjected to tertiary amine substitution reaction, and separated and purified to prepare an N-methylethanol tertiary amine intermediate having an alkyl side chain; wherein the alkyl halide R 1 -X in R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, and X is a halogen atom;

[0085] (2) adding the N-methylethanol tertiary amine intermediate having an alkyl side chain obtained in step (1) to solvent A, an acid binding agent, and an inhibitor, and mixing them uniformly, performing a substitution reaction by adding an acyl halide, and preparing an N-methylacrylate monomer having an alkyl side chain after separation and purification;

[0086] (3) modifying the inorganic nanoparticles having hydroxyl groups on the surface with a siloxane coupling agent to prepare inorganic nanoparticles with surface double bond functional modification;

[0087] (4) adding the N-methylacrylate monomer with an alkyl side chain obtained in step (2) and the inorganic nanoparticles with surface double bond functional modification obtained in step (3) to solvent A and mixing them evenly, adding an initiator, and reacting them at 60 to 70° C. in an inert gas atmosphere for 12 to 24 hours. After the time is up, separating the solid product and drying it to obtain organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups.

[0088] In this context, the alkyl halide R 1 -X, X is a halogen atom. According to the subsequent tertiary amination substitution reaction, those skilled in the art should know that it can be selected as a haloalkane. The haloalkane conventionally used in chemical production can be selected according to the common knowledge in the art, for example, X is fluorine, chlorine, bromine or iodine.

[0089] In one embodiment, the alkyl halide R in step (1) 1 -X can be selected from any one of bromopropane, n-butyl bromide, sec-butyl bromide, bromopentane, n-hexane bromide, 3-bromohexane, bromoheptane, 3-bromoheptane, n-nonane bromide, 2-bromononane, undecane bromide, 5-(bromomethyl)undecane, tridecane bromide, hexadecane bromide, 1-bromo-2-methylhexadecane, bromooctadecane, n-propane chloride, n-pentane chloride, n-hexane chloride, heptane chloride, n-nonane chloride, undecane chloride, dodecane chloride, and tetradecane chloride.

[0090] In this article, in step (1), the tertiary amination substitution reaction can be carried out by a person skilled in the art according to the present invention by reacting N-methylethanolamine with a haloalkyl R 1-X selection, according to the common knowledge of chemical synthesis in the art, it is known that the tertiary amine substitution reaction is a nucleophilic substitution reaction, and its reaction conditions and reaction target products can refer to the conventional reaction between secondary amine and alkyl halide.

[0091] In order to better illustrate the present invention and provide an embodiment for reference, the tertiary amination substitution reaction in step (1) is specifically carried out by reacting N-methylethanolamine with a haloalkyl R 1 -X are mixed and then an alkaline solution is added, and the reaction is stirred at a temperature of 40 to 60°C for 12 to 24 hours; the alkaline solution is a solution prepared by dissolving a conventional alkaline salt in water in the chemical industry, such as a sodium hydroxide solution or a sodium carbonate solution with a molar concentration of 1 to 15 mol / L, and the liquid-to-solid ratio of the alkaline solution to N-methylethanolamine is (1 to 5) ml: 1 g, and the alkyl halide R 1 The molar ratio of -X to N-methylethanolamine is (1-1.5):1.

[0092] In this article, after the tertiary amine substitution reaction in step (1), it is necessary to separate and purify the N-methylethanol tertiary amine intermediate having an alkyl side chain. Those skilled in the art can refer to the conventional separation and purification process of the product after the reaction of secondary amine and alkyl halide, for example, sequentially perform extraction (for example, using dichloromethane or ethyl acetate), washing (for example, using saturated saline solution), drying, filtering and concentration. The specific steps and operations of the above separation and purification belong to the common knowledge in the technical field and will not be repeated here.

[0093] In this article, the N-methylethanol tertiary amine intermediate having an alkyl side chain is prepared in step (1), and its chemical reaction formula is as follows:

[0094]

[0095] In the formula, R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, and X is a halogen atom.

[0096] In this article, in step (2), the acyl halide is added to carry out the substitution reaction. Those skilled in the art can select the N-methylethanol tertiary amine intermediate with an alkyl side chain and the acyl halide provided by the present invention, and know that the substitution reaction is a nucleophilic substitution reaction according to the common knowledge of chemical synthesis in the art. The reaction conditions, acid binding agent, inhibitor and solvent selection, and the target reaction product can all refer to the conventional reaction of a hydroxyl-containing compound with an acyl halide.

[0097] In order to better illustrate the present invention and provide an implementation method 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.

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

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

[0100] Herein, the acyl halide in step (2) is a compound formed by replacing a hydroxyl group with a halogen atom, and the acyl halide conventionally used in chemical production can be selected according to the common knowledge in the art, for example, the halogen atom is fluorine, chlorine, bromine or iodine.

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

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

[0103] In order to better illustrate the present invention and provide an implementation method for reference, the addition of acyl halide for substitution reaction in step (2) is, under laboratory conditions, specifically, adding acyl halide dropwise in an ice-water bath, and then stirring the reaction for 12 to 24 hours. In the implementation of industrial amplification, those skilled in the art can select appropriate reaction conditions according to actual conditions.

[0104] In this article, after the addition of the acyl halide for substitution reaction in step (2), it is necessary to separate and purify the N-methylacrylate monomer having an alkyl side chain. Those skilled in the art may refer to the conventional separation and purification process of the product after the reaction of the hydroxyl-containing compound with the acyl halide, for example, filtering, concentrating, washing with water, extracting (for example, using ethyl acetate or dichloromethane), alkali washing (for example, using saturated sodium bicarbonate or saturated sodium hydroxide solution), salt washing (for example, using saturated saline solution), drying (for example, adding a desiccant at room temperature for drying), filtering and concentrating in sequence. The specific steps and operations of the above separation and purification belong to the common knowledge in the technical field and will not be repeated here.

[0105] In this article, the N-methylacrylate monomer having an alkyl side chain is prepared in step (2), and its chemical reaction formula is as follows:

[0106]

[0107] In the formula, R 1 is a linear or branched alkyl group having 1 to 18 carbon atoms, R 2 is a hydrogen group or a methyl group, R 3 A halogen atom.

[0108] In this article, the inorganic nanoparticles having hydroxyl groups on the surface are modified by a siloxane coupling agent in step (3), wherein the modification of inorganic materials by a siloxane coupling agent is a conventional modification method in the art, and the specific modification conditions and operations can be referred to the instructions for use of the siloxane coupling agent or the records in the prior art literature.

[0109] In order to obtain a chemical structure that conforms to the organic group A and the organic group B, the siloxane coupling agent is γ-(methacryloyl chloride)propyltrimethoxysilane (KH570) or vinyltrimethoxysilane (KH171). It should be noted that other siloxane coupling agents can also be used in theory, but it is not yet known whether they can achieve the technical effect proposed by the present invention.

[0110] In this article, the inorganic nanoparticles having hydroxyl groups on the surface in step (3) are a type of inorganic nanoparticles having hydroxyl groups mainly due to surface oxidation reaction, such as any one or more of nano-silicon dioxide, nano-titanium dioxide, nano-zinc dioxide, nano-aluminum oxide, nano-magnesium oxide, and nano-iron oxide.

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

[0112] In order to better illustrate the present invention and provide an embodiment for reference, the inorganic nanoparticles with hydroxyl groups on the surface are modified by a siloxane coupling agent in step (3), specifically, the inorganic nanoparticles with hydroxyl groups on the surface are dispersed in an organic solvent, and ammonia water and a siloxane coupling agent are added, and the reaction is stirred at a temperature of 12 to 50° C. for 24 to 48 hours; wherein the mass concentration of ammonia water is 25 to 27%, the material-liquid ratio of the inorganic nanoparticles with hydroxyl groups on the surface to the organic solvent is 1g: (50 to 200) ml, and the volume ratio of the organic solvent to ammonia water is (5 to 30): 1. It should be noted that the organic solvent used in this embodiment is a conventional organic solvent selected from 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] Herein, the initiator described in step (4) is an initiator commonly used in polymerization reactions in the technical field, and technicians in the technical field can select a suitable initiator according to actual needs.

[0114] In order to better illustrate the present invention and provide an implementation method for reference, the initiator selected in step (4) includes azobisisobutyronitrile or benzoyl peroxide; the added amount of the initiator is 1% to 5% of the total mass of the N-methylacrylate monomer with an alkyl side chain and the inorganic nanoparticles modified with surface double bond functions.

[0115] In one embodiment, the mass ratio of the inorganic nanoparticles modified with double bond functions on the surface to the N-methylacrylate monomer with alkyl side chains is (1-20): 1. The grafting amount is regulated by the mass ratio between the inorganic nanoparticles modified with double bond functions on the surface and the N-methylacrylate monomer with alkyl side chains. The higher the monomer feed ratio, the higher the relative grafted monomer content on the surface of the inorganic nanoparticles, that is, the higher the grafting density, and the better the hydrophobicity of the corresponding product, but the responsiveness will be reduced.

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

[0117] Herein, the stirring reaction is a stirring reaction conventionally used in the art, including magnetic stirring or mechanical stirring, and those skilled in the art can select a suitable stirring reaction mode according to the production scale or the current process conditions. In one embodiment, the stirring reaction can be carried out at a stirring rate of 100 to 300 rpm.

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

[0119] 1 part of organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups,

[0120] Solvent B 50-150 parts.

[0121] Herein, the 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 to 5 parts of filler,

[0124] 1 to 5 parts of additives.

[0125] Among them, in order to improve the physical strength of the coating film after use, the raw material components include fillers, and the fillers are well-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. Furthermore, well-known and commonly used metal oxides are preferably used as both fillers and pigments.

[0126] The additive is one or more combinations of pigments, thermal inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants and rust inhibitors. Generally, the pigments, thermal inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants and rust inhibitors are well known and commonly used.

[0127] It should be noted that the hydrophobic coating provided by the present invention follows the conventional coating method of hydrophobic / hydrophilic coatings in the chemical industry. For example, after a layer of adhesive is coated on a substrate with a smooth surface, the hydrophobic coating is coated on the surface, and the hydrophobic coating is obtained after drying.

[0128] Typically, the coating method is one of spraying, brushing, and dipping; the adhesive includes but is not limited to 3M adhesive, common coating resin adhesive, inorganic adhesive, etc.; the substrate base material 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 the present invention regulates the hydrophobic chain length based on the selection of raw materials during its preparation process. When the hydrophobic chain length meets specific conditions (such as Example 1 below), it exhibits the property of being able to convert between hydrophilic and hydrophobic properties, and can thus be used as a pH-responsive hydrophilic-hydrophobic conversion coating. After being coated on a substrate to form a pH-responsive hydrophilic-hydrophobic conversion coating, when the surface of the pH-responsive hydrophilic-hydrophobic conversion coating is contacted with an acidic liquid with a pH of 1 to 5, the pH-responsive hydrophilic-hydrophobic conversion coating is converted from hydrophobic to hydrophilic.

[0130] The present invention will be further explained in detail with reference to the following examples. However, it should be understood by those skilled in the art that these examples are provided for illustrative purposes only and are not intended to limit the present invention.

[0131] Example

[0132] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. The specific conditions not specified in the examples are carried out according to the conditions recommended by normal conditions or manufacturers. The reagents used or the instruments not specified by the manufacturer are all conventional products that can be obtained commercially. The application should not be construed as being limited to the specific examples described.

[0133] 1. Raw materials

[0134] N-methylethanolamine, propyl 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, aqueous ammonia, sodium chloride, sodium bicarbonate, sodium hydroxide and anhydrous sodium carbonate were provided by Chengdu Kelong Chemical Co., Ltd.

[0136] 2. Test Method

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

[0138] (2) The wetting properties of the coating surface were tested by a contact angle tester (Zhongchen digital equipment Co. Ltd., Shanghai, China).

[0139] (3) The grafting density was calculated based on the thermogravimetric analysis curve of the sample tested by a thermogravimetric analyzer (TG 209F1 instrument, NETZSCH, Germany). Specifically, it was calculated based on the “mass loss of organic / inorganic hybrid nanoparticles - mass loss of pure inorganic nanoparticles” divided by the “residual mass of organic / inorganic hybrid nanoparticles” at 700 °C, where the “mass loss of pure inorganic nanoparticles” was obtained by thermogravimetric analysis of the same mass of organic / inorganic hybrid nanoparticles as the control group.

[0140] Example 1

[0141] The present embodiment provides a method for preparing organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0142] (1) Preparation of N-methylethanol tertiary amine intermediate with an alkyl side chain length of 3: 15.1347 g (0.20 mol) of N-methylethanolamine and 27.0625 g (0.22 mol) of bromopropane were mixed, 30 mL of 10 mol / L sodium hydroxide solution was added and stirred for 12 h at 40°C. After the reaction, dichloromethane extraction, saturated brine washing, anhydrous sodium sulfate drying, filtration and concentration were performed in sequence to obtain N-methylethanol tertiary amine intermediate with an alkyl side chain length of 3.

[0143] (2) Preparation of N-methylacrylate monomer with an alkyl side chain length of 3: 11.7958 g (0.10 mol) of N-methylethanol tertiary amine intermediate with an 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, and 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, washed with saturated brine, dried, filtered, and concentrated to obtain an N-methylacrylate monomer with an alkyl side chain length of 3.

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

[0145] (4) Preparation of organic / inorganic hybrid nanoparticles with integrated hydrophobic segments with a side chain length of 3 and pH-responsive functional groups: 0.1 g of surface double-bond functionalized nano-silica particles, 0.05 g of N-methylacrylate monomer with an alkyl side chain length of 3, and 0.0020 g of azobisisobutyronitrile were added to 50 mL of tetrahydrofuran solvent. Nitrogen was introduced into a three-necked flask for 5 minutes, and the mixture was reacted at 65°C for 12 h. The mixture was washed with tetrahydrofuran and anhydrous ethanol, centrifuged, and dried at 80°C to obtain organic / inorganic hybrid nanoparticles with integrated hydrophobic segments with a side chain length of 3 and pH-responsive functional groups.

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

[0147] The morphology and element distribution of the organic / inorganic hybrid nanoparticles with a hydrophobic segment having a side chain length of 3 and a pH-responsive functional group are shown in FIG. Figure 1 As shown in Figure 2, the coating has a pH-responsive wetting behavior to a droplet at pH = 1, as Figure 2 shown.

[0148] Example 2

[0149] The present embodiment provides a method for preparing organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0150] (1) Preparation of N-methylethanol tertiary amine intermediate with an alkyl side chain length of 6: 15.0256 g (0.20 mol) of N-methylethanolamine and 36.3248 g (0.22 mol) of n-hexyl bromide were mixed, 30 mL of 10 mol / L sodium hydroxide solution was added and stirred for 12 h at 40°C. After the reaction, dichloromethane extraction, saturated brine washing, anhydrous sodium sulfate drying, filtration and concentration were performed in sequence to obtain N-methylethanol tertiary amine intermediate with an alkyl side chain length of 6.

[0151] (2) Preparation of N-methylacrylate monomer with an alkyl side chain length of 6: 16.0281 g (0.10 mol) of N-methylethanol tertiary amine intermediate with an 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, and 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 an N-methylacrylate monomer with an alkyl side chain length of 6.

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

[0153] (4) Preparation of organic / inorganic hybrid nanoparticles with integrated hydrophobic segments with a side chain length of 6 and pH-responsive functional groups: 0.2 g of surface double-bond functionalized nano-silica particles, 0.1 g of N-methylacrylate monomer with an alkyl side chain length of 6, and 0.015 g of azobisisobutyronitrile were added to 80 mL of tetrahydrofuran solvent. Nitrogen was introduced into a three-necked flask for 10 minutes, and the mixture was reacted at 65°C for 12 h. The mixture was washed with tetrahydrofuran and anhydrous ethanol, centrifuged, and dried at 80°C to obtain organic / inorganic hybrid nanoparticles with integrated hydrophobic segments with a side chain length of 6 and pH-responsive functional groups.

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

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

[0156] Example 3

[0157] The present embodiment provides a method for preparing organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0158] (1) Preparation of N-methylethanol tertiary amine intermediate with an alkyl side chain length of 9: 15.1092 g (0.20 mol) of N-methylethanolamine and 51.5773 g (0.25 mol) of n-nonane bromide were mixed, 30 mL of 10 mol / L sodium hydroxide solution was added and stirred for 12 h at 40°C. After the reaction, dichloromethane extraction, saturated brine washing, anhydrous sodium sulfate drying, filtration and concentration were performed in sequence to obtain N-methylethanol tertiary amine intermediate with an alkyl side chain length of 9.

[0159] (2) Preparation of N-methylacrylate monomer with an alkyl side chain length of 9: 26.1538 g (0.13 mol) of N-methylethanol tertiary amine intermediate with an 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, and 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 an N-methylacrylate monomer with an alkyl side chain length of 9.

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

[0161] (4) Preparation of organic / inorganic hybrid nanoparticles with integrated hydrophobic segments with a side chain length of 9 and pH-responsive functional groups: 0.25 g of surface double-bond functionalized nano-silica particles, 0.25 g of N-methylacrylate monomer with an alkyl side chain length of 9, and 0.0244 g of azobisisobutyronitrile were added to 50 mL of tetrahydrofuran solvent. Nitrogen was introduced into a three-necked flask for 10 minutes, and the mixture was reacted at 65°C for 12 h. The mixture was washed with tetrahydrofuran and anhydrous ethanol, centrifuged, and dried at 80°C to obtain organic / inorganic hybrid nanoparticles with integrated hydrophobic segments with a side chain length of 9 and pH-responsive functional groups.

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

[0163] The hydrophobic coating obtained in this example hardly exhibits pH-responsive wetting behavior to a droplet at pH = 1, such as Figure 4 shown.

[0164] Example 4

[0165] The present embodiment provides a method for preparing organic / inorganic hybrid nanoparticles integrating hydrophobic segments and pH-responsive functional groups, comprising the following steps:

[0166] (1) Preparation of N-methylethanol tertiary amine intermediate with an alkyl side chain length of 6: 15.6194 g (0.21 mol) of N-methylethanolamine and 45.5109 g (0.28 mol) of n-hexyl bromide were mixed, 50 mL of 10 mol / L sodium hydroxide solution was added and stirred for 12 h at 40°C. After the reaction, dichloromethane extraction, saturated brine washing, anhydrous sodium sulfate drying, filtration and concentration were performed in sequence to obtain N-methylethanol tertiary amine intermediate with an alkyl side chain length of 6.

[0167] (2) Preparation of N-methylacrylate monomer with an alkyl side chain length of 6: 17.5891 g (0.11 mol) of N-methylethanol tertiary amine intermediate with an 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, and 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 an N-methylacrylate monomer with an alkyl side chain length of 6.

[0168] (3) Preparation of inorganic nanoparticles with surface double bond functional modification: 1.2 g of silica particles (30 nm) were dispersed in 150 mL of ethanol and reacted with 2.2436 g of vinyltrimethoxysilane under the catalysis of 10 mL of 25% ammonia water at room temperature for 24 h to obtain nano-silica particles with surface double bond functional 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-methylacrylate monomer with an alkyl side chain length of 6, and 0.012 g of azobisisobutyronitrile were added to 100 mL of tetrahydrofuran solvent. Nitrogen was introduced into a three-necked flask for 10 minutes, and the mixture was reacted at 65°C for 12 hours. The mixture was washed with tetrahydrofuran and anhydrous ethanol, centrifuged, and dried at 80°C to obtain organic / inorganic hybrid nanoparticles with an integrated hydrophobic segment with a side chain length of 6 and a pH-responsive functional group.

[0170] The organic / inorganic hybrid nanoparticles with integrated hydrophobic segments of different side chain lengths and pH-responsive functional groups prepared in Examples 1 to 3 were subjected to thermogravimetric analysis. Figure 5 As shown, the grafting density is calculated, as shown in Table 1 below:

[0171] Table 1 Mass loss and residual mass information related to the thermal gravimetric curve and calculated grafting density

[0172]

[0173] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An organic / inorganic hybrid nanoparticle with integrated hydrophobic segments and pH-responsive functional groups, characterized in that Organic / inorganic hybrid nanoparticles are formed by covalently connecting inorganic nanoparticles with hydroxyl groups on the surface to organic groups A or organic groups B, wherein the proportion of organic groups A or organic groups B is characterized by the grafting density calculated by thermogravimetric analysis, and the grafting density is 8 to 15 g / g; The chemical structural formula of the organic group A is: In the formula, R1 is a linear or branched alkyl group having 1 to 18 carbon atoms, 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 linear or branched alkyl group having 1 to 18 carbon atoms, 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 The following steps are involved: (1) mixing N-methylethanolamine with an alkyl halide R1-X, subjecting the mixture to a tertiary amine substitution reaction, and separating and purifying the mixture to obtain an N-methylethanol tertiary amine intermediate having an alkyl side chain; wherein R1 in the alkyl halide R1-X is a linear or branched alkyl having 1 to 18 carbon atoms, and X is a halogen atom; (2) adding the N-methylethanol tertiary amine intermediate having an alkyl side chain obtained in step (1) to solvent A, an acid binding agent, and an inhibitor, and mixing them uniformly, performing a substitution reaction by adding an acyl halide, and preparing an N-methylacrylate monomer having an alkyl side chain after separation and purification; (3) modifying the inorganic nanoparticles having hydroxyl groups on the surface with a siloxane coupling agent to prepare inorganic nanoparticles with surface double bond functional modification; (4) adding the N-methylacrylate monomer with an alkyl side chain obtained in step (2) and the inorganic nanoparticles with surface double bond functional modification obtained in step (3) to solvent A and mixing them evenly, adding an initiator, and reacting them at 60 to 70° C. in an inert gas atmosphere for 12 to 24 hours. After the time is up, separating the solid product and drying it to obtain organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups.

3. The preparation method according to claim 2, characterized in that: The alkyl halide R1-X in step (1) includes any one of bromopropane, n-butyl bromide, sec-butyl bromide, bromopentane, n-hexane bromide, 3-bromohexane, bromoheptane, 3-bromoheptane, n-nonane bromide, 2-nonane bromide, undecane bromide, 5-(bromomethyl)undecane, tridecane bromide, hexadecane bromide, 1-bromo-2-methylhexadecane, octadecane bromide, n-propane chloride, n-pentane chloride, n-hexane chloride, heptane chloride, n-nonane chloride, undecane chloride, dodecane chloride, and tetradecane chloride.

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

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

6. The preparation method according to claim 2, characterized in that: The acyl halide in step (2) can be selected from 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 in step (3) is γ-(methacryloyl chloride)propyltrimethoxysilane or vinyltrimethoxysilane.

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

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

1.

10. A hydrophobic coating using the organic / inorganic hybrid nanoparticles integrating the hydrophobic segments and pH-responsive functional groups as claimed in claim 1 as the main component, characterized in that The raw materials mainly include: 1 part of organic / inorganic hybrid nanoparticles with integrated hydrophobic segments and pH-responsive functional groups, Solvent B 50-150 parts.

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