Janus particle crosslinker and two-step method of preparation and uses thereof

Abstract

This invention discloses a Janus particle crosslinking agent, a two-step preparation method, and its applications, belonging to the field of functional coating technology. The Janus particle crosslinking agent comprises SiO2 particles, one end of which is modified with a hydrophilic isocyanate group, and the other end with a low surface energy material, hydrogen-containing silicone oil. The Janus particle crosslinking agent with the hydrogen-containing silicone oil as the hydrophobic side can achieve directional arrangement, thereby imparting excellent hydrophobic properties to the coating. Utilizing the isocyanate group of the Janus particle crosslinking agent, it can not only exert its crosslinking effect in the coating but also stabilize the toluene / water Pickering emulsion. The two-step preparation method involves using hydrogen-containing silicone oil as a modifier to prepare J(SiO2·PMHS) particles via the Pickering emulsion interface method; then, using isocyanate propyltriethoxysilane as a modifier, a one-pot method is used to prepare the Janus particle crosslinking agent with the isocyanate group as the hydrophilic end and the hydrogen-containing silicone oil as the hydrophobic end. The isocyanate groups in the crosslinking agent are directly modified on one side of the Janus particles, thereby enabling them to play their crosslinking role in the coating and improving the wear resistance of the coating.

Description

Technical Field

[0001] This invention belongs to the field of functional coating technology, specifically relating to a Janus particle crosslinking agent and a two-step preparation method and its application. Background Technology

[0002] Superhydrophobic surfaces are materials whose surfaces possess hydrophobic properties, meaning water droplets do not easily diffuse or adhere to them. A key characteristic of superhydrophobic surfaces is a water contact angle greater than 150° and a water roll-off angle less than 10°. With rapid technological advancements and societal progress, superhydrophobic materials have demonstrated enormous application potential in various fields. However, superhydrophobic materials still face several significant challenges, the most prominent being their poor wear resistance in practical applications. Furthermore, many current superhydrophobic materials with low surface energy are composed of fluorinated chemicals, which pose potential environmental hazards. Therefore, improving the wear resistance of superhydrophobic materials, seeking alternatives to fluorinated chemicals with low surface energy, and promoting the development of environmentally friendly superhydrophobic materials are crucial for expanding their application areas and achieving sustainable development.

[0003] Janus particles are a class of binary synergistic nanomaterials exhibiting anisotropy in spatial and physicochemical properties, with each property independent of the others. Janus particles are endowed with a variety of functions, such as magnetism, optical activity, and superhydrophobicity, by controlling the distribution of different sides of solid particles. For example, a wear-resistant superhydrophobic coating was prepared by utilizing the amphiphilicity of Janus particles. Li et al. (Yifan Li, Fei Liu, Shensheng Chen, Ayuna Tsyrenova, Kyle Miller, Emily Olson, Rebecca Mort, Devin Palm, Chunhui Xiang, Xin Yong, Shan Jiang. Self-stratification of amphiphilic Janus particles at coating surfaces[J]. Materials Horizons, 2020, 7(8): 2047-2055.) mixed asymmetric wettable Janus particles with homogeneous binder particles with strong adhesion, and formed a robust hydrophobic coating through a unique self-stratification process. The water contact angle reached 130° and it was resistant to solvent washing. The study found that the self-stratification phenomenon is due to the strong adsorption of Janus particles at the water-air interface. However, the interaction between the Janus particles prepared by this method and the binder is weak, resulting in relatively poor wear resistance of the constructed coating. Furthermore, the Janus particles are prepared using a seed emulsion polymerization method, which is relatively cumbersome and yields only moderate hydrophobic effects. Therefore, selecting a simpler process suitable for preparing high-performance wear-resistant superhydrophobic coatings is of great significance. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a Janus particle crosslinking agent and a two-step preparation method and its application, so as to solve the technical problems of relatively poor wear resistance of the coating constructed by Janus particles prepared by the prior art and the cumbersome process of preparation by seed emulsion polymerization.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] This invention provides a Janus particle crosslinking agent, which includes SiO2 particles, one end of which is a hydrophilic group and the other end is a low surface energy material; wherein the hydrophilic group is an isocyanate group and the low surface energy material is a hydrogen-containing silicone oil.

[0007] This invention also provides a two-step preparation method for a Janus particle crosslinking agent, comprising the following steps:

[0008] S1: SiO2 particles, deionized water, toluene, hexadecyltrimethylammonium bromide, hydrogen-containing silicone oil, dibutyltin dilaurate, and anhydrous ethanol were ultrasonically emulsified and stirred to carry out interfacial reaction to obtain Pickering emulsion. The Pickering emulsion was placed in a low temperature environment, and after the Pickering emulsion was demulsified, it was centrifuged, washed, and dried to obtain J(SiO2·PMHS) particles.

[0009] S2: J(SiO2·PMHS) particles, toluene, and propyltriethoxysilane isocyanate are mixed, ultrasonically dispersed, nitrogen gas is introduced, and after heating and reaction, the mixture is centrifuged, washed, and dried to obtain Janus particle crosslinking agent.

[0010] In the specific implementation process, in S1, the feeding ratio of SiO2 particles, deionized water, toluene, hexadecyltrimethylammonium bromide, hydrogen-containing silicone oil, dibutyltin dilaurate, and anhydrous ethanol is (0.1~2.0)g:(10~100)ml:(2~30)ml:(0.12~0.62)g:(0.2~2.0)g:(0.05~0.2)g:(1.0~10.0)g.

[0011] In the specific implementation process, in S1, the frequency of ultrasonic emulsification is 45-80kHz, the ultrasonic emulsification time is 30-60min, the interface reaction time is 1-12h, the temperature of the low-temperature environment is -18--24℃, and the particle size range of the SiO2 particles in S1 is 150nm-3000nm.

[0012] In the specific implementation process, in S2, the feeding ratio of J(SiO2·PMHS) particles, toluene, and propyltriethoxysilane isocyanate is (0.1~1.0)g:(10~100)ml:(0.5~1.0)g.

[0013] In the specific implementation process, in S2, the frequency of ultrasonic dispersion is 45-80kHz, the ultrasonic dispersion time is 30-50min; the time for introducing nitrogen gas is 5-20min; the temperature of the heating reaction is 50-70℃, and the heating reaction time is 6-12h.

[0014] This invention also provides the application of Janus particle crosslinking agent in the preparation of wear-resistant superhydrophobic coatings.

[0015] In specific implementation, the process of preparing the wear-resistant superhydrophobic coating is as follows:

[0016] After spraying an epoxy resin solution onto the substrate surface and drying it to a semi-dry state, a Janus particle crosslinking agent solution is sprayed onto it and then dried to obtain a wear-resistant superhydrophobic coating.

[0017] In the specific implementation process, the solvent in the epoxy resin solution is acetone and ethyl acetate, wherein the feeding ratio of acetone and ethyl acetate is (1.5~3)g:(1.5~3)g;

[0018] The concentration of the epoxy resin solution is 0.1–0.2 g / ml;

[0019] The amount of epoxy resin sprayed onto the substrate surface is 0.008–0.016 g / cm³. 2 .

[0020] In the specific implementation process, the solvent in the Janus particle crosslinking agent solution is ethanol; the concentration of the Janus particle crosslinking agent solution is 0.012–0.072 g / ml;

[0021] The spraying amount of the Janus particle crosslinking agent solution on the substrate surface is 0.01–0.06 g / cm³. 2 .

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention provides a Janus particle crosslinking agent, wherein one end of the SiO2 particles is modified with a hydrophilic isocyanate group, and the other end is modified with a low surface energy material, hydrogen-containing silicone oil. The Janus particle crosslinking agent with hydrogen-containing silicone oil as the hydrophobic side can achieve directional arrangement, thereby giving the coating excellent hydrophobic properties. The isocyanate group of the Janus particle crosslinking agent can not only exert its crosslinking effect in the coating, but also stabilize the toluene / water Pickering emulsion.

[0024] This invention provides a two-step preparation method for a Janus particle crosslinking agent. First, using hydrogen-containing silicone oil as a modifier, J(SiO2·PMHS) particles are prepared via the Pickering emulsion interface method. Then, using isocyanate propyltriethoxysilane as a modifier, a one-pot method is employed to prepare a Janus particle crosslinking agent with isocyanate groups as the hydrophilic end and hydrogen-containing silicone oil as the hydrophobic end. This preparation method employs a novel approach that eliminates the need for external crosslinking agents, directly modifying one side of the Janus particles with isocyanate groups from the crosslinking agent. This allows the particles to exert their crosslinking effect in the coating while simultaneously improving the coating's wear resistance.

[0025] Furthermore, the superhydrophobic coating prepared by the present invention based on Janus particle crosslinking agent has a water contact angle as high as 167.2±1.9°, and its surface still has superhydrophobicity after 80 friction cycle tests.

[0026] This invention also provides the application of Janus particle crosslinking agent in the preparation of wear-resistant superhydrophobic coatings. Through a layer-by-layer spraying method, the hydrophilic and hydrophobic interactions of Janus particle crosslinking agent drive its directional arrangement on the surface of an aqueous epoxy coating. Then, by utilizing the inherent particle effect of Janus particle crosslinking agent and its hydrophobic segments, the micro-nano rough structure and low surface energy necessary for superhydrophobicity are simultaneously achieved. The wear resistance of the superhydrophobic coating is achieved by utilizing the chemical crosslinking between the hydrophilic isocyanate groups of Janus particle crosslinking agent and the epoxy groups in the epoxy resin. Attached Figure Description

[0027] Figure 1 This is a schematic diagram showing the test results of the DLS particle size of SiO2 particles, J(SiO2·PMHS) particles and Janus particles crosslinking agents in Example 7 of the present invention.

[0028] Figure 2 This is a schematic diagram showing the Zeta potential test results of the SiO2 particles, J(SiO2·PMHS) particles and Janus particles crosslinking agents of the present invention.

[0029] Figure 3 A schematic diagram illustrating the wear resistance of a superhydrophobic coating constructed using Janus particle crosslinking agent;

[0030] Figure 4 A schematic diagram showing the water contact angle test results of the coating constructed based on SiO2 particles and Janus particle crosslinking agent;

[0031] Figure 5 An upright microscope photograph of the Janus particle crosslinking agent used in this invention to replace surfactants in stabilizing toluene / water Pickering emulsions. Detailed Implementation

[0032] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0033] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0034] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0035] In this article, unless otherwise specified, the terms “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of”. For example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a”.

[0036] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0037] This invention provides a Janus particle crosslinking agent, a two-step preparation method, and its application.

[0038] The first aspect of the present invention provides a Janus particle crosslinking agent, which includes SiO2 particles, one end of which is modified with a hydrophilic isocyanate group, and the other end is modified with a low surface energy material, hydrogen-containing silicone oil.

[0039] The second aspect of this invention provides a two-step preparation method for a Janus particle crosslinking agent, which is obtained by this method. The preparation process involves first dispersing SiO2 particles in a toluene / water Pickering emulsion, then using hydrogen-containing silicone oil as a modifier to prepare J(SiO2·PMHS) particles with hydroxyl groups as hydrophilic ends and hydrogen-containing silicone oil as hydrophobic ends through an interfacial reaction. Subsequently, the J(SiO2·PMHS) particles are dispersed in a toluene solution, and using propyltriethoxysilane isocyanate as a modifier, a Janus particle crosslinking agent with isocyanate groups as hydrophilic ends and hydrogen-containing silicone oil as hydrophobic ends is prepared. This invention provides a two-step method for preparing a Janus particle crosslinking agent, replacing the cumbersome traditional Janus particle preparation process, and preparing the Janus particle crosslinking agent in two steps.

[0040] The specific preparation process is as follows:

[0041] Step 1): SiO2 particles, deionized water, toluene, hexadecyltrimethylammonium bromide, hydrogen-containing silicone oil, dibutyltin dilaurate, and anhydrous ethanol were ultrasonically emulsified for a period of time. The mixture was then magnetically stirred at room temperature for a period of time. During the stirring process, an interfacial reaction occurred. After stirring, a Pickering emulsion was obtained. The Pickering emulsion was placed in a low-temperature environment for 12 hours. After the Pickering emulsion broke down, it was centrifuged, washed, and dried to obtain J(SiO2·PMHS) particles.

[0042] Step 2): J(SiO2·PMHS) particles, toluene, and propyltriethoxysilane isocyanate are mixed, ultrasonically dispersed for a period of time, nitrogen gas is introduced for a period of time, and after heating and reaction, the mixture is centrifuged, washed, and dried to obtain Janus particle crosslinking agent.

[0043] In the specific implementation process, in step 1), the feed ratio of SiO2 particles, deionized water, toluene, hexadecyltrimethylammonium bromide, hydrogen-containing silicone oil, dibutyltin dilaurate, and anhydrous ethanol is (0.1–2.0) g: (10–100) ml: (2–30) ml: (0.12–0.62) g: (0.2–2.0) g: (0.05–0.2) g: (1.0–10.0) g. The ultrasonic emulsification frequency is 45–80 kHz, the ultrasonic emulsification time is 30–60 min, the interfacial reaction time is 1–12 h, and the low-temperature environment temperature is -18–-24 °C; the particle size range of SiO2 particles is 150 nm–3000 nm.

[0044] In the specific implementation process, in step 2), the feeding ratio of J(SiO2·PMHS) particles, toluene, and propyltriethoxysilane is (0.1~1.0)g:(10~100)ml:(0.5~1.0)g, the ultrasonic dispersion frequency is 45~80kHz, the ultrasonic dispersion time is 30~50min, the nitrogen gas is introduced for 5~20min, the heating reaction temperature is 50~70℃, and the reaction time is 6~12h.

[0045] The two-step preparation method of the present invention provides an efficient and simple method for preparing Janus particle crosslinking agent, in which the crosslinking groups play a key role in simultaneously improving the hydrophobicity and wear resistance of the coating.

[0046] The third aspect of the present invention provides the application of Janus particle crosslinking agent prepared by a two-step preparation method in the preparation of wear-resistant superhydrophobic coatings.

[0047] This crosslinking agent can chemically crosslink with the epoxy resin on the substrate surface, utilizing the crosslinking effect of isocyanate groups and epoxy groups to form a stable and wear-resistant superhydrophobic coating on the substrate surface.

[0048] The specific process for preparing the wear-resistant superhydrophobic coating is as follows:

[0049] First, an epoxy resin solution is sprayed onto the substrate surface and dried in an oven until semi-dry. Then, a Janus particle crosslinking agent solution is sprayed onto the substrate surface and dried to obtain a wear-resistant superhydrophobic coating.

[0050] The epoxy resin solution uses acetone and ethyl acetate as solvents, with an acetone-to-ethyl acetate feed ratio of (1.5–3) g:(1.5–3) g, resulting in a concentration of 0.1–0.2 g / ml. The spraying amount of the epoxy resin solution on the substrate surface is 0.008–0.016 g / cm³. 2 The Janus particle crosslinking agent solution is a solution using ethanol as a solvent with a concentration of 0.012–0.072 g / ml; the spraying amount of the Janus particle crosslinking agent solution on the substrate surface is 0.01–0.06 g / cm³. 2 .

[0051] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0052] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0053] Example 1

[0054] A method for preparing a Janus particle crosslinking agent includes the following steps:

[0055] Step 1) Mix 0.1g of SiO2 particles with a particle size of 150nm, 10ml of deionized water, 2ml of toluene, 0.62g of hexadecyltrimethylammonium bromide, 0.2g of hydrogen-containing silicone oil, 0.2g of dibutyltin dilaurate, and 1.0g of anhydrous ethanol. Emulsify at an ultrasonic frequency of 80kHZ for 30min. After magnetic stirring at room temperature for 1h, a Pickering emulsion is obtained. Place the Pickering emulsion at a low temperature of -18℃. After the Pickering emulsion breaks down, centrifuge, wash, and dry to obtain J(SiO2·PMHS) particles.

[0056] Step 2) Mix 0.1g of J(SiO2·PMHS) particles with 100ml of toluene and ultrasonically disperse at a frequency of 45kHZ for 30min. Then add 0.5g of isocyanate propyltriethoxysilane to the system, purge with nitrogen for 20min, heat to 50℃, react for 12h, centrifuge, wash, and dry to obtain Janus particle crosslinking agent.

[0057] A wear-resistant superhydrophobic coating was prepared based on the above-mentioned Janus particle crosslinking agent:

[0058] Prepare an epoxy resin spraying solution with a concentration of 0.2 g / ml by mixing 1.5 g acetone and 1.5 g ethyl acetate. The spraying amount is 0.016 g / cm³. 2 After drying in an oven until semi-dry, spray with an ethanol solution of Janus particle crosslinking agent at a concentration of 0.072 g / ml, at a spraying rate of 0.06 g / cm³. 2 After drying, a wear-resistant superhydrophobic coating is obtained.

[0059] Example 2

[0060] A method for preparing a Janus particle crosslinking agent includes the following steps:

[0061] Step 1) Mix 2.0g of SiO2 particles with a particle size of 3000nm, 100ml of deionized water, 30ml of toluene, 0.12g of hexadecyltrimethylammonium bromide, 2.0g of hydrogen-containing silicone oil, 0.05g of dibutyltin dilaurate, and 10.0g of anhydrous ethanol. Emulsify at an ultrasonic frequency of 45kHZ for 60min. After magnetic stirring at room temperature for 12h, a Pickering emulsion is obtained. Place the Pickering emulsion at a low temperature of -19℃. After the Pickering emulsion breaks down, centrifuge, wash, and dry to obtain J(SiO2·PMHS) particles.

[0062] Step 2) Mix 1.0g of J(SiO2·PMHS) particles with 10ml of toluene and ultrasonically disperse at an ultrasonic frequency of 80kHZ for 50min. Then add 1.0g of isocyanate propyltriethoxysilane to the system, purge with nitrogen gas for 5min, heat to 70℃, react for 6h, centrifuge, wash, and dry to obtain Janus particle crosslinking agent.

[0063] A wear-resistant superhydrophobic coating was prepared based on the above-mentioned Janus particle crosslinking agent:

[0064] Prepare an epoxy resin spraying solution with a concentration of 0.1 g / ml by mixing 3.0 g acetone and 3.0 g ethyl acetate. The spraying amount is 0.008 g / cm³. 2After drying in an oven until semi-dry, spray with an ethanol solution of Janus particle crosslinking agent at a concentration of 0.012 g / ml, at a spraying amount of 0.01 g / cm³. 2 After drying, a wear-resistant superhydrophobic coating is obtained.

[0065] Example 3

[0066] A method for preparing a Janus particle crosslinking agent includes the following steps:

[0067] Step 1) Mix 0.8g of SiO2 particles with a particle size of 200nm, 30ml of deionized water, 5ml of toluene, 0.038g of cetyltrimethylammonium bromide, 0.25g of hydrogen-containing silicone oil, 0.06g of dibutyltin dilaurate, and 5.0g of anhydrous ethanol. Emulsify at an ultrasonic frequency of 50kHZ for 35min. After magnetic stirring at room temperature for 6h, a Pickering emulsion is obtained. Place the Pickering emulsion in a low temperature environment of -20℃. After the Pickering emulsion breaks down, centrifuge, wash, and dry to obtain J(SiO2·PMHS) particles.

[0068] Step 2) Mix 0.5g of J(SiO2·PMHS) particles with 10ml of toluene and ultrasonically disperse at a frequency of 70kHZ for 45min. Then add 0.6g of isocyanate propyltriethoxysilane to the system, purge with nitrogen for 20min, heat to 55℃, react for 8h, centrifuge, wash, and dry to obtain Janus particle crosslinking agent.

[0069] A wear-resistant superhydrophobic coating was prepared based on the above-mentioned Janus particle crosslinking agent:

[0070] Prepare an epoxy resin spraying solution with a concentration of 0.15 g / ml by mixing 2.0 g acetone and 1.5 g ethyl acetate. The spraying amount is 0.010 g / cm³. 2 After drying in an oven until semi-dry, spray with an ethanol solution of Janus particle crosslinking agent at a concentration of 0.012 g / ml, at a spraying amount of 0.01 g / cm³. 2 After drying, a wear-resistant superhydrophobic coating is obtained.

[0071] Example 4

[0072] A method for preparing a Janus particle crosslinking agent includes the following steps:

[0073] Step 1) Mix 1.5g of SiO2 particles with a particle size of 2000nm, 50ml of deionized water, 10ml of toluene, 0.2g of hexadecyltrimethylammonium bromide, 0.5g of hydrogen-containing silicone oil, 0.1g of dibutyltin dilaurate, and 8.0g of anhydrous ethanol. Emulsify at an ultrasonic frequency of 60kHZ for 55min. After magnetic stirring at room temperature for 5h, a Pickering emulsion is obtained. Place the Pickering emulsion at a low temperature of -21℃. After the Pickering emulsion breaks down, centrifuge, wash, and dry to obtain J(SiO2·PMHS) particles.

[0074] Step 2) Mix 0.8g of J(SiO2·PMHS) particles with 30ml of toluene and ultrasonically disperse at a frequency of 75kHZ for 35min. Then add 0.8g of isocyanate propyltriethoxysilane to the system, purge with nitrogen for 15min, heat to 65℃, react for 9h, centrifuge, wash, and dry to obtain Janus particle crosslinking agent.

[0075] A wear-resistant superhydrophobic coating was prepared based on the above-mentioned Janus particle crosslinking agent:

[0076] Prepare an epoxy resin spraying solution with a concentration of 0.1 g / ml by mixing 1.5 g acetone and 2.0 g ethyl acetate. The spraying amount is 0.015 g / cm³. 2 After drying in an oven until semi-dry, spray with an ethanol solution of Janus particle crosslinking agent at a concentration of 0.034 g / ml, at a spraying rate of 0.05 g / cm³. 2 After drying, a wear-resistant superhydrophobic coating is obtained.

[0077] Example 5

[0078] A method for preparing a Janus particle crosslinking agent includes the following steps:

[0079] Step 1) Mix 0.5g of SiO2 particles with a particle size of 1500nm, 80ml of deionized water, 25ml of toluene, 0.4g of hexadecyltrimethylammonium bromide, 0.8g of hydrogen-containing silicone oil, 0.15g of dibutyltin dilaurate, and 4.0g of anhydrous ethanol. Emulsify at an ultrasonic frequency of 75kHZ for 40min. After magnetic stirring at room temperature for 10h, a Pickering emulsion is obtained. Place the Pickering emulsion at a low temperature of -22℃. After the Pickering emulsion breaks down, centrifuge, wash, and dry to obtain J(SiO2·PMHS) particles.

[0080] Step 2) Mix 0.6g of J(SiO2·PMHS) particles with 25ml of toluene and ultrasonically disperse at a frequency of 55kHZ for 40min. Then add 0.55g of isocyanate propyltriethoxysilane to the system, purge with nitrogen for 12min, heat to 60℃, react for 11h, centrifuge, wash, and dry to obtain Janus particle crosslinking agent.

[0081] A wear-resistant superhydrophobic coating was prepared based on the above-mentioned Janus particle crosslinking agent:

[0082] Prepare an epoxy resin spraying solution with a concentration of 0.15 g / ml by mixing 3.0 g acetone and 2.0 g ethyl acetate. The spraying amount is 0.008 g / cm³. 2 After drying in an oven until semi-dry, spray with an ethanol solution of Janus particle crosslinking agent at a concentration of 0.042 g / ml, at a spraying amount of 0.03 g / cm³. 2 After drying, a wear-resistant superhydrophobic coating is obtained.

[0083] Example 6

[0084] A method for preparing a Janus particle crosslinking agent includes the following steps:

[0085] Step 1) Mix 1.0g of SiO2 particles with a particle size of 750nm, 90ml of deionized water, 20ml of toluene, 0.42g of hexadecyltrimethylammonium bromide, 1.5g of hydrogen-containing silicone oil, 0.12g of dibutyltin dilaurate, and 6.0g of anhydrous ethanol. Emulsify at an ultrasonic frequency of 70kHZ for 50min. After magnetic stirring at room temperature for 2h, obtain a Pickering emulsion. Place the Pickering emulsion in a low temperature environment of -23℃. After the Pickering emulsion breaks down, centrifuge, wash, and dry to obtain J(SiO2·PMHS) particles.

[0086] Step 2) Mix 0.4g of J(SiO2·PMHS) particles with 20ml of toluene and ultrasonically disperse at a frequency of 65kHZ for 50min. Then add 0.65g of isocyanate propyltriethoxysilane to the system, purge with nitrogen for 10min, heat to 70℃, react for 7h, centrifuge, wash, and dry to obtain Janus particle crosslinking agent.

[0087] A wear-resistant superhydrophobic coating was prepared based on the above-mentioned Janus particle crosslinking agent:

[0088] Prepare an epoxy resin spraying solution with a concentration of 0.1 g / ml by mixing 2.0 g acetone and 3.0 g ethyl acetate. The spraying amount is 0.016 g / cm³. 2After drying in an oven until semi-dry, spray with an ethanol solution of Janus particle crosslinking agent at a concentration of 0.062 g / ml, at a spraying amount of 0.04 g / cm³. 2 After drying, a wear-resistant superhydrophobic coating is obtained.

[0089] Example 7

[0090] A method for preparing a Janus particle crosslinking agent includes the following steps:

[0091] Step 1) Mix 1.0g of SiO2 particles with a particle size of 531nm, 90ml of deionized water, 20ml of toluene, 0.6g of hexadecyltrimethylammonium bromide, 1.0g of hydrogen-containing silicone oil, 0.2g of dibutyltin dilaurate, and 6.0g of anhydrous ethanol. Emulsify at an ultrasonic frequency of 70kHZ for 50min. After magnetic stirring at room temperature for 2h, obtain a Pickering emulsion. Place the Pickering emulsion in a low temperature environment of -24℃. After the Pickering emulsion breaks down, centrifuge, wash, and dry to obtain J(SiO2·PMHS) particles.

[0092] Step 2) Mix 0.4g of J(SiO2·PMHS) particles with 20ml of toluene and ultrasonically disperse at a frequency of 65kHZ for 50min. Then add 0.65g of isocyanate propyltriethoxysilane to the system, purge with nitrogen for 10min, heat to 70℃, react for 7h, centrifuge, wash, and dry to obtain Janus particle crosslinking agent.

[0093] A wear-resistant superhydrophobic coating was prepared based on the above-mentioned Janus particle crosslinking agent:

[0094] Prepare an epoxy resin spraying solution with a concentration of 0.1 g / ml by mixing 2.0 g acetone and 3.0 g ethyl acetate. The spraying amount is 0.016 g / cm³. 2 After drying in an oven until semi-dry, spray with an ethanol solution of Janus particle crosslinking agent at a concentration of 0.062 g / ml, at a spraying amount of 0.04 g / cm³. 2 After drying, a wear-resistant superhydrophobic coating is obtained.

[0095] Figure 1The figure shows the DLS particle size test results of SiO2 particles, J(SiO2·PMHS) particles, and Janus particle crosslinking agents in Example 7. As can be seen from the figure, compared to the SiO2 particle size of 531 nm, the particle size distribution of J(SiO2·PMHS) particles is mainly concentrated at 615 nm, while the particle size distribution of the amphiphilic Janus particle crosslinking agent is mainly concentrated at 825 nm. These results indicate that the particle size of SiO2 particles significantly increases during the formation of the Janus particle crosslinking agent. This increase in particle size is mainly due to the introduction of hydrogen-containing silicone oil and propyltriethoxysilane isocyanate onto the surface of the SiO2 particles, respectively. Hydrogen-containing silicone oil is a transparent oily liquid containing a large number of silicon-hydrogen bonds within its molecules. These silicon-hydrogen bonds have certain chemical activity; under the catalysis of dibutyltin dilaurate, the silicon-hydrogen bonds break, releasing hydrogen gas, which is then replaced by hydroxyl groups to form silanols. Subsequently, the hydroxyl groups on the surface of some SiO2 particles immersed in the oil phase undergo a condensation reaction with the silanol groups in the hydrogen-containing silicone oil to form J(SiO2·PMHS) particles. Then, propyltriethoxysilane is added, where the three methoxy groups undergo hydrolysis to generate silanol groups, which then form stable silicon-oxygen bonds with the hydroxyl groups on the surface of the J(SiO2·PMHS) particles through a condensation reaction. This ultimately forms a Janus particle crosslinking agent, resulting in a gradual increase in particle size as shown in particle size tests.

[0096] Figure 2 The figure shows the zeta potential test results for SiO2 particles, J(SiO2·PMHS) particles, and Janus particle crosslinking agents. As can be seen from the figure, the zeta potential of SiO2 particles is approximately -18.1 mV, which is due to the negative charge of the hydroxyl groups on the surface of the SiO2 particles. After modification with hydrogen-containing silicone oil, the positive charge of the hydrogen-containing silicone oil shifts the zeta potential of J(SiO2·PMHS) particles in the positive direction to -6.4 mV, while the zeta potential of the Janus particle crosslinking agent is +33 mV. This is because after grafting with propyltriethoxysilane isocyanate, the negatively charged hydroxyl groups on the surface of J(SiO2·PMHS) particles are completely replaced by the positively charged propyltriethoxysilane, resulting in a significant increase in the zeta potential of the Janus particle crosslinking agent.

[0097] Figure 3This paper presents the wear resistance of a superhydrophobic coating constructed using Janus particle crosslinking agent. As shown in the figure, without friction, the water contact angle and roll-off angle of the superhydrophobic coating are 163.8±1.7° and 2.6±0.3°, respectively, exhibiting excellent superhydrophobic properties. With increasing friction cycles, the water contact angle gradually decreases while the roll-off angle gradually increases. After 80 friction cycles, the water contact angle and roll-off angle of the superhydrophobic coating are 151.1±3.2° and 9.2±0.2°, respectively, still maintaining superhydrophobicity. This is because during friction, the chemical crosslinking reaction and physical adhesion between the Janus particle crosslinking agent and the epoxy coating effectively prevent the detachment of the Janus particle crosslinking agent from the coating surface, thereby enhancing the wear resistance and superhydrophobic properties of the coating.

[0098] Figure 4 The figure shows the water contact angle test results for coatings constructed using SiO2 particles and Janus particles as crosslinking agents. As can be seen from the figure, the water contact angle of the coating constructed using Janus particles as crosslinking agents is 163.8 ± 1.7°, exhibiting excellent hydrophobic properties. In contrast, the water contact angle of the coating constructed using SiO2 particles is only 27.9 ± 0.6°.

[0099] Figure 5 This is an upright microscope image showing the use of Janus particle crosslinking agent to stabilize toluene / water Pickering emulsions as a surfactant. The isocyanate groups on the Janus particle crosslinking agent were labeled with amino-containing fluorescein 5-AF, and the distribution of the crosslinking agent in the Pickering emulsion was observed using an upright microscope. As shown in the figure, the Janus particle crosslinking agent successfully emulsified the toluene / water mixture, forming a milky white emulsion layer. Furthermore, the Janus particle crosslinking agent formed emulsion droplets with a diameter of 20–40 μm in the Pickering emulsion, exhibiting relatively uniform particle size and distribution. This result further demonstrates the amphiphilic structure of the Janus particle crosslinking agent, laying the foundation for its application in the construction of wear-resistant superhydrophobic coatings.

[0100] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A Janus particle crosslinker characterized in that, The Janus particle crosslinking agent includes SiO2 particles, one end of which is a hydrophilic group and the other end is a low surface energy material; wherein, the hydrophilic group is an isocyanate group and the low surface energy material is a hydrogen-containing silicone oil. The two-step preparation method of the Janus particle crosslinking agent includes the following steps: S1: SiO2 particles, deionized water, toluene, hexadecyltrimethylammonium bromide, hydrogen-containing silicone oil, dibutyltin dilaurate, and anhydrous ethanol were ultrasonically emulsified and stirred to carry out interfacial reaction to obtain Pickering emulsion. The Pickering emulsion was placed in a low temperature environment, and after the Pickering emulsion was demulsified, it was centrifuged, washed, and dried to obtain J(SiO2·PMHS) particles. S2: J(SiO2·PMHS) particles, toluene, and propyltriethoxysilane isocyanate were mixed, ultrasonically dispersed, nitrogen gas was introduced, heated to react, centrifuged, washed and dried to obtain Janus particle crosslinking agent; In S1, the feeding ratio of SiO2 particles, deionized water, toluene, hexadecyltrimethylammonium bromide, hydrogen-containing silicone oil, dibutyltin dilaurate, and anhydrous ethanol is (0.1~2.0) g: (10~100) mL: (2~30) mL: (0.12~0.62) g: (0.2~2.0) g: (0.05~0.2) g: (1.0~10.0) g.

2. The Janus particle crosslinker of claim 1, wherein, In step S1, the frequency of ultrasonic emulsification is 45~80kHz, the ultrasonic emulsification time is 30~60min, the interface reaction time is 1~12h, and the temperature of the low-temperature environment is -18~-24℃; in step S1, the particle size range of the SiO2 particles is 150nm~3000nm.

3. The Janus particle crosslinker of claim 1, wherein, In S2, the feeding ratio of J(SiO2·PMHS) particles, toluene, and propyltriethoxysilane is (0.1~1.0) g: (10~100) mL: (0.5~1.0) g.

4. The Janus particle crosslinker of claim 1, wherein, In step S2, the ultrasonic dispersion frequency is 45~80kHz, the ultrasonic dispersion time is 30~50min; the nitrogen gas introduction time is 5~20min; the heating reaction temperature is 50~70℃, and the heating reaction time is 6~12h.

5. The application of the Janus particle crosslinking agent according to claim 1 in the preparation of wear-resistant superhydrophobic coatings; The process for preparing the wear-resistant superhydrophobic coating is as follows: After spraying an epoxy resin solution onto the substrate surface and drying it to a semi-dry state, a Janus particle crosslinking agent solution is sprayed onto it and then dried to obtain a wear-resistant superhydrophobic coating.

6. Use according to claim 5, characterized in that, The solvent in the epoxy resin solution is acetone and ethyl acetate, wherein the feeding ratio of acetone and ethyl acetate is (1.5~3) g: (1.5~3) g; The concentration of the epoxy resin solution is 0.1~0.2 g / mL; The epoxy resin is sprayed on the surface of the substrate at a quantity of 0.008-0.016 g / cm 2 .

7. Use according to claim 5, characterized in that, The solvent in the Janus particle crosslinking agent solution is ethanol; the concentration of the Janus particle crosslinking agent solution is 0.012~0.072 g / mL; The spraying amount of the Janus particle crosslinking agent solution on the surface of the substrate is 0.01-0.06 g / cm 2 .

Images