Preparation method of super-biphobic silicon carbide film with self-cleaning function

Abstract

The application discloses a preparation method of super-amphiphobic silicon carbide film with self-cleaning function, which comprises the following steps: a) performing oxidation treatment on the silicon carbide film to obtain the silicon carbide film after oxidation treatment; b) mixing nano-particles and micro-particles with different particle sizes to obtain micro-nano blended particles, then adding the micro-nano blended particles and a silane coupling agent into ethanol to obtain a suspension; c) adding a fluorine-containing low-surface-energy substance into ethanol to obtain an impregnation solution; d) spraying the suspension on the surface of the silicon carbide film after oxidation treatment, and performing heat curing at 55-65 DEG C for 15-45 minutes to obtain a modified silicon carbide film; and e) immersing the modified silicon carbide film in the impregnation solution for graft modification, taking out, and performing heat curing at 55-65 DEG C for 15-45 minutes to obtain the super-amphiphobic silicon carbide film. The preparation method is simple, the reaction condition is mild, and the prepared super-amphiphobic silicon carbide film has the self-cleaning function and good chemical stability.

Description

Technical Field

[0001] This invention relates to a method for preparing a superhydrophobic silicon carbide film with self-cleaning function, belonging to the field of superhydrophobic materials technology. Background Technology

[0002] Silicon carbide membranes are widely used in water treatment and resource recycling due to their excellent chemical inertness, acid and alkali resistance, and high membrane flux. However, in practical applications, the surface of silicon carbide membranes is easily fouled, which reduces their efficiency and limits their application. Therefore, it is necessary to perform appropriate surface treatment on silicon carbide membranes to give them self-cleaning properties, thereby effectively preventing contamination and corrosion. Surfaces with self-cleaning properties are typically superhydrophobic and low-adhesion surfaces, with a water contact angle greater than 150° and a roll-off angle less than 10°.

[0003] Currently, the main approach is to first prepare a superhydrophobic coating or suspension, and then coat the membrane material surface with the superhydrophobic coating or suspension through spraying, dipping, brushing, or other methods to form a superhydrophobic surface on the membrane material, thereby obtaining a superhydrophobic membrane material.

[0004] Chinese patent "CN202110655287.1 A method for preparing a super-hydrophobic and waterproof breathable membrane" describes a process where an organosilane-based waterproof and oil-repellent finishing agent and a super-hydrophobic finishing agent are prepared separately. The organosilane-based finishing agent is then coated onto an organic microporous membrane via dip coating, brushing, or spraying. After curing, the super-hydrophobic finishing agent is further coated onto the organic microporous membrane, and after further curing, a waterproof, oil-repellent, and breathable membrane with super-hydrophobic and waterproof properties is obtained. However, this patent requires the addition of an initiator during the preparation of the super-hydrophobic finishing agent and necessitates a reaction under ultraviolet light irradiation. The preparation method is complex, the reaction conditions are harsh, making large-scale production difficult. Furthermore, this patent does not address the chemical stability of the breathable membrane.

[0005] Chinese patent "CN202210228845.0 A method for preparing a fluorinated epoxy resin clay mineral superhydrophobic and breathable membrane" describes a method that involves first preparing a superhydrophobic suspension, then coating it onto the surface of a waterproof and breathable membrane by spraying, and finally heat-curing it at 90–120°C for 30–60 minutes to obtain a stable superhydrophobic and breathable membrane. Compared to the waterproof and oil-resistant breathable membrane prepared in patent CN202110655287.1, the superhydrophobic and breathable membrane prepared by this patent exhibits both superhydrophobic and breathable properties and excellent chemical stability. However, the preparation process of the superhydrophobic suspension in this patent requires the separate preparation of fluorinated epoxy resin binder and low surface energy fluorinated micro / nanoparticles, followed by adding the low surface energy fluorinated micro / nanoparticles to the fluorinated epoxy resin binder and ultrasonically dispersing them to obtain the superhydrophobic suspension. Among them, the preparation of fluorinated epoxy resin bonding agent requires the addition of an initiator and the reaction under ultraviolet light. The preparation of low surface energy fluorinated micro and nano particles requires the reaction under nitrogen protection. The preparation methods are complex and the reaction conditions are harsh, making it difficult to scale up production.

[0006] Chinese patent "CN202210982940.X A Superhydrophobic Coating with Micro-Nano Composite Structure and Its Preparation Method" utilizes the hydrolysis reaction of tetraethyl orthosilicate and ammonia gas volatilized in vacuum to grow micro-nano-scale secondary surface roughness structures in situ on the surface of micron or nano-sized silica, thereby preparing a superhydrophobic coating. The prepared superhydrophobic coating is directly sprayed onto the surface of the workpiece to form a superhydrophobic coating layer. Compared to patents CN202210228845.0 and CN202110655287.1, while the preparation of this patented superhydrophobic coating does not require initiators and ultraviolet light irradiation, it requires a specialized vapor deposition apparatus. This vapor deposition apparatus includes a vapor deposition chamber container and storage chamber containers located on both sides, resulting in complex operation procedures, high costs, and difficulty in large-scale production. Summary of the Invention

[0007] In view of the above-mentioned problems in the existing technology, the purpose of this invention is to provide a method for preparing a superhydrophobic silicon carbide film that is simple to prepare, has mild reaction conditions, good chemical stability, and has self-cleaning function.

[0008] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a superhydrophobic silicon carbide film with self-cleaning function includes the following steps:

[0010] a) The silicon carbide film is oxidized to obtain an oxidized silicon carbide film;

[0011] b) First, mix nanoparticles and microparticles of different sizes to obtain micro-nano blended particles. Then, add the micro-nano blended particles and silane coupling agent to ethanol and stir to mix them evenly to obtain a suspension.

[0012] c) Add the fluorine-containing low surface energy material to ethanol and stir to mix evenly to obtain the impregnation solution;

[0013] d) The suspension is sprayed onto the surface of the oxidized silicon carbide film and then thermally cured at 55-65°C for 15-45 minutes to obtain a modified silicon carbide film;

[0014] e) The modified silicon carbide film is immersed in the impregnation solution for graft modification, taken out, and heat-cured at 55-65℃ for 15-45 minutes to obtain a superhydrophobic silicon carbide film.

[0015] In one embodiment, step a) involves oxidizing the silicon carbide film, specifically as follows:

[0016] The silicon carbide film was oxidized at 800-900℃ for 2-4 hours. After oxidation, it was cooled to room temperature and then ultrasonically cleaned in water and ethanol for 3-10 minutes respectively. After cleaning, it was dried at 55-65℃ to obtain the oxidized silicon carbide film.

[0017] In one embodiment, in step b), the micron-particles and nanoparticles are any one of silicon dioxide, aluminum oxide, and titanium dioxide.

[0018] In one embodiment, in step b), nanoparticles and microparticles are mixed at a mass ratio of 1:(0.5-3).

[0019] In one embodiment, in step b), the particle size range of the nanoparticles is 70–500 nm, and the particle size range of the microparticles is 1–2 μm.

[0020] In one embodiment, in step b), the silane coupling agent is at least one of (3-aminopropyl)triethoxysilane, bis(3-trimethoxysilylpropyl)amine, and diethoxydimethoxysilane.

[0021] In one embodiment, in step b), the mass ratio of micro / nano blended particles to silane coupling agent is 1:(1-5); the mass ratio of micro / nano blended particles to ethanol is 1:(10-30).

[0022] In one embodiment, in step c), the fluorinated low surface energy substance is a fluorosilane coupling agent, and the fluorosilane coupling agent is at least one selected from 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, and 1H,1H,2H,2H-perfluorododecyltrimethoxysilane.

[0023] In one embodiment, in step c), the mass ratio of fluorine-containing low surface energy substance to ethanol is 1:(50-100).

[0024] In one embodiment, in step d), a suspension is sprayed onto the surface of an oxidized silicon carbide film using a spray gun. The spraying pressure is 0.2–0.7 MPa, and the spraying distance is 10–15 cm.

[0025] In one embodiment, in step e), the modified silicon carbide film is immersed in an impregnation solution for graft modification for 1 to 3 hours.

[0026] Compared with the prior art, the present invention has the following significant advantages:

[0027] 1. This invention employs a spraying and impregnation method to modify the surface of a silicon carbide film: First, nanoparticles and microparticles of different sizes are mixed to obtain micro-nano blended particles. Then, a suspension containing micro-nano blended particles is sprayed onto the surface of the silicon carbide film to form a fine and rich micro-nano rough structure, thereby obtaining a lower roll-off angle. Then, the sprayed silicon carbide film is impregnated in an impregnation solution, and the silicon carbide film is grafted and modified using fluorine-containing low surface energy substances in the impregnation solution to reduce the surface energy of the silicon carbide film. This forms a micron-level dense and nano-level fine superhydrophobic coating on the surface of the silicon carbide film, giving the silicon carbide film excellent superhydrophobic and low adhesion properties, making the silicon carbide film self-cleaning and strong anti-fouling characteristics.

[0028] 2. In the spraying process of this invention, micro-nano blended particles and silane coupling agent are dispersed in ethanol to obtain a suspension. The suspension is then sprayed onto the surface of a silicon carbide film. The silane coupling agent functions as both a coupling agent and an adhesive. Without the need to add other adhesives, the adhesion of the coating to the surface of the silicon carbide film can be improved, thereby improving the durability of the superhydrophobic silicon carbide film in practical applications. This results in the superhydrophobic silicon carbide film having good acid and alkali resistance and good chemical stability.

[0029] 3. This invention uses an oxidized silicon carbide film as a substrate, which can effectively improve the superhydrophobic properties of the final prepared silicon carbide film;

[0030] 4. The present invention only requires simple stirring and mixing of the corresponding liquid to obtain suspension and impregnation solution. No initiator, ultraviolet light irradiation, nitrogen protection, or specific equipment are required in the preparation process. The preparation method is simple, the conditions are mild, and it is suitable for large-scale production. Attached Figure Description

[0031] Figure 1These are scanning electron microscope (SEM) images of the silicon carbide film and the super-amphihydro silicon carbide film after oxidation treatment in Example 1 of the present invention; wherein, (a) is a SEM image of the surface of the silicon carbide film after oxidation treatment, (b) is a cross-sectional SEM image of the silicon carbide film after oxidation treatment, (c) is a surface SEM image of the super-amphihydro silicon carbide film, and (d) is a cross-sectional SEM image of the super-amphihydro silicon carbide film.

[0032] Figure 2 Photographs showing the contact angles of water, sulfuric acid solution droplets (pH=1), and sodium hydroxide droplets (pH=12) on the surface of a superhydrophobic silicon carbide film in Example 1 of this invention;

[0033] Figure 3 These are photographs of water and different oil droplets on the surface of a superhydrophobic silicon carbide film in Example 1 of the present invention;

[0034] Figure 4 These are test images of the self-cleaning performance of the silicon carbide film surface after oxidation treatment (a) and the superhydrophobic silicon carbide film surface (b) in Example 1 of the present invention.

[0035] Figure 5 The diagram shows the corrosion resistance test results of the super-dihydrophobic silicon carbide film in Example 1 of the present invention; wherein, (a) is a diagram showing the change in contact angle of the super-dihydrophobic silicon carbide film after immersing it in a solution with pH=1 for 48 hours, and (b) is a diagram showing the change in contact angle of the super-dihydrophobic silicon carbide film after immersing it in a solution with pH=12 for 48 hours. Detailed Implementation

[0036] The technical solution of the present invention will be further described in detail and completely below with reference to the embodiments.

[0037] Example 1

[0038] a) The silicon carbide film was oxidized at 850℃ for 3 hours. After the oxidation was completed, it was cooled to room temperature and then placed in water and ethanol for ultrasonic cleaning for 5 minutes each. After cleaning, it was removed and dried at 60℃ to obtain the oxidized silicon carbide film.

[0039] b) First, mix 500nm silica nanoparticles and 2μm silica microparticles at a mass ratio of 1:1 to obtain micro-nano blended particles. Then, add the micro-nano blended particles and (3-aminopropyl)triethoxysilane to ethanol and stir at 300 rpm for 30 minutes to mix evenly and obtain a suspension. The mass ratio of micro-nano blended particles to (3-aminopropyl)triethoxysilane is 1:1, and the mass ratio of micro-nano blended particles to ethanol is 1:10.

[0040] c) Add 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol and stir at 300 rpm for 30 minutes to mix evenly to obtain an impregnation solution, wherein the mass ratio of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol is 1:50.

[0041] d) The suspension was sprayed onto the surface of the oxidized silicon carbide film using a spray gun with an inner diameter of 10 μm. The spraying pressure was 0.2 MPa and the spraying distance was 10 cm. The film was then heat-cured at 60 °C for 30 minutes to obtain the modified silicon carbide film.

[0042] e) The modified silicon carbide film is immersed in the impregnation solution for graft modification for 1 hour, then removed and heat-cured at 60°C for 30 minutes to obtain a superhydrophobic silicon carbide film.

[0043] Figure 1 These are scanning electron microscope (SEM) images of the silicon carbide film and the super-amphihydro silicon carbide film after oxidation treatment in this embodiment; wherein, (a) is a SEM image of the surface of the silicon carbide film after oxidation treatment, (b) is a cross-sectional SEM image of the silicon carbide film after oxidation treatment, (c) is a surface SEM image of the super-amphihydro silicon carbide film, and (d) is a cross-sectional SEM image of the super-amphihydro silicon carbide film; as can be seen from the figures, the super-amphihydro silicon carbide film obtained after spraying and impregnation treatment has a dense coating on its surface compared to the unmodified silicon carbide film.

[0044] The superhydrophobic properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0045] Figure 2 The images show the contact angles of water, sulfuric acid solution droplets (pH=1), and sodium hydroxide droplets (pH=12) on the surface of the superhydrophobic silicon carbide film in this embodiment. As can be seen from the images, the contact angles of the superhydrophobic silicon carbide film prepared in this embodiment with water, sulfuric acid solution droplets (pH=1), and sodium hydroxide droplets (pH=12) are 152.4°, 151.3°, and 150.6°, respectively, all of which are greater than 150°. The superhydrophobic silicon carbide film prepared in this embodiment has good hydrophobicity to neutral water, acidic water, and alkaline water. Figure 3 The image shows water and different oil droplets on the surface of a superhydrophobic silicon carbide film in Example 1 of this invention; as can be seen from the image, the superhydrophobic silicon carbide film has excellent hydrophobic and oleophobic properties.

[0046] The water contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of water. The results were: water contact angle of 152.4° and water roll-off angle of 5.2°. The oil contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil and mineral oil, respectively. The results were: oil contact angles of 150.6°, 152.0°, 151.3° and 150.8°, respectively, and oil roll-off angles of 7.9°, 8.1°, 8.0° and 8.3°, respectively.

[0047] Therefore, the superhydrophobic silicon carbide film prepared in this embodiment has excellent superhydrophobic properties.

[0048] The self-cleaning properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0049] The oxidized silicon carbide membrane and the superaphthoic silicon carbide membrane were placed at a 10° angle on a petri dish. A layer of fine sand with a particle size of 10 μm was spread on the surface. Approximately 2 mL of water was dropped onto the top of the membrane using a micropipette. The behavior of the water droplet and the fine sand on the membrane surface was observed. The test results were obtained. Figure 4 As shown.

[0050] Figure 4 The figures show the self-cleaning performance test results of (a) the oxidized silicon carbide film surface and (b) the super-amphihydrosilicon carbide film surface in this embodiment. As can be seen from the figures, water droplets can easily roll and carry away the fine sand on the surface of the super-amphihydrosilicon carbide film, indicating that the super-amphihydrosilicon carbide film prepared in this embodiment has good self-cleaning properties.

[0051] The acid and alkali resistance properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0052] The superamphetophilic silicon carbide film was immersed in solutions with pH values ​​of 1 and 12, respectively, and the change in contact angle was recorded every 6 hours. The test results are as follows: Figure 5 As shown.

[0053] Figure 5 The figures show the corrosion resistance test results of the superhydrophobic silicon carbide film in this embodiment. (a) shows the contact angle change of the superhydrophobic silicon carbide film after immersion in a solution with pH=1 for 48 hours, and (b) shows the contact angle change of the superhydrophobic silicon carbide film after immersion in a solution with pH=12 for 48 hours. As can be seen from the figures, whether immersed in a solution with pH=1 or pH=12 for 48 hours, the water contact angle of the superhydrophobic silicon carbide film is still greater than 147°, and the contact angle of n-hexadecane is still greater than 145°. This indicates that the superhydrophobic film prepared by this invention has good acid and alkali resistance and good chemical stability.

[0054] Example 2

[0055] a) The silicon carbide film was oxidized at 850℃ for 3 hours. After the oxidation was completed, it was cooled to room temperature and then placed in water and ethanol for ultrasonic cleaning for 5 minutes each. After cleaning, it was removed and dried at 60℃ to obtain the oxidized silicon carbide film.

[0056] b) First, 70 nm silica nanoparticles and 2 μm silica microparticles are mixed at a mass ratio of 1:1 to obtain micro-nano blended particles. Then, the micro-nano blended particles and di(3-trimethoxysilylpropyl)amine are added to ethanol and stirred at 400 rpm for 30 minutes to mix evenly and obtain a suspension. The mass ratio of micro-nano blended particles to di(3-trimethoxysilylpropyl)amine is 1:2, and the mass ratio of micro-nano blended particles to ethanol is 1:15.

[0057] c) Add 1H,1H,2H,2H-perfluorooctyltriethoxysilane to ethanol and stir at 400 rpm for 30 minutes to mix evenly to obtain an impregnation solution, wherein the mass ratio of 1H,1H,2H,2H-perfluorooctyltriethoxysilane to ethanol is 1:60.

[0058] d) The suspension was sprayed onto the surface of the oxidized silicon carbide film using a spray gun with an inner diameter of 10 μm. The spraying pressure was 0.4 MPa and the spraying distance was 10 cm. The film was then heat-cured at 60 °C for 30 minutes to obtain the modified silicon carbide film.

[0059] e) The modified silicon carbide film is immersed in the impregnation solution for graft modification for 2 hours, then removed and heat-cured at 60°C for 30 minutes to obtain a superhydrophobic silicon carbide film.

[0060] The superhydrophobic properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0061] The water contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of water. The results showed that the water contact angle was 154.2° and the roll-off angle was 4.6°. The oil contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil, and mineral oil, respectively. The results showed that the contact angles were 151.2°, 152.1°, 152.3°, and 151.9°, and the roll-off angles were 7.8°, 7.8°, 7.7°, and 8.0°, respectively. This indicates that the superhydrophobic silicon carbide film prepared in this example has excellent superhydrophobic properties.

[0062] The self-cleaning properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0063] The superhydrophobic silicon carbide membrane was tilted at 10° and placed on a petri dish. A layer of fine sand with a particle size of 10 μm was spread on the surface. About 2 mL of water was dropped onto the top of the membrane using a micropipette. The water droplet could easily roll and carry away the fine sand on the surface of the superhydrophobic membrane. This shows that the superhydrophobic silicon carbide membrane prepared in this example has good self-cleaning properties.

[0064] The acid and alkali resistance properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0065] The superhydrophobic silicon carbide membrane was immersed in solutions with pH values ​​of 1 and 12, respectively, and the change in contact angle was recorded every 6 hours. After 48 hours, the water contact angle of the superhydrophobic silicon carbide membrane was still greater than 148°, and the hexadecane contact angle was still greater than 145°. This indicates that the superhydrophobic membrane prepared by the present invention has good acid and alkali resistance and good chemical stability.

[0066] Example 3

[0067] a) The silicon carbide film was oxidized at 850℃ for 3 hours. After the oxidation was completed, it was cooled to room temperature and then placed in water and ethanol for ultrasonic cleaning for 5 minutes each. After cleaning, it was removed and dried at 60℃ to obtain the oxidized silicon carbide film.

[0068] b) First, mix 70nm silica nanoparticles and 1μm silica microparticles at a mass ratio of 1:1 to obtain micro-nano blended particles. Then, add the micro-nano blended particles and diethoxydimethoxysilane to ethanol and stir at 600 rpm for 30 minutes to mix evenly and obtain a suspension. The mass ratio of micro-nano blended particles to diethoxydimethoxysilane is 1:3, and the mass ratio of micro-nano blended particles to ethanol is 1:20.

[0069] c) Add 1H,1H,2H,2H-perfluorododecyltrimethoxysilane to ethanol and stir at 600 rpm for 30 minutes to mix evenly to obtain an impregnation solution, wherein the mass ratio of 1H,1H,2H,2H-perfluorododecyltrimethoxysilane to ethanol is 1:70.

[0070] d) The suspension was sprayed onto the surface of the oxidized silicon carbide film using a spray gun with an inner diameter of 10 μm. The spraying pressure was 0.5 MPa and the spraying distance was 12 cm. The film was then heat-cured at 60 °C for 30 minutes to obtain the modified silicon carbide film.

[0071] e) The modified silicon carbide film is immersed in the impregnation solution for graft modification for 2 hours, then removed and heat-cured at 60°C for 30 minutes to obtain a superhydrophobic silicon carbide film.

[0072] The superhydrophobic properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0073] The water contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of water. The results showed that the water contact angle was 153.0° and the roll-off angle was 6.6°. The oil contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil, and mineral oil, respectively. The results showed that the contact angles were 151.0°, 151.8°, 152.1°, and 151.4°, respectively, and the roll-off angles were 7.9°, 7.6°, 7.5°, and 8.0°, respectively. This indicates that the superhydrophobic silicon carbide film prepared in this example has excellent superhydrophobic properties.

[0074] The self-cleaning properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0075] The superhydrophobic silicon carbide membrane was tilted at 10° and placed on a petri dish. A layer of fine sand with a particle size of 10 μm was spread on the surface. About 2 mL of water was dropped onto the top of the membrane using a micropipette. The water droplet could easily roll and carry away the fine sand on the surface of the superhydrophobic membrane. This shows that the superhydrophobic silicon carbide membrane prepared in this example has good self-cleaning properties.

[0076] The acid and alkali resistance properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0077] The superhydrophobic silicon carbide membrane was immersed in solutions with pH values ​​of 1 and 12, respectively, and the change in contact angle was recorded every 6 hours. After 48 hours, the water contact angle of the superhydrophobic silicon carbide membrane was still greater than 147°, and the hexadecane contact angle was still greater than 144°. This indicates that the superhydrophobic membrane prepared by the present invention has good acid and alkali resistance and good chemical stability.

[0078] Example 4

[0079] a) The silicon carbide film was oxidized at 850℃ for 3 hours. After the oxidation was completed, it was cooled to room temperature and then placed in water and ethanol for ultrasonic cleaning for 5 minutes each. After cleaning, it was removed and dried at 60℃ to obtain the oxidized silicon carbide film.

[0080] b) First, alumina particles of 100 nm, 500 nm, and 1 μm are mixed in a mass ratio of 1:1:1 to obtain micro-nano blended particles. Then, the micro-nano blended particles, (3-aminopropyl)triethoxysilane, and diethoxydimethoxysilane are added to ethanol and stirred at 500 rpm for 30 minutes to ensure uniform mixing and obtain a suspension. The mass ratio of micro-nano blended particles to (3-aminopropyl)triethoxysilane to diethoxydimethoxysilane is 1:2:2, and the mass ratio of micro-nano blended particles to ethanol is 1:25.

[0081] c) Add 1H,1H,2H,2H-perfluorodecyltriethoxysilane and 1H,1H,2H,2H-perfluorododecyltrimethoxysilane to ethanol and stir at 500 rpm for 30 minutes to mix evenly to obtain an impregnation solution. The mass ratio of the total amount of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to 1H,1H,2H,2H-perfluorododecyltrimethoxysilane to ethanol is 1:80.

[0082] d) The suspension was sprayed onto the surface of the oxidized silicon carbide film using a spray gun with an inner diameter of 10 μm. The spraying pressure was 0.6 MPa and the spraying distance was 15 cm. The film was then heat-cured at 60 °C for 30 minutes to obtain the modified silicon carbide film.

[0083] e) The modified silicon carbide film is immersed in the impregnation solution for graft modification for 1 hour, then removed and heat-cured at 60°C for 30 minutes to obtain a superhydrophobic silicon carbide film.

[0084] The superhydrophobic properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0085] The water contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of water. The results showed that the water contact angle was 152.4° and the roll-off angle was 7.2°. The oil contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil, and mineral oil, respectively. The results showed that the contact angles were 151.0°, 150.9°, 151.7°, and 151.4°, respectively, and the roll-off angles were 8.3°, 8.0°, 7.7°, and 8.3°, respectively. This indicates that the superhydrophobic silicon carbide film prepared in this example has excellent superhydrophobic properties.

[0086] The self-cleaning properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0087] The superhydrophobic silicon carbide membrane was tilted at 10° and placed on a petri dish. A layer of fine sand with a particle size of 10 μm was spread on the surface. About 2 mL of water was dropped onto the top of the membrane using a micropipette. The water droplet could easily roll and carry away the fine sand on the surface of the superhydrophobic membrane. This shows that the superhydrophobic silicon carbide membrane prepared in this example has good self-cleaning properties.

[0088] The acid and alkali resistance properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0089] The superhydrophobic silicon carbide membrane was immersed in solutions with pH values ​​of 1 and 12, respectively, and the change in contact angle was recorded every 6 hours. After 48 hours, the water contact angle of the superhydrophobic silicon carbide membrane was still greater than 147°, and the hexadecane contact angle was still greater than 146°. This indicates that the superhydrophobic membrane prepared by the present invention has good acid and alkali resistance and good chemical stability.

[0090] Example 5

[0091] a) The silicon carbide film was oxidized at 850℃ for 3 hours. After the oxidation was completed, it was cooled to room temperature and then placed in water and ethanol for ultrasonic cleaning for 5 minutes each. After cleaning, it was removed and dried at 60℃ to obtain the oxidized silicon carbide film.

[0092] b) First, mix 100nm and 1μm titanium dioxide particles at a mass ratio of 1:1 to obtain micro-nano blended particles. Then, add the micro-nano blended particles and (3-aminopropyl)triethoxysilane to ethanol and stir at 600 rpm for 30 minutes to mix evenly and obtain a suspension. The mass ratio of micro-nano blended particles to (3-aminopropyl)triethoxysilane is 1:5, and the mass ratio of micro-nano blended particles to ethanol is 1:30.

[0093] c) Add 1g of 1H,1H,2H,2H-perfluorododecyltrimethoxysilane and 1g of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane to ethanol, and stir at 600 rpm for 30 minutes to mix evenly to obtain an impregnation solution. The total mass ratio of 1g of 1H,1H,2H,2H-perfluorododecyltrimethoxysilane to 1g of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane to ethanol is 1:100.

[0094] d) The suspension was sprayed onto the surface of the oxidized silicon carbide film using a spray gun with an inner diameter of 10 μm. The spraying pressure was 0.7 MPa and the spraying distance was 15 cm. The film was then heat-cured at 60 °C for 30 minutes to obtain the modified silicon carbide film.

[0095] e) The modified silicon carbide film is immersed in the impregnation solution for graft modification for 3 hours, then removed and heat-cured at 60°C for 30 minutes to obtain a superhydrophobic silicon carbide film.

[0096] The superhydrophobic properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0097] The water contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of water. The results showed that the water contact angle was 153.3° and the roll-off angle was 6.2°. The oil contact angle and roll-off angle of the superhydrophobic silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil, and mineral oil, respectively. The results showed that the contact angles were 152.0°, 151.4°, 152.1°, and 152.4°, respectively, and the roll-off angles were 7.8°, 6.5°, 6.7°, and 7.3°, respectively. This indicates that the superhydrophobic silicon carbide film prepared in this example has excellent superhydrophobic properties.

[0098] The self-cleaning properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0099] The superhydrophobic silicon carbide membrane was tilted at 10° and placed on a petri dish. A layer of fine sand with a particle size of 10 μm was spread on the surface. About 2 mL of water was dropped onto the top of the membrane using a micropipette. The water droplet could easily roll and carry away the fine sand on the surface of the superhydrophobic membrane. This shows that the superhydrophobic silicon carbide membrane prepared in this example has good self-cleaning properties.

[0100] The acid and alkali resistance properties of the superhydrophobic silicon carbide film prepared in this embodiment were tested:

[0101] The superhydrophobic silicon carbide membrane was immersed in solutions with pH values ​​of 1 and 12, respectively. The change in contact angle was recorded every 6 hours. After 48 hours, the water contact angle of the superhydrophobic silicon carbide membrane was still greater than 147°, and the hexadecane contact angle was still greater than 145°. The contact angle did not decrease significantly. This indicates that the superhydrophobic membrane prepared by the present invention has good acid and alkali resistance and good chemical stability.

[0102] Comparative Example 1

[0103] a) The silicon carbide film was oxidized at 850℃ for 3 hours. After the oxidation was completed, it was cooled to room temperature and then placed in water and ethanol for ultrasonic cleaning for 5 minutes each. After cleaning, it was removed and dried at 60℃ to obtain the oxidized silicon carbide film.

[0104] b) Add 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol and stir at 300 rpm for 30 minutes to mix evenly to obtain an impregnation solution, wherein the mass ratio of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol is 1:50.

[0105] c) The oxidized silicon carbide film was immersed in the immersion solution for graft modification for 1 hour, then removed and heat-cured at 60°C for 30 minutes to obtain the comparative silicon carbide film.

[0106] The difference between this comparative example and Example 1 is that the silicon carbide film after oxidation treatment was not sprayed to construct a rough surface structure, but was directly immersed in a low surface energy material solution to obtain a bihydrophobic surface.

[0107] The water contact angle and roll-off angle of the comparative silicon carbide film surface were measured using 5 μL of water. The results showed that the water contact angle was 140.3° and the roll-off angle was 50.2°. The oil contact angle and roll-off angle of the comparative silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil, and mineral oil, respectively. The results showed that the contact angles were 121.0°, 124.3°, 122.7°, and 122.4°, respectively, and the roll-off angles were 78.0°, 79.1°, 76.7°, and 76.5°, respectively. The contact angles were all less than 150° and the roll-off angles were all greater than 10°, indicating that the comparative silicon carbide film prepared in this comparative example does not possess superhydrophobicity.

[0108] The superhydrophobic silicon carbide membranes were tilted at 10° on a petri dish, and a layer of fine sand with a particle size of 10 μm was spread on the surface. A drop of water with a volume of about 2 mL was dropped onto the top of the membrane using a micropipette. The water droplet could not roll spontaneously and carry away the fine sand on the surface of the superhydrophobic membrane, indicating that the comparative silicon carbide membrane prepared in this comparative example does not have self-cleaning properties.

[0109] As can be seen from Example 1 and Comparative Example 1, under the same low surface energy material solution immersion conditions, the superhydrophobic silicon carbide film prepared by particle blending spraying and grafting process has a higher water and oil contact angle, a lower water and oil roll-off angle, and a better self-cleaning function than the comparative silicon carbide film prepared by the single immersion method.

[0110] Comparative Example 2

[0111] a) The silicon carbide film was oxidized at 850℃ for 3 hours. After the oxidation was completed, it was cooled to room temperature and then placed in water and ethanol for ultrasonic cleaning for 5 minutes each. After cleaning, it was removed and dried at 60℃ to obtain the oxidized silicon carbide film.

[0112] b) First, mix 500nm silica nanoparticles and 2μm silica microparticles at a mass ratio of 1:1 to obtain micro-nano blended particles. Then, add the micro-nano blended particles, (3-aminopropyl)triethoxysilane, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol and stir at 300 rpm for 30 minutes to mix evenly and obtain a suspension. The mass ratio of micro-nano blended particles to (3-aminopropyl)triethoxysilane to 1H,1H,2H,2H-perfluorodecyltriethoxysilane is 1:1:1, and the total mass ratio of micro-nano blended particles + (3-aminopropyl)triethoxysilane + 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol is 1:10.

[0113] c) The suspension was sprayed onto the surface of the oxidized silicon carbide film using a spray gun with an inner diameter of 10 μm. The spraying pressure was 0.2 MPa and the spraying distance was 10 cm. The film was then heat-cured at 60 °C for 30 minutes to obtain a comparative silicon carbide film.

[0114] The difference between this comparative example and Example 1 is that: micro-nano particles treated with low surface energy are directly sprayed onto the silicon carbide film surface in one step to obtain a bihydrophobic surface.

[0115] The water contact angle and roll-off angle of the comparative silicon carbide film surface were measured using 5 μL of water. The results showed that the water contact angle was 141.2° and the roll-off angle was 10.2°. The oil contact angle and roll-off angle of the comparative silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil, and mineral oil, respectively. The results showed that the contact angles were 123.3°, 125.2°, 124.7°, and 124.5°, respectively, and the roll-off angles were 18.0°, 17.3°, 16.7°, and 16.4°, respectively. The contact angles were all less than 150° and the roll-off angles were all greater than 10°, indicating that the comparative silicon carbide film prepared in this comparative example does not possess superhydrophobicity.

[0116] The superhydrophobic silicon carbide membranes were tilted at 10° on a petri dish, and a layer of fine sand with a particle size of 10 μm was spread on the surface. A drop of water with a volume of about 2 mL was dropped onto the top of the membrane using a micropipette. The water droplet could not roll spontaneously and carry away the fine sand on the surface of the superhydrophobic membrane, indicating that the comparative silicon carbide membrane prepared in this comparative example does not have self-cleaning properties.

[0117] As can be seen from Example 1 and Comparative Example 2, under the same spraying conditions, the superhydrophobic silicon carbide film prepared by particle blending spraying and grafting process has a higher water and oil contact angle, a lower water and oil roll-off angle, and a better self-cleaning function than the comparative silicon carbide film prepared by one-step spraying method.

[0118] Comparative Example 3

[0119] a) The silicon carbide film was oxidized at 850℃ for 3 hours. After the oxidation was completed, it was cooled to room temperature and then placed in water and ethanol for ultrasonic cleaning for 5 minutes each. After cleaning, it was removed and dried at 60℃ to obtain the oxidized silicon carbide film.

[0120] b) First, mix 500nm silica nanoparticles and 2μm silica microparticles at a mass ratio of 1:1 to obtain micro-nano blended particles. Then, add the micro-nano blended particles to ethanol and stir at 300 rpm for 30 minutes to mix them evenly and obtain a suspension. The mass ratio of micro-nano blended particles to ethanol is 1:10.

[0121] c) Add 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol and stir at 300 rpm for 30 minutes to mix evenly to obtain an impregnation solution, wherein the mass ratio of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol is 1:50.

[0122] d) The suspension was sprayed onto the surface of the oxidized silicon carbide film using a spray gun with an inner diameter of 10 μm. The spraying pressure was 0.2 MPa and the spraying distance was 10 cm. The film was then heat-cured at 60 °C for 30 minutes to obtain the comparative modified silicon carbide film.

[0123] e) The modified silicon carbide film was immersed in the impregnation solution for graft modification for 1 hour, then removed and heat-cured at 60°C for 30 minutes to obtain the comparative superhydrophobic silicon carbide film.

[0124] The difference between this comparative example and Example 1 is as follows:

[0125] In step (b), the suspension does not contain (3-aminopropyl)triethoxysilane, and after spraying, it is directly cured to coat the micro-nano particles onto the surface of the silicon carbide film.

[0126] The water contact angle and roll-off angle of the comparative superhydrophobic silicon carbide film surface were measured using 5 μL of water. The results were: water contact angle of 152.3° and roll-off angle of 5.6°. The oil contact angle and roll-off angle of the comparative superhydrophobic silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil, and mineral oil, respectively. The results were: 151.2°, 151.9°, 151.2°, and 151.0°, with roll-off angles of 8.0°, 8.2°, 8.0°, and 8.5°, respectively. This indicates that the comparative superhydrophobic silicon carbide film prepared in this comparative example possesses superhydrophobic properties.

[0127] The superhydrophobic silicon carbide membranes were immersed in solutions with pH values ​​of 1 and 12, and the changes in contact angle were recorded every 6 hours. After 48 hours, the shedding of micro and nanoparticles was observed in the solution. The water contact angle was measured to be 123.5° and the hexadecane contact angle was 120.4°, showing a significant decrease in contact angle.

[0128] As can be seen from Example 1 and Comparative Example 3, under the same particle blending spraying and grafting process conditions, the superhydrophobic silicon carbide film prepared with the addition of silane coupling agent is more resistant to acids and alkalis, has a stronger coating, and better chemical stability than the film prepared without the addition of silane coupling agent.

[0129] Comparative Example 4

[0130] a) The silicon carbide film was placed in water and ethanol respectively for ultrasonic cleaning for 5 minutes each, then removed and dried at 60°C to obtain the cleaned silicon carbide film.

[0131] b) First, mix 500nm silica nanoparticles and 2μm silica microparticles at a mass ratio of 1:1 to obtain micro-nano blended particles. Then, add the micro-nano blended particles and (3-aminopropyl)triethoxysilane to ethanol and stir at 300 rpm for 30 minutes to mix evenly and obtain a suspension. The mass ratio of micro-nano blended particles to (3-aminopropyl)triethoxysilane is 1:1, and the mass ratio of micro-nano blended particles to ethanol is 1:10.

[0132] c) Add 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol and stir at 300 rpm for 30 minutes to mix evenly to obtain an impregnation solution, wherein the mass ratio of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to ethanol is 1:50.

[0133] d) The suspension was sprayed onto the cleaned silicon carbide film surface using a spray gun with an inner diameter of 10 μm. The spraying pressure was 0.2 MPa and the spraying distance was 10 cm. The film was then heat-cured at 60 °C for 30 minutes to obtain a comparative modified silicon carbide film.

[0134] e) The modified silicon carbide film was immersed in the impregnation solution for graft modification for 1 hour, then removed and heat-cured at 60°C for 30 minutes to obtain the comparative silicon carbide film.

[0135] The difference between this comparative example and Example 1 is as follows:

[0136] A bihydrophobic surface was obtained by directly spraying and impregnating an unoxidized silicon carbide film.

[0137] The water contact angle and roll-off angle of the comparative silicon carbide film surface were measured using 5 μL of water. The results showed that the water contact angle was 144.5° and the roll-off angle was 15.2°. The oil contact angle and roll-off angle of the comparative silicon carbide film surface were measured using 5 μL of hexadecane, rapeseed oil, olive oil, and mineral oil, respectively. The results showed that the contact angles were 133.3°, 134.2°, 134.7°, and 135.5°, respectively, and the roll-off angles were 17.2°, 17.3°, 18.7°, and 17.4°, respectively. The contact angles were all less than 150° and the roll-off angles were all greater than 10°, indicating that the comparative silicon carbide film prepared in this comparative example does not possess superhydrophobicity.

[0138] As can be seen from Example 1 and Comparative Example 4, under the same particle blending spraying and grafting process conditions, the superhydrophobic silicon carbide film prepared with the oxidized silicon carbide film as the substrate has a higher water and oil contact angle and a lower water and oil roll-off angle than the comparative silicon carbide film prepared with the unoxidized silicon carbide film as the substrate.

[0139] Finally, it should be noted that the above are only some preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a superhydrophobic silicon carbide film with self-cleaning function, characterized in that: Includes the following steps: a) The silicon carbide film is oxidized to obtain an oxidized silicon carbide film; b) First, mix nanoparticles and microparticles of different sizes to obtain micro-nano blended particles. Then, add the micro-nano blended particles and silane coupling agent to ethanol and stir to mix them evenly to obtain a suspension. The microparticles and nanoparticles are selected from any one of silicon dioxide, aluminum oxide, and titanium dioxide. c) Add the fluorine-containing low surface energy material to ethanol and stir to mix evenly to obtain the impregnation solution; the fluorine-containing low surface energy material is a fluorosilane coupling agent; d) The suspension is sprayed onto the surface of the oxidized silicon carbide film and then thermally cured at 55-65°C for 15-45 minutes to obtain a modified silicon carbide film; e) The modified silicon carbide film is immersed in the impregnation solution for graft modification, taken out, and heat-cured at 55-65℃ for 15-45 minutes to obtain a superhydrophobic silicon carbide film.

2. The preparation method according to claim 1, characterized in that: In step a), the silicon carbide film undergoes an oxidation treatment, the specific operation of which is as follows: The silicon carbide film was oxidized at 800-900℃ for 2-4 hours. After oxidation, it was cooled to room temperature and then ultrasonically cleaned in water and ethanol for 3-10 minutes respectively. After cleaning, it was dried at 55-65℃ to obtain the oxidized silicon carbide film.

3. The preparation method according to claim 1, characterized in that: In step b), nanoparticles and microparticles are mixed at a mass ratio of 1:(0.5 to 3).

4. The preparation method according to claim 1, characterized in that: In step b), the silane coupling agent is at least one of (3-aminopropyl)triethoxysilane, bis(3-trimethoxysilylpropyl)amine, and diethoxydimethoxysilane.

5. The preparation method according to claim 1, characterized in that: In step b), the mass ratio of micro / nano blended particles to silane coupling agent is 1:(1-5); the mass ratio of micro / nano blended particles to ethanol is 1:(10-30).

6. The preparation method according to claim 1, characterized in that: In step c), the fluorosilane coupling agent is at least one of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, and 1H,1H,2H,2H-perfluorododecyltrimethoxysilane.

7. The preparation method according to claim 1, characterized in that: In step c), the mass ratio of fluorine-containing low surface energy substance to ethanol is 1:(50-100).

8. The preparation method according to claim 1, characterized in that: In step d), the suspension is sprayed onto the surface of the oxidized silicon carbide film using a spray gun. The spraying pressure is 0.2 to 0.7 MPa and the spraying distance is 10 to 15 cm.

9. The preparation method according to claim 1, characterized in that: In step e), the modified silicon carbide film is immersed in the impregnation solution for graft modification for 1 to 3 hours.

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