Collaborative resistance-reducing bionic composite structure based on underwater vehicle and preparation process of collaborative resistance-reducing bionic composite structure

Abstract

The invention discloses a collaborative anti-drag bionic composite structure based on an underwater vehicle and a preparation process thereof, and belongs to the technical field of ship and ocean engineering. A downstream structure is constructed on the surface of the vehicle, a microstructure is constructed in the structure, and the downstream structure is subjected to surface modification to form a lubricating layer; the turbulent flow generation position is changed through the downstream structure, near-wall-surface speed slippage is achieved through the lubricating layer, the speed gradient and the turbulent flow intensity are reduced, and then collaborative resistance reduction is achieved. According to the method, different preparation technologies can be selected according to different materials, and when the materials are aluminum alloy, the micro-nano coating on the surface of the composite structure is prepared in a hydrochloric acid etching and ultrasonic treatment mode; when the material is stainless steel, the micro-nano coating on the surface of the composite structure is prepared in an electroplating treatment mode, and finally the synergistic resistance reduction bionic composite structure which is kept stable within the flow speed range of 2 m / s to 6 m / s and of which the resistance coefficient is reduced by 11% to 24% is obtained.

Description

Technical Field

[0001] This invention belongs to the technical field of shipbuilding and marine engineering, specifically relating to a biomimetic composite structure for collaborative drag reduction of underwater vehicles and its fabrication process. Background Technology

[0002] With the rapid development of marine technology, underwater vehicles are playing an increasingly important role in key areas such as deep-sea exploration, resource exploration, and national defense. Their speed and range are directly constrained by fluid resistance. Especially at high speeds or in complex sea conditions, the strong interaction between the surface and the water flow not only significantly increases energy consumption but also easily triggers gas-liquid interface instability, leading to a decline in drag reduction performance. Therefore, how to reduce fluid resistance while maintaining the dynamic stability of the air cushion layer has become one of the core challenges in improving the overall performance of underwater vehicles.

[0003] Biomimetic surface structure design is considered a crucial pathway to achieving efficient drag reduction. By mimicking the micro-nano composite structures of organisms such as shark skin and dolphin skin, the velocity gradient distribution in the near-wall region can be controlled, suppressing turbulence generation and thus reducing shear stress. However, existing biomimetic drag reduction technologies mostly focus on static structural optimization, making it difficult to adapt to dynamic requirements under different speeds and flow field conditions, and lacking a systematic and coordinated design for the formation and maintenance mechanisms of the air cushion layer. Therefore, there is an urgent need for a biomimetic composite structure design technology that can synergistically optimize air cushion stability and fluid resistance to overcome the multiple bottlenecks in energy efficiency, adaptability, and reliability of existing underwater drag reduction solutions. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a biomimetic composite structure for collaborative drag reduction of underwater vehicles and its manufacturing process to solve the problems mentioned in the background art or achieve better technical effects.

[0005] To solve the above-mentioned technical problems, the inventors derived the technical solution of the present invention through practice and summarization. The present invention discloses a biomimetic composite structure for collaborative drag reduction of underwater vehicles, including a component body. The component body has several sets of horizontally oriented downstream semicircular structures. Inside the downstream semicircular structures, several sets of vertically arranged and parallel built-in rectangular structures are formed. The surfaces of the downstream semicircular structures and the built-in rectangular structures are all coated with micro-nano coatings.

[0006] The size of the micro / nano coating is 10 nm to 10 μm;

[0007] The micro / nano coating is prepared by etching with hydrochloric acid and ultrasonic treatment on the surface of the co-current semi-circular structure and the built-in rectangular structure, followed by hydroxylation treatment and immersion in stearic acid solution; or by electroplating to prepare the micro / nano structure on the surface of the co-current semi-circular structure and the built-in rectangular structure, followed by hydroxylation treatment and immersion in ethanol solution of 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane.

[0008] Furthermore, the spacing between adjacent downstream semicircular structures is 0.02 mm, and the spacing between adjacent built-in rectangular structures is 0.02 mm.

[0009] Furthermore, the width of the downstream semi-circular structure 1 is 0.5~1mm; the width of the built-in rectangular structure is 0.3~0.8mm, and the aspect ratio is 1.

[0010] Furthermore, the fabrication process of any of the above-mentioned biomimetic composite structures based on collaborative drag reduction for underwater vehicles includes the following steps:

[0011] S1: Several sets of downstream semi-circular structures were prepared on the surface of the sample by mechanical processing;

[0012] S2: Several sets of built-in rectangular structures with a depth-to-width ratio of 1 are prepared by mechanical processing within the downstream semicircular structure. The spacing between the built-in rectangular structures is 0.02 mm, and the several sets of built-in rectangular structures are distributed along the downstream semicircular structure to obtain a biomimetic structure.

[0013] S3: Depending on the material of the composite structure, hydrochloric acid etching + ultrasonic treatment or electroplating is used to construct micro-nano structures on the surface of the biomimetic structure obtained in S2 to obtain the composite structure.

[0014] S4: The composite structure obtained in S3 is subjected to hydroxylation treatment, followed by cleaning and drying to obtain the modified sample;

[0015] S5: Immerse the modified sample obtained in S4 in a stearic acid solution or an ethanol solution of 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane to obtain a synergistic drag-reducing biomimetic composite structure with different wettability surfaces.

[0016] Furthermore, in S3, when the composite structure material is aluminum alloy, a micro-nano structure is constructed on the surface of the biomimetic structure by hydrochloric acid etching and ultrasonic treatment; when the composite structure material is stainless steel, a micro-nano structure is constructed on the surface of the biomimetic structure by electroplating.

[0017] Furthermore, when the composite structure is made of aluminum alloy, the method for constructing micro-nano structures on the surface of the biomimetic structure using hydrochloric acid etching combined with ultrasonic treatment is as follows:

[0018] The biomimetic structure obtained in S2 was first immersed in hydrochloric acid aqueous solution and treated with 40kHz ultrasound. Then it was taken out, cleaned, and dried to obtain a composite structure with micro-nano structures on the surface.

[0019] Furthermore, when the composite structure is made of stainless steel, the method for constructing the micro / nano structure on the surface of the biomimetic structure using electroplating is as follows:

[0020] The biomimetic structure obtained from S2 was electroplated with a current density of 1~3 A / dm³. 2 The pH of the electroplating solution was gradually adjusted to 8.0~10.0 using ammonia water; the temperature of the electroplating solution was adjusted to 60℃ using temperature control, and the deposition time was 10 min, resulting in an electroplated composite structure with a surface micro-nano coating thickness of 10 μm.

[0021] Furthermore, the concentration of the hydrochloric acid aqueous solution is 10%; the ultrasonic treatment time is 20 minutes.

[0022] Furthermore, the components of the electroplating solution include: 25 g / L NiSO4·6H2O, 30 g / L NaH2PO2·H2O, 15 g / L complexing agent, 9 g / L sodium acetate, and 0.005 g / L thiourea;

[0023] The complexing agent is sodium citrate.

[0024] Furthermore, in step S5, the concentration of the stearic acid solution is 0.5%, the temperature is 60°C, the concentration of the ethanol solution of 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane is 1%, and the soaking time is 2-7 hours.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) The present invention constructs a flow-direction structure on the surface of the vehicle and constructs a microstructure within the structure. The flow-direction structure is surface modified to form a "lubricating layer". The flow-direction structure changes the location of turbulence and the "lubricating layer" enables near-wall velocity slippage, reducing the velocity gradient and turbulence intensity, thereby achieving synergistic drag reduction.

[0027] (2) The synergistic drag reduction biomimetic composite structure of the present invention can be prepared by different preparation techniques depending on the material. When the material is aluminum alloy, hydrochloric acid etching + ultrasonic treatment is used to prepare the micro-nano coating on the surface of the composite structure. When the material is stainless steel, electroplating + 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane treatment is used to prepare the micro-nano coating on the surface of the composite structure. Finally, a synergistic drag reduction biomimetic composite structure that remains stable in the flow velocity range of 2m / s to 6m / s and has a drag coefficient reduced by 11% to 24% is obtained.

[0028] (3) In the hydrochloric acid etching process of this invention, the composite structure with surface-loaded micro / nano coatings obtained by hydrochloric acid etching is subjected to surface hydroxylation treatment to obtain a modified sample. Then, the modified sample is immersed in stearic acid solution to obtain a synergistic drag-reducing biomimetic composite structure with different wettability surfaces. By hydroxylating the composite structure with surface-loaded micro / nano coatings, the coating surface is hydroxylated. Stearic acid has carboxyl groups in aqueous solution. The hydroxyl groups on the surface react chemically with the carboxyl groups of stearic acid, making it easier for stearic acid to be grafted onto the surface of the composite structure. Stearic acid is a low surface energy material. Grafting it onto the surface of the composite structure can reduce the wettability of the structure to water.

[0029] (4) The synergistic drag reduction biomimetic composite structure prepared by the present invention also has a surface self-cleaning function. Through the low adhesion characteristics of the superhydrophobic surface, the amount of marine organisms attached is reduced by more than 90%, the resistance increase caused by surface pollution is less than 5%, and the cleaning cycle is extended to more than 3 times that of traditional surfaces. Attached Figure Description

[0030] Figure 1 This is a three-dimensional schematic diagram of the biomimetic composite structure for collaborative drag reduction of underwater vehicles based on the present invention;

[0031] Figure 2 This is a graph showing the relationship between wettability and immersion time after the surface and interface modification of the biomimetic composite structure for collaborative drag reduction of underwater vehicles according to the present invention.

[0032] Figure 3 The diagram shows the drag reduction rate and contact angle of the composite structure obtained by different modifications (electroplation and hydrochloric acid etching) according to the present invention.

[0033] Figure 4 This is a graph showing the relationship between drag reduction rate and flow rate of the composite structure obtained by different modifications (electroplation and hydrochloric acid etching) in this invention.

[0034] Figure 5 This is a cloud diagram illustrating the collaborative drag reduction principle of the biomimetic composite structure for collaborative drag reduction of underwater vehicles, as presented in this invention.

[0035] Where a is the velocity contour distribution after drag reduction failure; b is the velocity distribution of the cooperative drag reduction;

[0036] Figure 6 The contact angle of the built-in structure surface after hydrochloric acid etching modification is 155°.

[0037] Figure 7 The contact angle of the semi-circular structure surface modified by hydrochloric acid etching in the downstream direction of the present invention is 155°.

[0038] Figure 8The contact angle after electroplating modification of the surface of the built-in structure of this invention is 161°;

[0039] Figure 9 The contact angle of the semi-circular structure surface after electroplating modification in the downstream direction of the present invention is 161°.

[0040] Figure 10 This is a SEM image of a portion of the composite structure after hydrochloric acid etching according to the present invention.

[0041] Figure 11 This is a partial SEM image of the composite structure after electroplating according to the present invention.

[0042] Figure label:

[0043] 1. Flow-oriented semi-circular structure; 2. Spacing between flow-oriented semi-circular structures; 3. Built-in rectangular structure; 4. Spacing between built-in rectangular structures. Detailed Implementation

[0044] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0045] Unless otherwise specified, all raw materials or reagents used in the following examples are commercially available products.

[0046] Example 1

[0047] like Figure 1 As shown, a biomimetic composite structure for collaborative drag reduction of underwater vehicles includes a component body. Several sets of downstream semicircular structures 1 are parallelly formed on the component body, and the spacing 2 between adjacent downstream semicircular structures 1 is 0.02 mm. Several sets of parallel-arranged built-in rectangular structures 3 are formed inside the downstream semicircular structures 1, and the spacing 4 between the built-in rectangular structures is 0.02 mm.

[0048] Preferably, the width of the adjacent downstream semicircular structure 1 is 0.5~1mm;

[0049] Preferably, the width of the built-in rectangular structure 3 is set to 0.3~0.8mm according to the actual flow rate, and the aspect ratio of the built-in rectangular structure 3 is 1;

[0050] The surface of the entire synergistic drag-reducing biomimetic composite structure is constructed with micro- and nano-structures.

[0051] Example 2

[0052] When the sample material used is aluminum alloy, the preparation process of the above-mentioned biomimetic composite structure based on underwater vehicle drag reduction is as follows:

[0053] (1) Several sets of semi-circular structures 1 with a radius of 0.5 mm were prepared on the surface of the aluminum alloy sample by mechanical processing, and the spacing 2 between adjacent semi-circular structures 1 was 0.02 mm.

[0054] (2) Several sets of built-in rectangular structures 3 with a depth-to-width ratio of 1 are prepared in the semi-circular structure 1 along the flow direction by mechanical processing. The spacing 4 between the built-in rectangular structures is 0.02 mm, and the several sets of built-in rectangular structures 3 are distributed along the semi-circular structure 1 along the flow direction to obtain a biomimetic structure.

[0055] (3) Constructing micro-nano structures on the surface of the biomimetic structure prepared in step (2): Using the hydrochloric acid etching method, the biomimetic structure sample was first immersed in a 10% hydrochloric acid aqueous solution, ultrasonically treated at 40 kHz for 20 min, then taken out, cleaned, and dried to obtain a composite structure with a micro-nano coating on the surface, the surface morphology of which is as follows. Figure 10 As shown, micro- and nano-structures are constructed within the composite structure to increase capillary forces on air and enhance the hydrophobic, oleophilic, or air-dependent properties of the composite structure.

[0056] (4) The composite structure of surface-loaded micro-nano coating obtained in step (3) is placed in a 5% sodium hydroxide solution at 50°C for hydroxylation treatment. After 6 hours of reaction, it is taken out, cleaned and dried to obtain the modified sample.

[0057] (5) The modified sample obtained in step (4) is immersed in a 0.5% stearic acid solution at 60°C for 2-7 hours to obtain a synergistic drag-reducing biomimetic composite structure with different wettability surfaces. By hydroxylating the composite structure with micro-nano coatings on the surface, the coating surface is hydroxylated. Stearic acid has carboxyl groups in aqueous solution. The hydroxyl groups on the surface react chemically with the carboxyl groups of stearic acid, making it easier for stearic acid to be grafted onto the surface of the composite structure. Stearic acid is a low surface energy material. Grafting it onto the surface of the composite structure can reduce the wettability of the structure to water.

[0058] As the immersion time increases, the wettability of this synergistic drag-reducing biomimetic composite structure decreases as... Figure 2 As shown; the contact angle of the built-in structure surface after hydrochloric acid etching modification is as follows. Figure 6 As shown; the contact angle of the semi-circular structure surface modified by hydrochloric acid etching in the direction of flow is as follows. Figure 7 As shown.

[0059] Example 3

[0060] When the sample material used is stainless steel, the preparation process of the above-mentioned biomimetic composite structure based on underwater vehicle drag reduction is as follows:

[0061] (1) Several sets of semi-circular structures 1 with a radius of 0.5 mm were prepared on the surface of the stainless steel sample by mechanical processing, and the spacing 2 between adjacent semi-circular structures 1 was 0.02 mm.

[0062] (2) Several sets of built-in rectangular structures 3 with a depth-to-width ratio of 1 are prepared in the semi-circular structure 1 along the flow direction by mechanical processing. The spacing 4 between the built-in rectangular structures is 0.02 mm, and the several sets of built-in rectangular structures 3 are distributed along the semi-circular structure 1 along the flow direction to obtain a biomimetic structure.

[0063] (3) Preparation of micro / nano coatings on the biomimetic structure surface prepared in step (2): Micro / nano structures are constructed on the biomimetic structure surface by electroplating with a current density of 1~3 A / dm 2 The pH of the electroplating solution was gradually adjusted to 8.0–10.0 using ammonia water; the temperature of the electroplating solution was controlled at 60℃, and the deposition time was 10 min, resulting in an electroplating composite structure with a surface micro / nano coating thickness of 10 μm. The micro / nano morphology of the surface micro / nano coating of this electroplating composite structure is as follows: Figure 11 As shown;

[0064] The electroplating solution consists of: nickel sulfate (NiSO4·6H2O) 25g / L, sodium hypophosphite (NaH2PO2·H2O) 30g / L, complexing agent 15g / L, sodium acetate 9g / L, and thiourea 0.005g / L; the complexing agent is sodium citrate.

[0065] (4) The electroplated composite structure prepared in step (3) was placed in a 5% sodium hydroxide solution at 50°C for hydroxylation treatment. After reacting for 6 hours, it was taken out, cleaned, and dried to obtain the modified sample.

[0066] (5) The modified sample from step (4) is immersed in an ethanol solution of 1% 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane at room temperature for 2-7 hours to obtain a synergistic drag-reducing biomimetic composite structure with different wettability surfaces. Hydroxylation treatment is used to hydroxylate the surface of the electroplated composite structure, while the ethanol solution of 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane undergoes hydrolysis. After hydrolysis, each 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane carries three carboxyl groups. The hydroxyl groups on the sample surface react chemically with the carboxyl groups on the hydrolyzed 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane, thereby grafting 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane onto the surface of the composite structure. Grafting 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane onto the surface of the composite structure reduces the wettability of the composite structure to water.

[0067] As the immersion time increases, the wettability of this synergistic drag-reducing biomimetic composite structure decreases as... Figure 2As shown; the contact angle of the built-in structure surface after electroplating modification is shown in Figure 8; the contact angle of the semi-circular structure surface after electroplating modification in the downstream direction is shown in Figure 9. Figure 9 As shown.

[0068] Example 4

[0069] The synergistic drag-reducing biomimetic composite structures prepared in Examples 2 and 3 were subjected to water tunnel tests (the flow medium was water, the flow velocity in the water tunnel was 1~7 m / s, and the density was 998.82 Kg / m³). 3 The lubricating medium is air, and the resistance is tested from 0 to 50 N with a test accuracy of 0.001 N. The test method is as follows: The synergistic drag reduction biomimetic composite structure is placed in a water tunnel, and the stability and resistance of the lubricating medium are tested and observed by adjusting different flow rates to obtain the stability and synergistic drag reduction rate of the lubricating medium under different sizes and morphologies.

[0070] like Figure 3 As shown, at a flow velocity of 6 m / s, with the increase of the contact angle, the wettability of the air on the structure increases, and the turbulence generates a reverse secondary vortex in the downstream direction towards the top of the structure, such as... Figure 5 As shown in (b), the maximum drag reduction rate is 24%.

[0071] The effect of different flow velocities on drag reduction ratio is as follows: Figure 4 As shown, with increasing flow velocity, the drag reduction ratios of the composite structures obtained by both modification methods initially increase and then decrease. This is because the velocity slip of the rectangular structure reduces the blockage of the flow field in the downstream direction, leading to an upward shift of the turbulent shear stress in the wide structure. Figure 5 As shown in (b), when the flow velocity is higher than 6 m / s, the partial escape of air from the lubricating medium leads to a decrease in slip velocity, and the turbulent shear stress gradually shifts downward, as... Figure 5 As shown in (a), this results in a decrease in drag reduction rate.

[0072] Therefore, the synergistic drag reduction biomimetic composite lubrication layer prepared by the present invention remains stable in the flow velocity range of 2~6m / s, and the drag coefficient is reduced by 11~24%.

Claims

1. A biomimetic composite structure for collaborative drag reduction of underwater vehicles, characterized in that, The component body includes a number of horizontally oriented semi-circular structures (1) with a flow direction. The semi-circular structures (1) with a flow direction have a number of vertically arranged and parallel internal rectangular structures (3) inside. The surfaces of the semi-circular structures (1) with a flow direction and the internal rectangular structures (3) are coated with micro-nano coatings. The size of the micro / nano coating is 10 nm to 10 μm; The micro / nano coating is prepared on the surface of the co-current semi-circular structure (1) and the built-in rectangular structure (3) by hydrochloric acid etching and ultrasonic treatment, followed by hydroxylation treatment and immersion in stearic acid solution; or the micro / nano structure is prepared on the surface of the co-current semi-circular structure (1) and the built-in rectangular structure (3) by electroplating, followed by hydroxylation treatment and immersion in ethanol solution of 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane.

2. The biomimetic composite structure for collaborative drag reduction of underwater vehicles according to claim 1, characterized in that, The spacing (2) between adjacent downstream semicircular structures (1) is 0.02 mm, and the spacing (4) between adjacent built-in rectangular structures (3) is 0.02 mm.

3. The biomimetic composite structure for collaborative drag reduction of underwater vehicles according to claim 1, characterized in that, The width of the downstream semicircular structure 1 is 0.5~1mm; the width of the built-in rectangular structure (3) is 0.3~0.8mm, and the depth-to-width ratio is 1.

4. A fabrication process for a biomimetic composite structure based on collaborative drag reduction for underwater vehicles as described in any one of claims 1 to 3, characterized in that, The steps are as follows: S1: Several sets of downstream semi-circular structures were prepared on the surface of the sample by mechanical processing (1). S2: Several sets of built-in rectangular structures (3) with a depth-to-width ratio of 1 are prepared in the semi-circular structure (1) in the direction of the flow by mechanical processing. The spacing (4) between the built-in rectangular structures is 0.02 mm. Several sets of built-in rectangular structures (3) are distributed along the semi-circular structure (1) in the direction of the flow to obtain a biomimetic structure. S3: Depending on the material of the composite structure, hydrochloric acid etching + ultrasonic treatment or electroplating is used to construct micro-nano structures on the surface of the biomimetic structure obtained in S2 to obtain the composite structure. S4: The composite structure obtained in S3 is subjected to hydroxylation treatment, followed by cleaning and drying to obtain the modified sample; S5: Immerse the modified sample obtained in S4 in a stearic acid solution or an ethanol solution of 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane to obtain a synergistic drag-reducing biomimetic composite structure with different wettability surfaces.

5. The fabrication process of the biomimetic composite structure for collaborative drag reduction of underwater vehicles according to claim 4, characterized in that, In S3, when the composite structure material is aluminum alloy, a micro-nano structure is constructed on the surface of the biomimetic structure by hydrochloric acid etching and ultrasonic treatment; when the composite structure material is stainless steel, a micro-nano structure is constructed on the surface of the biomimetic structure by electroplating.

6. The fabrication process of the biomimetic composite structure for collaborative drag reduction of underwater vehicles according to claim 5, characterized in that, When the composite structure is made of aluminum alloy, the method for constructing micro-nano structures on the surface of the biomimetic structure using hydrochloric acid etching and ultrasonic treatment is as follows: The biomimetic structure obtained in S2 was first immersed in hydrochloric acid aqueous solution and treated with 40kHz ultrasound. Then it was taken out, cleaned, and dried to obtain a composite structure with micro-nano structures on the surface.

7. The fabrication process of the biomimetic composite structure for collaborative drag reduction of underwater vehicles according to claim 5, characterized in that, When the composite structure is made of stainless steel, the method for constructing micro-nano structures on the surface of the biomimetic structure by electroplating is as follows: The biomimetic structure obtained from S2 was electroplated with a current density of 1~3 A / dm³. 2 The pH of the electroplating solution was gradually adjusted to 8.0~10.0 using ammonia water; the temperature of the electroplating solution was adjusted to 60℃ using temperature control, and the deposition time was 10 min, resulting in an electroplated composite structure with a surface micro-nano coating thickness of 10 μm.

8. The fabrication process of the biomimetic composite structure for collaborative drag reduction of underwater vehicles according to claim 6, characterized in that, The concentration of the hydrochloric acid aqueous solution was 10%; the ultrasonic treatment time was 20 minutes.

9. The fabrication process of the biomimetic composite structure for collaborative drag reduction of underwater vehicles according to claim 7, characterized in that, The electroplating solution comprises: 25 g / L NiSO4·6H2O, 30 g / L NaH2PO2·H2O, 15 g / L complexing agent, 9 g / L sodium acetate, and 0.005 g / L thiourea. The complexing agent is sodium citrate.

10. The fabrication process of the biomimetic composite structure for collaborative drag reduction of underwater vehicles according to claim 4, characterized in that, In step S5, the concentration of the stearic acid solution is 0.5%, and the temperature is 60°C; the concentration of the ethanol solution of 1H, 1H, 2H, 2H perfluorodecyltriethoxysilane is 1%; and the soaking time is 2-7 hours.

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