Method for preparing graded inverted triangular microstructure on surface of silicone rubber

Abstract

The invention relates to a method for preparing a graded inverted triangular microstructure on the surface of silicone rubber, which comprises the following steps: etching the surface of a titanium-aluminum alloy by femtosecond laser, adjusting the spot diameter, pulse width, energy density, scanning speed and scanning spacing of laser processing, and constructing the graded inverted triangular microstructure on the surface of the titanium-aluminum alloy; and copying the graded inverted triangular microstructure on the titanium-aluminum alloy template to the pretreated silicon rubber surface. The graded inverted triangular microstructure not only has the capability of improving the hydrophobic performance of the surface of the material of a conventional microstructure, but also improves the overall wear resistance of the microstructure by virtue of the specific graded structure, so that the overall weather resistance of the material is effectively improved. The process is relatively simple, the influence of experimental conditions is small, the used titanium-aluminum alloy template has considerable reuse value, and the application cost is further reduced.

Description

Technical Field

[0001] The invention relates to the technical field of material surface microstructure design, and in particular to a method for preparing a graded inverted triangle microstructure on a silicone rubber surface. Background Art

[0002] Insulators, as critical components of transmission lines, provide both electrical insulation and mechanical support. During operation, contamination accumulates on the insulator surface due to factors such as the operating environment, ultimately leading to insulator flashover accidents. Insulator flashover accidents are characterized by long duration and wide scope, and are a key factor seriously impacting the operational reliability of power systems. In recent years, numerous line tripping and system power outages caused by insulator flashover have occurred under adverse weather conditions such as dew, fog, drizzle, and snowmelt, resulting in significant damage to primary power equipment and social and economic losses.

[0003] Composite insulators are primarily composed of silicone rubber, which exhibits a certain degree of hydrophobicity and hydrophobic migration, thereby improving the insulator's water and dirt removal properties. However, existing silicone rubber surfaces typically have hydrophobic contact angles less than 110°, failing to achieve superhydrophobicity and effectively resisting water and dirt removal. This results in limited improvements in the anti-fouling properties of insulators made with silicone rubber.

[0004] Patent document CN113210872A discloses a method for rapidly preparing a biomimetic super-hydrophobic surface on a titanium alloy using a femtosecond laser. This method first forms a micro-nanostructure on the titanium alloy surface through femtosecond laser etching, and then combines it with an aging treatment to reduce the surface energy of the titanium alloy surface to achieve the preparation of a biomimetic super-hydrophobic surface on the titanium alloy. Although this method forms a dual-scale micro-nanostructure, this structure is relatively simple and lacks hierarchy and complexity, which cannot meet higher performance requirements. In addition, the high cost of the titanium alloy material itself makes the entire process expensive, limiting its large-scale application. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a method for preparing a graded inverted triangular microstructure on the surface of silicone rubber. By constructing a protruding structure on the surface of silicone rubber, the protruding structure is a graded inverted triangular structure, which can greatly improve the hydrophobicity of silicone rubber, achieve super-hydrophobicity, and have good waterproof and decontamination capabilities to solve the above problems.

[0006] The present invention provides the following technical solutions:

[0007] A method for preparing a hierarchical inverted triangle microstructure on a silicone rubber surface, the method comprising the following steps:

[0008] Step S1, preparation of a titanium-aluminum alloy template based on laser processing: etching the titanium-aluminum alloy surface by femtosecond laser, adjusting the laser processing spot diameter, pulse width, energy density, scanning speed and scanning spacing, and constructing a hierarchical inverted triangle microstructure on the titanium-aluminum alloy surface;

[0009] Step S2, template hot stamping: Template hot stamping: After pre-treating the template, the silicone rubber material is placed on the template, compressed by a heated upper pressing plate, and appropriate stamping temperature, pressure and time are set. After cooling, the silicone rubber with an inverted triangular microstructure on the surface is obtained.

[0010] Furthermore, it is characterized in that the hierarchical inverted triangle microstructure is formed by stacking three different levels of convex column arrays in sequence in the surface normal direction, and the surface contour line can be expressed by the following periodic function:

[0011]

[0012] Wherein, x is the horizontal direction of the front view of the titanium-aluminum alloy, y is the vertical direction of the front view of the titanium-aluminum alloy; the period of the function is T=50, and the unit is μm.

[0013] Furthermore, the hierarchical inverted triangle microstructure is processed on the titanium aluminum alloy surface by femtosecond laser etching, and the laser etching scanning process includes: a first laser scan, setting the laser power to 10-20mW, the repetition frequency to 500KHz, the scanning speed to 350-500mm / s, the scanning spacing to 50μm, and the number of repetitions to 2 times, to achieve the first-level structure of the inverted triangle microstructure; a second laser scan, setting the laser power to 20-30mW, the repetition frequency to 500KHz, the scanning speed to 200-350mm / s, the scanning spacing to 50μm, and the number of repetitions to 2 times, to achieve the second-level structure of the inverted triangle microstructure; a third laser scan, setting the laser power to 30-40mW, the repetition frequency to 500KHz, the scanning speed to 50-200mm / s, the scanning spacing to 50μm, and the number of repetitions to 2 times, to achieve the third-level structure of the inverted triangle microstructure.

[0014] Furthermore, the size of the titanium aluminum alloy is 30mm×30mm×1.5mm, and its composition and proportions of each component are: titanium (Ti) 46wt%, aluminum (Al) 47wt%, vanadium (V) 2.5wt%, chromium (Cr) 1.5wt%, and niobium (Nb) 3wt%.

[0015] Furthermore, the pretreatment includes: ultrasonically cleaning the titanium-aluminum alloy with a hierarchical inverted triangle microstructure formed on the surface with anhydrous ethanol and deionized water for 5-10 minutes in sequence to remove impurities generated by laser processing, and placing it in a 60°C drying oven for 10-20 minutes; soaking the titanium-aluminum alloy template in a saturated stearic acid ethanol solution for 3-5 minutes to allow the stearic acid to fully penetrate the structure.

[0016] Furthermore, the imprinting temperature is 120-150° C., the pressure is 0-25 MPa, and is maintained for 3-5 minutes.

[0017] The present invention has the following beneficial technical effects:

[0018] The hierarchical inverted triangle microstructure of this invention significantly improves the hydrophobicity of the material surface. Its unique hierarchical structure further enhances the microstructure's wear resistance and improves its weather resistance. By combining laser processing with a template method, the microstructure was successfully replicated onto the surface of silicone rubber, effectively improving its hydrophobicity and providing an effective solution to flashover accidents involving insulators in power systems.

[0019] The present invention uses hot embossing to replicate the unique structure on a titanium-aluminum alloy template onto a pretreated silicone rubber surface, resulting in a hierarchical inverted triangular micro-nanostructure. The present invention introduces a microstructure template, formed using laser etching, which achieves transfer accuracy far superior to traditional molding. Stearic acid pretreatment enhances demolding properties and reduces microstructure damage. Temperature, pressure, and time are optimized and controlled at a microscopic scale to ensure complete structural replication. The process of the present invention is relatively simple and less affected by experimental conditions. The titanium-aluminum alloy template used has considerable reusability, further reducing application costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a method for preparing a hierarchical inverted triangle microstructure on a silicone rubber surface according to the present invention;

[0021] Figure 2 This is a structural diagram of the laser processing system of the present invention;

[0022] Figure 3 This is a theoretical structural diagram of the hierarchical inverted triangle structure described in the present invention. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] The present invention proposes a method for preparing a hierarchical inverted triangle microstructure on the surface of silicone rubber. The method is divided into two parts: titanium-aluminum alloy template preparation based on laser processing and template hot embossing.

[0025] The laser processing described in the present invention adopts femtosecond laser scanning, and through multiple groups of laser scanning with different parameter settings, a graded inverted triangle microstructure is etched on the surface of the aluminum-titanium alloy.

[0026] The laser processing system of the present invention is composed of a femtosecond laser system, a laser processing optical path system, a displacement control system (a high-speed scanning polarizer and a three-dimensional high-precision moving platform), as shown in the attached Figure 2 As shown. The femtosecond laser system is responsible for outputting linearly polarized laser light, which is attenuated, filtered, and has its energy density adjusted by the laser processing optical path system before entering the scanning polarization system. After passing through the scanning polarization system, the laser processes the sample placed on a three-dimensional high-precision mobile platform. Both the three-dimensional high-precision mobile platform and the scanning polarization system are used to adjust the laser scanning pattern on the sample surface. The former controls the stage to produce relative displacement with the laser (sample moves, laser is fixed), while the latter processes the sample by controlling the laser's motion trajectory (sample is fixed, laser moves). Both are controlled by a computer program.

[0027] The ideal structure of the graded inverted triangle of the present invention is shown in the attached figure. Figure 3 As shown. The overall outline of the groove part of the graded inverted triangle structure on the template is roughly in the shape of an inverted triangle, and the convex part is formed by an array of convex columns of different areas stacked in the normal direction of the surface. This microstructure not only has the ability of conventional microstructures to improve the hydrophobicity of the material surface, but its unique graded structure also increases the wear resistance of the microstructure as a whole, effectively improving the weather resistance of the material as a whole. Using mathematical language to describe the graded inverted triangle structure, as Figure 2 As shown in , a plane rectangular coordinate system is established in the front view, and the contour line of the microstructure surface can be expressed by the following periodic function (1):

[0028]

[0029] Wherein, x is the horizontal direction of the front view of the titanium-aluminum alloy, y is the vertical direction of the front view of the titanium-aluminum alloy; the period of the function is T=50, and the unit is μm.

[0030] The hot embossing method of the present invention replicates the microstructure on the template onto the surface of the silicone rubber material by pre-treating the template and setting appropriate embossing temperature, pressure and time.

[0031] The titanium-aluminum alloy described in the present invention has a size of 30mm×30mm×1.5mm, and its composition and proportions of each component are: titanium (Ti) 46wt%, aluminum (Al) 47wt%, vanadium (V) 2.5wt%, chromium (Cr) 1.5wt%, and niobium (Nb) 3wt%.

[0032] A method for preparing a hierarchical inverted triangle microstructure on a silicone rubber surface comprises the following specific steps:

[0033] (1) Preparation of titanium-aluminum alloy template based on laser processing:

[0034] (1) Use sandpaper of different specifications in the range of 200-1000 mesh to mechanically polish the surface of the titanium aluminum alloy. The mesh number of the sandpaper should be gradually increased. During this process, when using the same sandpaper for polishing, keep polishing in the same direction until there are no other marks. Then rotate the sample 90° and use the sandpaper of the next mesh number for polishing.

[0035] (2) Using Hill Metal Cleaner and anhydrous ethanol as the cleaning solvent, the polished alloy and the cleaning solvent are placed in an ultrasonic cleaning apparatus for ultrasonic cleaning. The cleaning time is set to 5-10 minutes. The purpose of this cleaning is to remove various organic contaminants, such as oil stains, on the surface of the titanium aluminum alloy.

[0036] (3) The titanium aluminum alloy treated in (2) is placed in deionized water and ultrasonically cleaned for 5-10 minutes to further remove residual organic contaminants.

[0037] (4) The titanium aluminum alloy treated in (3) is placed in a drying oven for drying, with the drying temperature set at 70-80°C and the drying time set at 10-15 minutes.

[0038] (5) The titanium-aluminum alloy with a smooth and clean surface obtained after pretreatment is placed on a stage. The displacement of the stage is controlled by a three-dimensional high-precision mobile platform. The Z-axis displacement of the platform is adjusted so that the laser focus is focused on the alloy surface.

[0039] (6) Set the laser power to 10-20 mW, the repetition rate to 500 kHz, the scanning speed to 350-500 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the first laser processing according to the set parameters to achieve the first-level structure of the inverted triangle.

[0040] (7) Set the laser power to 20-30 mW, the repetition rate to 500 kHz, the scanning speed to 200-350 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the second laser processing according to the set parameters to achieve the second-level structure of the inverted triangle.

[0041] (8) Set the laser power to 30-40 mW, the repetition frequency to 500 kHz, the scanning speed to 50-200 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the third laser processing according to the set parameters to achieve the third-level structure of the inverted triangle.

[0042] (2) Template hot stamping:

[0043] (1) The titanium-aluminum alloy with a hierarchical inverted triangle microstructure formed on the surface was ultrasonically cleaned with anhydrous ethanol and deionized water for 5-10 minutes to remove impurities generated by laser processing, and then dried in a drying oven at 60°C for 10-20 minutes to remove weakly deposited particles generated by laser processing on the template surface.

[0044] (2) Soak the titanium-aluminum alloy template in a saturated stearic acid ethanol solution for 3-5 minutes to allow the stearic acid to fully enter the structure, thereby making it easier for the silicone rubber material to be demolded from the template during subsequent printing.

[0045] (3) Place the template on the heated lower platen of a compressor at a temperature of 120-150°C. When the template temperature reaches the same temperature, place the silicone rubber material on the template and compress it with the heated upper platen. Set the pressure to 0-25 MPa and maintain it for 3-5 minutes.

[0046] (4) After the hot stamping process is completed, the pressure is unloaded, and after the temperature of the compressor cools down to room temperature, the titanium aluminum alloy template and the silicone rubber material with a graded inverted triangle structure on the surface are taken out.

[0047] Example 1

[0048] (1) Use sandpaper of different specifications in the range of 200-1000 mesh to mechanically polish the surface of the titanium aluminum alloy. The mesh number of the sandpaper should be gradually increased. During this process, when using the same sandpaper for polishing, keep polishing in the same direction until there are no other marks. Then rotate the sample 90° and use the sandpaper of the next mesh number for polishing.

[0049] (2) Using Hill Metal Cleaner and anhydrous ethanol as the cleaning solvent, the polished alloy and the cleaning solvent were placed in an ultrasonic cleaning apparatus for 10 minutes. The purpose of this cleaning was to remove various organic contaminants, such as oil, from the surface of the titanium-aluminum alloy.

[0050] (3) The titanium aluminum alloy treated in (2) was placed in deionized water and ultrasonically cleaned for 10 minutes to further remove residual organic contaminants.

[0051] (4) The titanium-aluminum alloy treated in (3) is placed in a drying oven for drying, with the drying temperature set at 75°C and the drying time set at 15 minutes.

[0052] (5) The titanium-aluminum alloy with a smooth and clean surface obtained after pretreatment is placed on a stage. The displacement of the stage is controlled by a three-dimensional high-precision mobile platform. The Z-axis displacement of the platform is adjusted so that the laser focus is focused on the alloy surface.

[0053] (6) Set the laser power to 10 mW, the repetition rate to 500 kHz, the scanning speed to 350 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the first laser processing according to the set parameters to achieve the first-level structure of the inverted triangle.

[0054] (7) Set the laser power to 20 mW, the repetition rate to 500 kHz, the scanning speed to 200 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the second laser processing according to the set parameters to achieve the second-level structure of the inverted triangle.

[0055] (8) Set the laser power to 30 mW, the repetition frequency to 500 kHz, the scanning speed to 50 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the third laser processing according to the set parameters to achieve the third-level structure of the inverted triangle.

[0056] (9) The titanium-aluminum alloy with a hierarchical inverted triangle microstructure formed on the surface was ultrasonically cleaned with anhydrous ethanol and deionized water for 10 minutes to remove impurities generated by laser processing, and then dried in a drying oven at 60°C for 20 minutes to remove weakly deposited particles generated by laser processing on the template surface.

[0057] (10) The titanium-aluminum alloy template was immersed in a saturated stearic acid ethanol solution for 5 min to allow the stearic acid to fully enter the structure, thereby making it easier for the silicone rubber material to be demolded from the template during subsequent printing.

[0058] (11) Place the template on the heated lower platen of a compressor at 150°C. When the template temperature reaches the same temperature, place the silicone rubber material on the template and compress it with the heated upper platen. Set the pressure to 0-25 MPa and maintain it for 5 minutes.

[0059] (12) After the hot stamping process is completed, the pressure is unloaded, and after the temperature of the compressor cools down to room temperature, the titanium aluminum alloy template and the silicone rubber material with a graded inverted triangle structure on the surface are taken out.

[0060] Performance test: The water contact angle of the silicone rubber material with a graded inverted triangle structure on the surface prepared in this embodiment is 154.1°.

[0061] Example 2

[0062] (1) Use sandpaper of different specifications in the range of 200-1000 mesh to mechanically polish the surface of the titanium aluminum alloy. The mesh number of the sandpaper should be gradually increased. During this process, when using the same sandpaper for polishing, keep polishing in the same direction until there are no other marks. Then rotate the sample 90° and use the sandpaper of the next mesh number for polishing.

[0063] (2) Using Hill Metal Cleaner and anhydrous ethanol as the cleaning solvent, the polished alloy and the cleaning solvent were placed in an ultrasonic cleaning apparatus for 10 minutes. The purpose of this cleaning was to remove various organic contaminants, such as oil, from the surface of the titanium-aluminum alloy.

[0064] (3) The titanium aluminum alloy treated in (2) was placed in deionized water and ultrasonically cleaned for 10 minutes to further remove residual organic contaminants.

[0065] (4) The titanium aluminum alloy treated in (3) is placed in a drying oven for drying, with the drying temperature set at 80°C and the drying time set at 15 minutes.

[0066] (5) The titanium-aluminum alloy with a smooth and clean surface obtained after pretreatment is placed on a stage. The displacement of the stage is controlled by a three-dimensional high-precision mobile platform. The Z-axis displacement of the platform is adjusted so that the laser focus is focused on the alloy surface.

[0067] (6) Set the laser power to 15 mW, the repetition rate to 500 kHz, the scanning speed to 425 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the first laser processing according to the set parameters to achieve the first-level structure of the inverted triangle.

[0068] (7) Set the laser power to 25 mW, the repetition rate to 500 kHz, the scanning speed to 275 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the second laser processing according to the set parameters to achieve the second-level structure of the inverted triangle.

[0069] (8) Set the laser power to 35 mW, the repetition frequency to 500 kHz, the scanning speed to 125 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the third laser processing according to the set parameters to achieve the third-level structure of the inverted triangle.

[0070] (9) The titanium-aluminum alloy with a hierarchical inverted triangle microstructure formed on the surface was ultrasonically cleaned with anhydrous ethanol and deionized water for 10 minutes to remove impurities generated by laser processing, and then dried in a drying oven at 60°C for 20 minutes to remove weakly deposited particles generated by laser processing on the template surface.

[0071] (10) The titanium-aluminum alloy template was immersed in a saturated stearic acid ethanol solution for 5 min to allow the stearic acid to fully enter the structure, thereby making it easier for the silicone rubber material to be demolded from the template during subsequent printing.

[0072] (11) Place the template on the heated lower platen of a compressor at 150°C. When the template temperature reaches the same temperature, place the silicone rubber material on the template and compress it with the heated upper platen. Set the pressure to 0-25 MPa and maintain it for 5 minutes.

[0073] (12) After the hot stamping process is completed, the pressure is unloaded, and after the temperature of the compressor cools down to room temperature, the titanium aluminum alloy template and the silicone rubber material with a graded inverted triangle structure on the surface are taken out.

[0074] Performance test: The water contact angle of the silicone rubber material with a graded inverted triangle structure on the surface prepared in this embodiment is 156.3°.

[0075] Example 3

[0076] (1) Use sandpaper of different specifications in the range of 200-1000 mesh to mechanically polish the surface of the titanium aluminum alloy. The mesh number of the sandpaper should be gradually increased. During this process, when using the same sandpaper for polishing, keep polishing in the same direction until there are no other marks. Then rotate the sample 90° and use the sandpaper of the next mesh number for polishing.

[0077] (2) Using Hill Metal Cleaner and anhydrous ethanol as the cleaning solvent, the polished alloy and the cleaning solvent were placed in an ultrasonic cleaning apparatus for 10 minutes. The purpose of this cleaning was to remove various organic contaminants, such as oil, from the surface of the titanium-aluminum alloy.

[0078] (3) The titanium aluminum alloy treated in (2) was placed in deionized water and ultrasonically cleaned for 10 minutes to further remove residual organic contaminants.

[0079] (4) The titanium aluminum alloy treated in (3) is placed in a drying oven for drying, with the drying temperature set at 80°C and the drying time set at 15 minutes.

[0080] (5) The titanium-aluminum alloy with a smooth and clean surface obtained after pretreatment is placed on a stage. The displacement of the stage is controlled by a three-dimensional high-precision mobile platform. The Z-axis displacement of the platform is adjusted so that the laser focus is focused on the alloy surface.

[0081] (6) Set the laser power to 20 mW, the repetition rate to 500 kHz, the scanning speed to 500 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the first laser processing according to the set parameters to achieve the first-level structure of the inverted triangle.

[0082] (7) Set the laser power to 30 mW, the repetition rate to 500 kHz, the scanning speed to 350 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the second laser processing according to the set parameters to achieve the second-level structure of the inverted triangle.

[0083] (8) Set the laser power to 40 mW, the repetition frequency to 500 kHz, the scanning speed to 200 mm / s, the scanning spacing to 50 μm, and the number of repetitions to 2. Complete the third laser processing according to the set parameters to achieve the third-level structure of the inverted triangle.

[0084] (9) The titanium-aluminum alloy with a hierarchical inverted triangle microstructure formed on the surface was ultrasonically cleaned with anhydrous ethanol and deionized water for 10 minutes to remove impurities generated by laser processing, and then dried in a drying oven at 60°C for 20 minutes to remove weakly deposited particles generated by laser processing on the template surface.

[0085] (10) The titanium-aluminum alloy template was immersed in a saturated stearic acid ethanol solution for 5 min to allow the stearic acid to fully enter the structure, thereby making it easier for the silicone rubber material to be demolded from the template during subsequent printing.

[0086] (11) Place the template on the heated lower platen of a compressor at 150°C. When the template temperature reaches the same temperature, place the silicone rubber material on the template and compress it with the heated upper platen. Set the pressure to 0-25 MPa and maintain it for 5 minutes.

[0087] (12) After the hot stamping process is completed, the pressure is unloaded, and after the temperature of the compressor cools down to room temperature, the titanium aluminum alloy template and the silicone rubber material with a graded inverted triangle structure on the surface are taken out.

[0088] Performance test: The water contact angle of the silicone rubber material with a graded inverted triangle structure on the surface prepared in this embodiment is 153.8°.

[0089] The above-described embodiments merely represent specific implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A method for preparing a hierarchical inverted triangle microstructure on the surface of silicone rubber, characterized in that: The method comprises the following steps: Step S1, preparing a titanium-aluminum alloy template based on laser processing: etching the titanium-aluminum alloy surface by femtosecond laser, adjusting the laser processing spot diameter, pulse width, energy density, scanning speed and scanning spacing, and constructing a hierarchical inverted triangle microstructure on the titanium-aluminum alloy surface; Step S2, template hot stamping: After pre-treating the template, the silicone rubber material is placed on the template, compressed by a heated upper pressing plate, and appropriate stamping temperature, pressure and time are set. After cooling, the silicone rubber with an inverted triangular microstructure on the surface is obtained.

2. The method for preparing a hierarchical inverted triangle microstructure on the surface of silicone rubber according to claim 1, characterized in that: The hierarchical inverted triangle microstructure is formed by stacking three different levels of convex column arrays in sequence in the surface normal direction. The surface contour can be expressed by the following periodic function: Wherein, x is the horizontal direction of the front view of the titanium-aluminum alloy, y is the vertical direction of the front view of the titanium-aluminum alloy; the period of the function is T=50, and the unit is μm.

3. The method for preparing a hierarchical inverted triangle microstructure on the surface of silicone rubber according to claim 2, characterized in that: The hierarchical inverted triangle microstructure is processed on the surface of the titanium aluminum alloy by femtosecond laser etching. The laser etching scanning process includes: a first laser scan, setting the laser power to 10-20mW, the repetition frequency to 500KHz, the scanning speed to 350-500mm / s, the scanning spacing to 50μm, and the number of repetitions to 2 times, to achieve the first-level structure of the inverted triangle microstructure; a second laser scan, setting the laser power to 20-30mW, the repetition frequency to 500KHz, the scanning speed to 200-350mm / s, the scanning spacing to 50μm, and the number of repetitions to 2 times, to achieve the second-level structure of the inverted triangle microstructure; a third laser scan, setting the laser power to 30-40mW, the repetition frequency to 500KHz, the scanning speed to 50-200mm / s, the scanning spacing to 50μm, and the number of repetitions to 2 times, to achieve the third-level structure of the inverted triangle microstructure.

4. The method for preparing a hierarchical inverted triangle microstructure on a silicone rubber surface according to claim 1, characterized in that: The size of the titanium-aluminum alloy is 30mm×30mm×1.5mm, and its composition and proportions of each component are: titanium (Ti) 46wt%, aluminum (Al) 47wt%, vanadium (V) 2.5wt%, chromium (Cr) 1.5wt%, and niobium (Nb) 3wt%.

5. The method for preparing a hierarchical inverted triangle microstructure on a silicone rubber surface according to claim 1, characterized in that: The pretreatment comprises: ultrasonically cleaning the titanium-aluminum alloy template with a hierarchical inverted triangle microstructure formed on the surface with anhydrous ethanol and deionized water for 5-10 minutes in sequence to remove impurities generated by laser processing, and drying the template in a drying oven at 60° C. for 10-20 minutes.

6. The method for preparing a hierarchical inverted triangle microstructure on the surface of silicone rubber according to claim 5, characterized in that: The pretreatment further comprises: soaking the titanium-aluminum alloy template in a saturated stearic acid ethanol solution for 3-5 minutes to allow the stearic acid to fully penetrate the structure.

7. The method for preparing a hierarchical inverted triangle microstructure on a silicone rubber surface according to claim 1, characterized in that: The stamping temperature is 120-150°C, the pressure is 0-25 MPa, and is maintained for 3-5 minutes.

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