Water-gas separation device based on PDMS (Polydimethylsiloxane) super-hydrophobic membrane and preparation method and device of PDMS super-hydrophobic membrane

Abstract

The invention discloses a water-gas separation device based on a PDMS (Polydimethylsiloxane) super-hydrophobic membrane and a preparation method and device of the PDMS super-hydrophobic membrane, and relates to the technical field of functional surface processing and marine gas resource collection. The separation device comprises a dynamic flow field generation unit and a static interface selection unit, and the dynamic flow field generation unit generates an ascending flow field through a spiral blade to promote bubbles to float upwards quickly; the static interface selection unit adopts an inverted V-shaped PDMS film with a super-hydrophobic lower surface and a super-hydrophilic upper surface, so that efficient gas-liquid separation is realized; the device is provided with a self-adaptive floating system, and the PDMS film is always kept at the optimal working position through a floating plate and an adjusting mechanism. According to the invention, the double-sided super-hydrophobic / super-hydrophilic porous PDMS film is obtained through a template reetching method. The methane bubble collecting device effectively solves the problems of water pressure permeation and low efficiency in the bubble collecting process, has the advantages of being stable in structure, high in collecting efficiency and the like, is particularly suitable for methane bubble collection in the marine environment, and can effectively reduce greenhouse gas emission and achieve energy recycling.

Description

Technical Field

[0001] The present invention relates to the technical fields of micro-nanostructure surface engineering and gas-liquid interface regulation, and in particular to a water-gas separation device based on a PDMS super-hydrophobic membrane and a method and device for preparing the PDMS super-hydrophobic membrane. Background Art

[0002] In nature, most methane (CH4) exists as solid gas hydrates on the seafloor. Directly releasing methane into the atmosphere would exacerbate the greenhouse effect and lead to changes in terrestrial and aquatic ecosystems, significantly impacting global ecosystems, economies, and societies. At the same time, the large amount of methane bubbles emanating from the seabed can be considered a valuable energy source, as methane combustion produces only small amounts of carbon dioxide and no pollutants such as sulfides and particulate matter. Unfortunately, collecting methane bubbles from the seabed for further utilization also faces challenges such as slow bubble ascent and easy dispersion. Bubble ascent in static water is constrained by factors such as buoyancy and viscous drag, and the collection path is unstable. Furthermore, conventional collection methods often overlook the effects of incomplete water-gas separation and the influence of material surface properties on bubble behavior. Therefore, uncovering the mechanisms of efficient bubble adsorption and directional transport, and developing long-term stable bubble collection devices based on these mechanisms, would be of great value to theoretical innovation and engineering practice in deep-sea resource development and greenhouse gas emission reduction.

[0003] Domestic and international scholars have conducted extensive research on the fabrication of underwater bubble collection devices. Patent application number CN202320613341.0 utilizes a first pump to regulate water flow velocity, simulating different hydraulic conditions impacting sediments to release methane bubbles. The Venturi effect and airflow deflection in the bend effectively separate methane from water, ultimately collecting the gas in a gas collection bottle. Patent application number CN201621153648.3 utilizes a molecular sieve trap to dry out bubbles in geothermal water, which are then transferred to a sampler via a syringe. A high-precision diaphragm flowmeter is then used to perform pressure testing to ensure the collected gas pressure is above 1 atmosphere, preventing air pollution. This method overcomes the high humidity of the collected gas, the difficulty in accurately measuring its volume, and the potential for environmental pollution caused by the low pressure, common with conventional exhaust methods. However, the molecular sieve trap requires frequent replacement, increasing operational complexity and cost. Furthermore, the sealability of the injector can affect gas collection accuracy.

[0004] The main defects and disadvantages of current technology are: the complex structure of the device leads to high manufacturing and maintenance costs; the risk of gas cross-contamination is significant, and the water-gas separation is incomplete, which easily leads to a decline in the quality of methane gas collection; at the same time, the device is difficult to adapt to changes in different hydraulic conditions, lacks flexibility in operating condition adjustment, and has low collection efficiency, which limits its promotion in actual application scenarios. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention provides a water-gas separation device based on a PDMS super-hydrophobic membrane, and a method and device for preparing the PDMS super-hydrophobic membrane. The method utilizes an underwater super-hydrophobic / hydrophilic unidirectional transmission porous membrane to intercept bubbles, thereby efficiently collecting and utilizing underwater methane bubbles. The present invention utilizes a laser-electrochemical deposition continuous processing method to prepare the PDMS membrane, prepares a micro-nano composite structure rich in nano-nickel pyramids on a copper surface, adjusts the laser scanning gap so that the contact angle of the super-hydrophobic surface reaches a maximum value, i.e., the super-hydrophobic state is most stable, and uses a template method to replicate one side of a PDMS membrane with the same properties. A uniform conical micropore array is processed on the other side of the PDMS film, and the surface is modified with a super-hydrophilic reagent, thereby obtaining a PDMS membrane with a super-hydrophilic upper surface and a super-hydrophobic lower surface.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] The water-gas separation device based on the PDMS super-hydrophobic membrane includes a container, a PDMS membrane and a floating plate; the container is a hollow cavity, placed in seawater, and suspended by the floating plate; the upper end of the container is connected to an air pipe, and the lower end of the container is provided with a PDMS membrane; the upper surface of the PDMS membrane has super-hydrophilic properties and the lower surface has super-hydrophobic properties; the gas that passes through the PDMS membrane is collected into the gas storage container through the air pipe.

[0008] In the above solution, the container is an inverted V-shaped structure with an inclination angle of 10° to 20°; the PDMS membrane is arranged in an inverted V-shaped structure with an inclination angle of 3° to 5°.

[0009] In the above solution, the floating plate is sleeved on the outer ring of the container through a support frame. The floating plate is a hollow honeycomb structure, and the transverse dimension L of the floating plate is 0.6 to 1.2 m.

[0010] In the above solution, a negative pressure exhaust device is provided in the gas pipeline.

[0011] In the above solution, the container is further provided with a rigid link mechanism, and the rigid link mechanism is connected with a spiral blade, which is placed below the PDMS membrane and is used to stir the seawater so that bubbles quickly reach the PDMS membrane.

[0012] A method for preparing a PDMS super-hydrophobic / hydrophilic double-sided porous membrane induced by template-assisted laser-electrochemical deposition comprises the following steps:

[0013] Step 1) preparing a super-hydrophobic copper surface micro-nano composite structure;

[0014] Step 2) preparing a super-hydrophobic micro-nano structure surface on one side of the PDMS film using a replica method according to the super-hydrophobic copper surface micro-nano composite structure obtained in step 1;

[0015] Step 3) Use nanolaser to process a uniform conical micropore array on the PDMS film, and modify the surface of the PDMS film where the uniform conical micropore array is processed with a superhydrophilic reagent to obtain superhydrophilic properties, thereby obtaining a superhydrophilic surface, and finally obtaining a PDMS membrane with a superhydrophilic upper surface and a superhydrophobic lower surface.

[0016] In the above scheme, step one includes mechanical polishing, laser ablation, electrochemical polishing and electrochemical deposition.

[0017] In the above scheme, the wavelength of the laser is 1000~1200nm, the pulse width is 10~15ps, the repetition frequency is 1MHz, the output power is 10~25W, the scanning speed is set at 150~300mm / s, the number of scans is 25~30 times, the focused spot diameter is 20~30μm, and the laser scanning gap is equal to the focused spot diameter.

[0018] In the above scheme, in step three, the gap between two adjacent holes is set to 300-500 μm, the micropore diameter is 100-150 μm, and the conical micropore array covers the entire effective area of the film in a hexagonal close-packed configuration (HCP).

[0019] The invention discloses an apparatus for realizing a method of inducing a PDMS super-hydrophobic / hydrophilic double-sided porous membrane by template-assisted laser-electrochemical deposition, characterized in that it comprises a picosecond pulse laser system for ablating microstructures, an electrochemical polishing system for growing nanostructures, and an electrochemical deposition system; the picosecond pulse laser system is used to ablate a workpiece; in the electrochemical polishing system, the workpiece is connected to the positive electrode of a power supply, a lead plate is connected to the negative electrode of a power supply, and the workpiece is placed in a polishing liquid; in the electrochemical deposition system, the workpiece is placed in an electrolyte, the workpiece is connected to the negative electrode of a power supply, and a nickel block is connected to the positive electrode of a power supply; and a micro-nano composite structure is obtained through electrochemical polishing and electrochemical deposition.

[0020] Beneficial effects:

[0021] 1. The rotation of the spiral blades in the present invention can form a dynamic flow field, accelerate the upwelling of bubbles, break the limitations of bubble collection in traditional static water conditions, avoid the accumulation and retention of bubbles in specific areas, and significantly improve the efficiency of bubble capture.

[0022] 2. In the present invention, the top of the container is designed to be inverted V-shaped with rounded corners to reduce gas accumulation and retention caused by the formation of vortices and turbulence, making it easier for gas to float and gather on the inclined surface. The negative pressure exhaust device is connected to the top of the container through an air pipe. The exhaust device accelerates the extraction of collected methane gas, further improving the collection efficiency and utilization rate of methane gas, thereby effectively alleviating environmental pollution and energy problems.

[0023] 3. The present invention constructs a bubble collection device that integrates a dynamic flow field generation module (spiral blades), a static interface selection module (double-sided super-hydrophobic / super-hydrophilic PDMS membrane) and a drag-reducing container configuration, and realizes efficient enrichment and continuous separation of bubbles through the collaborative coupling of multiple physical fields.

[0024] 4. Conventional devices that utilize superhydrophobic properties to collect bubbles often assume that the lower surface of the membrane is also superhydrophobic and that water-vapor separation can be achieved directly after the membrane is perforated. In practice, water can seep in through the perforations, affecting bubble collection efficiency. The floating plate in this invention utilizes a hollow honeycomb structure to achieve a precise buoyancy-gravity balance, maintaining the lower surface of the membrane at the water boundary and preventing hydrostatic pressure from damaging the PDMS membrane. The lateral dimensions of the floating plate (L = 1.2 m) are much larger than the wave wavelength (typical ocean waves have a wavelength of λ ≈ 0.5 m). The principle of frequency detuning is used to suppress the resonant response, reducing the heave amplitude of the membrane surface by approximately 70%. Furthermore, the lower surface is superhydrophobic, while the upper surface of the PDMS membrane is superhydrophilic and has a sloped design. Through the synergistic effect of the surface superhydrophobicity and gravity-driven drainage, when some bubbles rise to the PDMS membrane with the water flow, the water spreads out on the superhydrophilic surface and slides down the slope, effectively solving the problem of water seepage through the membrane pores and achieving dual protection for water-vapor separation.

[0025] 5. In the present PDMS membrane preparation method, the copper-based template, prepared using laser-electrochemical deposition, exhibits excellent mechanical durability and can achieve over 30 repetitive PDMS membrane transfers, significantly improving preparation efficiency and reducing production costs. The present invention utilizes a template etching method to prepare the PDMS film. This method offers a simple preparation process, eliminates the need for complex processing equipment, and allows for multiple reuse of the template, saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of a water-gas separation device based on a PDMS super-hydrophobic membrane according to the present invention;

[0027] Figure 2 Schematic diagram of the experimental device for preparing super-hydrophobic copper surface micro-nano composite structure according to the present invention;

[0028] Figure 3 Schematic diagram of the overall continuous preparation process flow of cross-scale micro-nano composite structures and 3D concave corner structures on super-hydrophobic copper surfaces.

[0029] Reference numerals:

[0030] 1-negative pressure exhaust device; 2-gas pipe; 3-container; 4-PDMS membrane; 5-rigid linkage mechanism; 6-bubble; 7-spiral blade; 8-seawater; 9-floating plate; 10-support frame; 11-workpiece; 12-pulse power supply; 13-lead plate; 14-polishing liquid; 15-electrolyte; 16-nickel block; 17-focusing lens; 18-reflector; 19-aperture; 20-nanosecond laser; 21-power supply. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below. The embodiments described below with reference to the accompanying drawings are merely exemplary contents, intended to explain the present invention, and should not be construed as limiting the present invention.

[0032] Combined with attachment Figure 1 As shown, a water-gas separation device based on a PDMS super-hydrophobic membrane includes a container 3, a PDMS membrane 4 and a floating plate 9; the container 3 is a hollow cavity, the container 3 is placed in seawater 8, and the container 3 is suspended by the floating plate 9, the upper end of the container 3 is connected to the gas pipe 2, and the lower end of the container 3 is provided with a PDMS membrane 4, the upper surface of the PDMS membrane 4 is super-hydrophilic, and the lower surface is super-hydrophobic; the gas passing through the PDMS membrane 4 is collected into the gas storage container through the gas pipe 2.

[0033] A transparent and durable material is selected to make the uncovered container 3, which is convenient for observing the movement of the bubbles 6. The bottom of the container is designed to be a V-shaped structure with a V-shaped angle of about 160°, that is, the angle of the inclined surface is 10° to 20°. The folded parts are rounded to reduce the formation of eddies and turbulence, making it easier for the gas to float and gather on the inclined surface. The container is placed upside down underwater.

[0034] The prepared double-sided super-hydrophobic / super-hydrophilic PDMS membrane 4 is cut into a suitable size and shape and is beveled. It is folded in the middle to form a V-shaped structure with a V-shaped angle of about 170°, that is, the bevel angle is 3°~5°. The folded part is rounded to facilitate water spreading and sliding on the super-hydrophilic surface. The designed PDMS membrane 4 is installed on the uncovered side of the container to ensure that the membrane fits tightly to the container.

[0035] An annular floating plate 9 with a hollow honeycomb structure is provided on the outer side of the upper portion of the container 3 and is connected to the container via a support frame 10. The floating plate has a transverse dimension L = 1.2 m and is made of a low-density composite material with a density of 0.3-0.5 g / cm 3The support frame has an adjustment accuracy of ≤±1mm and its inner diameter is 10-15cm larger than the outer diameter of the container, providing additional buoyancy without affecting bubble observation. Through the dynamic buoyancy compensation of the floating plate, it can automatically adapt to different water depths and wave conditions to maintain stable operation of the system.

[0036] The top of the container is connected to the negative pressure exhaust device 1 through the air supply pipe 2, which is used to ensure that the gas can accelerate the output of the gas. The negative pressure exhaust device is located above the water surface.

[0037] The lower part of the container is connected to the spiral blade 7 through a rigid connecting rod mechanism 5, which is used to break the static water state and form a dynamic flow field, which can reduce the relative speed between the bubbles and the water, thereby reducing the resistance of the water and the influence of the surface tension.

[0038] Experimental operation and bubble collection:

[0039] The spiral blades 7 rotate, causing the seawater 8 to form an upward flow field; water containing methane bubbles is poured into a container, and the upwelling of bubbles and the separation of water and gas are observed; when the methane gas accumulates to a certain amount on the inclined surface, the negative pressure exhaust device is turned on to extract the gas and collect it in a designated gas storage container; the collected methane gas is tested for purity and flow rate to ensure that it meets application requirements.

[0040] A method for separating water and gas by using a template-assisted laser-electrochemical deposition-induced PDMS super-hydrophobic film, comprising the following steps:

[0041] 1) Overall continuous preparation of cross-scale micro-nano composite structures and 3D concave corner structures on super-hydrophobic copper surfaces:

[0042] Combined with attachment Figure 3 In the illustrated embodiment, the continuous preparation process includes mechanical polishing, laser ablation, electrochemical polishing, and electrochemical deposition;

[0043] Mechanically polish the copper surface to a mirror finish:

[0044] In this embodiment, the Figure 2As shown in the figure, during the laser ablation process, an ultrashort pulse laser in the near-infrared band is used to periodically scan the copper substrate. The laser scanning gap is approximately equal to the focused spot diameter to achieve the maximum contact angle. By precisely controlling the laser energy density, scanning rate and scanning strategy, a regular micron-scale groove array structure is formed on the copper surface. Specifically, during the laser ablation process, the laser wavelength is 1000-1200nm, and the pulse width is 10-15ps, showing a relatively short pulse duration. The repetition frequency is set to 1MHz to ensure high-frequency laser action. The output power is 10-25W. The scanning speed is set to 150-300mm / s to achieve fast and uniform scanning. The number of scans is 25-30 times to ensure sufficient laser action times. The focused spot diameter is approximately 20-30μm. The laser scanning gap is adjusted so that the laser scanning gap is equal to the focused spot diameter. At this time, the contact angle of the superhydrophobic surface at room temperature reaches the maximum value, and the rolling angle reaches the minimum value. The nanostructure enables the composite structure to capture more air, allowing water droplets to contact the sample surface through the air. The abundant submicron-nanopyramids enhance the ability to capture air and reduce the contact area between the water droplet and the substrate to obtain a stable Cassie state.

[0045] During the electrochemical polishing process, a copper sample (workpiece 11) serves as the anode, a 99.99% pure lead plate (13) serves as the cathode, and a polishing solution (14) contains an alkaline electrolyte and a surfactant. The copper sample is then activated by soaking in an acidic solution for 20 seconds, then rinsed with deionized water and then transferred to the electrochemical deposition step.

[0046] During deposition, the copper sample is turned into cathode, the high purity nickel block 16 is used as anode, and the electrolyte 15 contains Ni 2+ Ion source, pH buffer and crystal modifier are added to adjust the pH of the electrolyte to the weak acid range and carried out at a constant temperature of about 65°C.

[0047] The deposition process is divided into two stages: using a stepped current control method, by adjusting the current density parameters in stages, first forming a primary nanocone array on the surface of the laser-ablated micron structure, and then constructing a secondary nanopyramid on the surface of the primary structure, and finally obtaining a composite structure with three-level hierarchical characteristics of micron-submicron-nano.

[0048] 2) Template method to replicate superhydrophobic PDMS surface

[0049] After the polydimethylsiloxane prepolymer and curing agent are mixed in a specific mass ratio and fully homogenized, they are transferred to a vacuum degassing device to complete gradient degassing treatment. After a precise temperature-controlled curing process, a polydimethylsiloxane (PDMS) film with high mechanical stability and controllable rheological properties is formed;

[0050] The superhydrophobic copper surface obtained in 1) is used as a template and shaped into a container using a mold. A thin layer of release agent is coated on the surface. The prepared liquid PDMS is cast on the copper surface for replication. It is left naturally for 24 hours to solidify. The template is peeled off to obtain a transparent PDMS film with a micro-nano hierarchical composite structure.

[0051] 3) Preparation of super hydrophobic / hydrophilic double-sided porous PDMS membrane:

[0052] During the processing process, a nanosecond laser is used to create a uniform array of conical micropores in the PDMS membrane. In this example, the gap between adjacent pores is set to approximately 500 μm, covering the entire active area of the membrane. The micropores have a diameter of 100 μm. A high-surface-energy superhydrophilic reagent is then applied to the other side of the PDMS membrane. After evaporation, this surface becomes superhydrophilic, resulting in a porous PDMS membrane with one side being superhydrophobic and the other superhydrophilic.

[0053] The gap between two adjacent pores is set to about 300-500 μm, the micropore diameter is 100-150 μm, and the tapered micropore array covers the entire effective area of the film in a hexagonal close-packed configuration (HCP).

[0054] Combined with attachment Figure 2 As shown, a device for preparing a super-hydrophobic copper surface micro-nano composite structure includes a picosecond pulse laser system for preparing a micron structure and an electrochemical polishing and electrochemical deposition system for preparing a nanostructure; the picosecond pulse laser system is used to ablate a workpiece 11, in the electrochemical polishing system, the workpiece 11 is connected to the positive pole of a power supply 12, the lead plate 13 is connected to the negative pole of the power supply 12, and the workpiece 11 is placed in a polishing liquid 14, in the electrochemical deposition system, the workpiece 11 is placed in an electrolyte 15, the workpiece 11 is connected to the negative pole of the power supply 12, and the nickel block 16 is connected to the positive pole of the power supply 12, and the micro-nano composite structure is obtained through electrochemical polishing and electrochemical deposition.

[0055] Compared to hydrophobic surfaces produced by laser ablation alone, the micro-raised surfaces fabricated by laser-electrochemical deposition are covered with dense nano-nickel pyramids, forming a cross-scale micro-nano composite structure and a 3D concave angle structure, significantly improving hydrophobicity. By varying the scanning gap during laser ablation, the micro-nano composite structure on the copper sample surface was modified. When the laser scanning gap equaled the spot diameter, the sample exhibited the most optimal and stable superhydrophobic properties, with a contact angle of up to 161° and a rolling angle as low as 1°.

[0056] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0057] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A water-gas separation device based on a PDMS super-hydrophobic membrane, characterized in that: The invention comprises a container (3), a PDMS membrane (4) and a floating plate (9); the container (3) is a hollow cavity, the container (3) is placed in seawater (8), and the container (3) is suspended by the floating plate (9); the upper end of the container (3) is connected to a gas transmission pipe (2), and the lower end of the container (3) is provided with a PDMS membrane (4); the upper surface of the PDMS membrane (4) is super-hydrophilic and the lower surface is super-hydrophobic; the gas passing through the PDMS membrane (4) is collected into a gas storage container through the gas transmission pipe (2).

2. the water-gas separation device based on PDMS super-hydrophobic membrane according to claim 1, is characterized in that, The container (3) is an inverted V-shaped structure with an inclined surface angle of 10° to 20°; the PDMS membrane (4) is arranged in an inverted V-shaped structure with an inclined surface angle of 3° to 5°.

3. The water-gas separation device based on the PDMS super-hydrophobic membrane according to claim 1, wherein The floating plate (9) is sleeved on the outer ring of the container (3) through a support frame (10); the floating plate (9) is a hollow honeycomb structure; and the transverse dimension L of the floating plate is 0.6 to 1.2 m.

4. The water-gas separation device based on the PDMS super-hydrophobic membrane according to claim 1, wherein A negative pressure air extraction device (1) is provided in the air delivery pipe (2).

5. The water-gas separation device based on the PDMS super-hydrophobic membrane according to claim 1, wherein The container (3) is further provided with a rigid link mechanism (5), the rigid link mechanism (5) being connected with a spiral blade (7), the spiral blade (7) being placed below the PDMS membrane (4), and the spiral blade (7) being used to stir the seawater (8) so that the bubbles (8) quickly reach the PDMS membrane (4).

6. A method for preparing a PDMS super-hydrophobic / hydrophilic double-sided porous membrane induced by template-assisted laser-electrochemical deposition, characterized in that: The following steps are involved: Step 1) preparing a super-hydrophobic copper surface micro-nano composite structure; Step 2) preparing a super-hydrophobic micro-nano structure surface on one side of the PDMS film using a replica method according to the super-hydrophobic copper surface micro-nano composite structure obtained in step 1; Step 3) Using a nano-laser to process a uniform conical micropore array on the PDMS film, and using a super-hydrophilic reagent to modify the surface of the PDMS film where the uniform conical micropore array is processed to obtain super-hydrophilic properties, thereby obtaining a super-hydrophilic surface, and finally obtaining a PDMS film with a super-hydrophilic upper surface and a super-hydrophobic lower surface (4).

7. The method for preparing a PDMS super-hydrophobic / hydrophilic double-sided porous membrane induced by template-assisted laser-electrochemical deposition according to claim 6, characterized in that: Step one includes mechanical polishing, laser ablation, electrochemical polishing and electrochemical deposition.

8. The method for preparing a PDMS super-hydrophobic / hydrophilic double-sided porous membrane induced by template-assisted laser-electrochemical deposition according to claim 7, characterized in that: The wavelength of the laser is 1000~1200nm, the pulse width is 10~15ps, the repetition frequency is 1MHz, the output power is 10~25W, the scanning speed is set at 150~300mm / s, the number of scans is 25~30 times, the focused spot diameter is 20~30μm, and the laser scanning gap is equal to the focused spot diameter.

9. The method for preparing a PDMS super-hydrophobic / hydrophilic double-sided porous membrane induced by template-assisted laser-electrochemical deposition according to claim 6, characterized in that: In step three, the gap between two adjacent pores is set to 300-500 μm, the micropore diameter is 100-150 μm, and the tapered micropore array covers the entire effective area of the film in a hexagonal close-packed configuration (HCP).

10. A device for implementing the method of template-assisted laser-electrochemical deposition-induced PDMS super-hydrophobic / hydrophilic double-sided porous membrane according to any one of claims 6 to 9, characterized in that: The invention comprises a picosecond pulse laser system for ablating micron structures, an electrochemical polishing system for growing nanostructures, and an electrochemical deposition system. The picosecond pulse laser system is used to ablate a workpiece (11). In the electrochemical polishing system, the workpiece (11) is connected to the positive electrode of a power supply (12), a lead plate (13) is connected to the negative electrode of the power supply (12), and the workpiece (11) is placed in a polishing liquid (14). In the electrochemical deposition system, the workpiece (11) is placed in an electrolyte (15), the workpiece (11) is connected to the negative electrode of the power supply (12), and a nickel block (16) is connected to the positive electrode of the power supply (12). A micro-nano composite structure is obtained through electrochemical polishing and electrochemical deposition.

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