A two-dimensional nanomesh material with leaf vein-like network structure and a preparation method thereof

Abstract

The application relates to a two-dimensional nanometer net material with a leaf vein network structure and a preparation method thereof. In the preparation process, polymer short fibers, a crosslinking agent and a surfactant are added into a polymer solution, and a net laying mixed solution is obtained through high-speed mechanical stirring; then the net laying mixed solution is uniformly coated on the surface of a fiber base material to form a polymer liquid film; then the polymer liquid film is subjected to phase separation into pores through a directional ultrasonic non-solvent bath immersion method, a nanometer fiber net is formed, the polymer short fibers are arranged in an orientation arrangement trend, and a leaf vein structure is constructed in the nanometer fiber net; then the nanometer fiber net is subjected to heat crosslinking treatment, and finally, the two-dimensional nanometer net with the leaf vein network structure is obtained. Compared with the prior art, the leaf vein network structure formed by the oriented arrangement of the polymer short fibers in the two-dimensional nanometer net material can reduce the pore diameter of the nanometer fiber net and provide mechanical support for the nanometer fiber net, so that the filtering performance and the mechanical performance of the material are enhanced, and the actual application requirements are met.

Description

Technical Field

[0001] This invention relates to the field of nanofiber materials technology, and in particular to a two-dimensional nanofiber mesh material with a leaf vein-like network structure and its preparation method. Background Technology

[0002] Nonwoven fiber materials possess advantages such as a wide range of raw material sources, simple processing methods, and strong structural adjustability, making them promising for applications in air filtration, oil-water separation, and waterproofing / breathability. The highly interconnected pore structure of nonwoven fiber materials is primarily composed of the disordered stacking of micron-sized fibers. Most nonwoven fiber materials, including spunlace, needle-punched, spunbond, and meltblown materials, have fiber diameters exceeding 5 μm. Electrospun fiber materials, through stretching and refining a polymer solution jet in a high-voltage electric field, can reduce the diameter to below 1 μm, but their mechanical properties are relatively poor, requiring combination with other materials in practical applications.

[0003] Patent CN201711084713.0 discloses a bacterial cellulose membrane composite material with a nano-spiderweb structure and its preparation method. The method involves dropping a culture solution onto a non-woven fabric and allowing it to grow statically, resulting in the growth of main bacterial cellulose and branched bacterial cellulose to form a bacterial cellulose membrane. While this method yields a nano-spiderweb bacterial cellulose membrane with a branched structure through bacterial growth, it suffers from problems such as a long bacterial growth cycle and uncontrollable growth process, leading to prolonged material preparation time and difficulty in precisely controlling the mesh branching structure.

[0004] Patent CN202210060014.7 discloses "A Preparation Method of Single-Layer Carbon Nanostructured Network Material and Its Application," which involves pretreating biomass raw materials, hydrothermally synthesizing biomass precursors, and then obtaining sheet-like carbon nanostructured networks through segmented calcination. The carbon nanostructured networks prepared by this method have small diameters, but the mechanical properties of the carbon nanostructured networks obtained after high-temperature calcination are poor, and they are prone to brittleness, limiting their practical application.

[0005] Patent CN202110226067.7 discloses a method for preparing a nano-arabbit fiber membrane. The method involves adding a template agent, polyvinylpyrrolidone, a solvent, ethanol, and isopropyl titanate as a titanium source, and acetic acid as a hydrolysis inhibitor, to obtain a spinning solution. Electrospinning is then performed to obtain a titanium oxide / polyvinylpyrrolidone nano-arabbit fiber membrane. The nano-arabbit membrane obtained by this method has a diameter of 10–50 nm. However, during electrospinning, the hydrolysis process is uncontrollable, the spinning solution is prone to gelation, and the requirements for the spinning environment are high. Furthermore, the organic template fibers are not removed by calcination, resulting in poor mechanical properties of the final fiber membrane. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems by providing a two-dimensional nanonet material with a leaf vein-like network structure and its preparation method, thereby obtaining a two-dimensional nanonet material with excellent mechanical properties and self-support.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] The first aspect of this invention provides a method for preparing a two-dimensional nanonet material with a leaf vein-like network structure, comprising the following steps:

[0009] S1: Add polymer short fibers, surfactants and crosslinking agents to the polymer solution, and then mechanically stir at high speed to obtain a web-laying mixture;

[0010] S2: The web-laying mixture is uniformly coated onto the surface of the porous fiber substrate using a uniformly scraping method with a scraping roller, thereby forming an ultra-thin continuous liquid film on the surface of the porous fiber substrate.

[0011] S3: The coated nanofiber substrate is immersed in a non-solvent bath of directional ultrasonic vibration. The directional ultrasonic vibration causes the polymer short fibers on the coated nanofiber substrate to be oriented and arranged. Among them, the polymer short fibers with larger diameters form a leaf vein-like structure. At the same time, the liquid film undergoes phase separation in the non-solvent to form a nanofiber network. After drying to remove the liquid phase, an uncrosslinked two-dimensional nanonet with a leaf vein-like network structure is obtained.

[0012] S4: The uncrosslinked two-dimensional nanonet with a leaf vein-like network structure is thermally crosslinked to allow the crosslinking agent monomer to undergo a crosslinking reaction between the nanofiber network and the polymer short fiber, thereby enhancing the bonding force between the nanofiber network and the polymer short fiber, and finally obtaining a two-dimensional nanonet with a leaf vein-like network structure.

[0013] Further, in S1, the polymer in the polymer solution is selected from one or more of cellulose, polyamide-imide, polyether-imide, polyvinylidene fluoride, polyacrylonitrile, polystyrene, polyamide, polyurethane, and polyvinyl alcohol, and the mass fraction of the polymer in the polymer solution is 0.1 to 10 wt%.

[0014] In S1, the solvent is selected from one or more of ethanol, isobutanol, n-propanol, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, ethyl acetate, acetone, and N-methylmorpholine-N-oxide;

[0015] In S1, the polymer short fiber is selected from one or more of polyethylene short fiber, polypropylene short fiber, polytetrafluoroethylene short fiber, polyimide short fiber, polyamide short fiber, and polyethylene terephthalate short fiber. The polymer short fiber has a diameter of 0.5-2 μm, a length of 0.5-3 mm, and a mass fraction of 0.1-5 wt% in the web-laying mixture.

[0016] Further, in S1, the surfactant is selected from one or more of the following: cocoyl monoethanolamide, cocoyl diethanolamide, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, dodecyltrimethylammonium bromide, potassium lauryl ether phosphate, disodium lauryl sulfosuccinate monoester, monolauryl phosphate, fatty alcohol polyoxyethylene ether ammonium sulfate, lauramidopropyl betaine, and the surfactant mass fraction is 0.01-5 wt%.

[0017] In S1, the crosslinking agent is selected from one or more of tetraethyl orthosilicate, methyl orthosilicate, trimethoxysilane, acrylate, isocyanate, propylenediamine, styrene, aziridine, N,N'-1,4-phenylene dimaleimide, N,N'-(4,4'-methylenediphenyl)bismaleimide, and 2,2'-bis[4-(4-maleimide-phenoxy)phenyl]propane, and the mass fraction of the crosslinking agent is 0.1-10 wt%.

[0018] In S1, the rotation speed of the high-speed mechanical stirring is 500 to 1500 rpm.

[0019] Furthermore, in S2, the scraper roller is made of stainless steel, has a circular cross-section with a diameter of 5–20 mm, a length of 10–50 cm, a pressure of 0.1–10 kg, a speed of 5–100 cm / min, and a film thickness of 0.5–100 μm.

[0020] Further, in S2, the porous fiber substrate is selected from one of electrospun fiber membrane, nonwoven fabric, cellulose filter paper, woven fabric, and knitted fabric. The fiber diameter of the porous fiber substrate is 0.6 to 3 μm, the pore size of the substrate is 1 to 5 μm, and the thickness of the substrate is 10 to 80 μm.

[0021] Furthermore, in S3, the non-solvent is selected from one or more of water, methanol, ethanol, propanol, isobutanol, ethylene glycol, acetone, cresol, and cyclohexane.

[0022] Furthermore, in S3, the direction of the directional ultrasound is parallel to the plane of the substrate, the ultrasonic power is 0.1 to 1 kW, and the ultrasonic frequency is 10 to 50 kHz.

[0023] Furthermore, in S3, the phase separation time is 10–120 min, and the phase separation temperature is 20–50 °C.

[0024] Furthermore, in S4, the thermal crosslinking heating method is a gradient heating, which goes through multiple heating-holding stages from the initial temperature to the final temperature. The initial temperature is 20-30℃, the final temperature is 100-160℃, the heating rate is 1-10℃ / min, and the holding time is 10-40min.

[0025] A second aspect of the present invention provides a two-dimensional nanomesh material with a leaf vein-like network structure prepared by the above method, wherein the fiber diameter of the two-dimensional nanomesh is bimodal, wherein the fiber diameter of the nanofiber mesh is 10-50 nm and the fiber diameter of the polymer short fiber is 0.5-2 μm; the pore size of the two-dimensional nanomesh is 200-800 nm and the tensile strength is 5-20 MPa.

[0026] The technical principle of this invention is as follows:

[0027] The two-dimensional nanonet with a leaf vein-like network structure in this invention is obtained by coating a polymer solution doped with short polymer fibers, surfactants, and crosslinking agents onto the surface of a porous fiber substrate, then immersing it in a directional ultrasonic non-solvent bath for phase separation and thermal crosslinking treatment.

[0028] First, this invention further dissociates and disperses the short polymer fibers in the mixed web-laying solution through high-speed mechanical stirring, and fully dissolves the surfactant and crosslinking agent in the solvent to obtain the web-laying solution. After uniformly coating the web-laying solution onto the surface of a porous fiber substrate, the material is immersed in a non-solvent bath subjected to directional ultrasonic vibration. The ultrasonic vibration accelerates the double diffusion between solvent and non-solvent molecules, speeding up the aggregation and nucleation growth rate of the solvent-rich phase, thereby promoting the process of phase separation to form a two-dimensional mesh structure. At the same time, the direction of directional ultrasonic vibration is parallel to the substrate plane, promoting the oriented alignment of the short polymer fibers in the liquid film, forming a leaf-vein-like structure. During the thermal crosslinking treatment of the two-dimensional nanomesh, the active functional groups on the crosslinking agent monomer react with the macromolecules of the nanofiber mesh and the polymer short fiber macromolecules to form a crosslinked network, enhancing the bonding force between the nanofiber mesh and the polymer short fibers. The larger diameter polymer short fibers provide mechanical support for the smaller diameter nanofiber mesh, thereby improving the structural stability of the material and enhancing its mechanical properties.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) Compared with existing nanonet materials, the present invention constructs a leaf vein-like structure in a two-dimensional nanonet structure, which improves the structural stability of the two-dimensional nanonet and enhances the mechanical properties of the material.

[0031] (2) The two-dimensional nano-network structure with leaf vein-like network structure described in this invention has strong tunability, and the dual-component composition enriches its functionality, meeting the functional requirements in various application scenarios. Detailed Implementation

[0032] This invention discloses a method for preparing a two-dimensional nanonet with a leaf-vein-like network structure. The method specifically involves: first, adding polymer short fibers, a crosslinking agent, and a surfactant to a polymer solution and then mechanically stirring at high speed to obtain a web-laying mixture; subsequently, uniformly coating the web-laying mixture onto the surface of a fiber substrate to form a polymer liquid film; then, using a directional ultrasonic non-solvent bath impregnation method to induce phase separation and pore formation in the polymer liquid film, forming a nanofiber web, while simultaneously aligning the polymer short fibers to construct a leaf-vein-like structure within the nanofiber web; finally, subjecting it to thermal crosslinking treatment to obtain the final two-dimensional nanonet with a leaf-vein-like network structure. The fiber diameter of the two-dimensional nanonet material obtained by this invention exhibits a bimodal distribution, with the nanofiber web having a diameter of 10–50 nm, the polymer short fiber having a diameter of 0.5–2 μm, the pore size of the two-dimensional nanonet being 200–800 nm, and the tensile strength being 5–20 MPa. The leaf-vein-like network structure formed by the oriented arrangement of polymer short fibers can reduce the pore size of the nanofiber web and provide mechanical support, thereby enhancing the filtration and mechanical properties of the material to meet practical application requirements.

[0033] The present invention will now be described in detail with reference to specific embodiments, but this is by no means a limitation thereof. Any preparation methods, materials, structures, or compositional ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0034] Example 1

[0035] The specific steps of the two-dimensional nanonet with a leaf vein-like network structure and its preparation method in this embodiment are as follows:

[0036] Step 1: Dissolve 80g of cellulose in 1000g of N,N-dimethylacetamide, add 5g of cocoyl monoethanolamide, 15g of trimethoxysilane and 40g of polyimide short fibers (0.5μm in diameter and 0.5mm in length), and mechanically stir at 500rpm for 4h to obtain a web-forming mixture;

[0037] Step 2: Select a polyamide electrospun nanofiber membrane as the substrate, with a fiber diameter of 0.6 μm, a pore size of 1 μm, and a thickness of 50 μm;

[0038] Step 3: Select a scraper roller with a diameter of 10mm and a length of 25cm, adjust the scraper roller pressure to 2kg, the speed to 20cm / min, and the film thickness to 20μm, and uniformly coat the above web-laying mixture onto the substrate surface.

[0039] Step 4: Immerse the coated nanofiber substrate in an ultrasonic water bath for phase separation. The phase separation time is 20 min, the phase separation temperature is 20℃, the ultrasonic power is 0.1 kW, and the ultrasonic frequency is 10 kHz. Then dry to obtain an uncrosslinked two-dimensional nanofiber network.

[0040] Step 5: Perform gradient temperature crosslinking treatment on the uncrosslinked two-dimensional nanofiber network. The starting temperature is 20℃, the temperature is increased to 80℃ and held for 20 min, and the temperature is increased to 120℃ and held for 40 min. The heating rate is 5℃ / min. Finally, a two-dimensional nanofiber network with a leaf vein network structure is obtained, with a pore size of 200 nm and a tensile strength of 6.5 MPa. The diameter of the nanofiber network is 40 nm.

[0041] Example 2

[0042] The specific steps of the two-dimensional nanonet with a leaf vein-like network structure and its preparation method in this embodiment are as follows:

[0043] Step 1: Dissolve 10g of polyacrylonitrile in 500g of N,N-dimethylformamide, add 1g of sodium dodecyl sulfate, 10g of isocyanate and 8g of polypropylene short fibers (diameter 2μm, length 3mm), and mechanically stir at 1500rpm for 4h to obtain a web-forming mixture.

[0044] Step 2: Select cellulose filter paper as the substrate, with a fiber diameter of 1.5μm, a pore size of 5μm, and a thickness of 50μm;

[0045] Step 3: Select a scraper roller with a diameter of 10mm and a length of 25cm, adjust the scraper roller pressure to 2kg, the speed to 20cm / min, and the film thickness to 20μm, and uniformly coat the above web-laying mixture onto the surface of the nanofiber substrate.

[0046] Step 4: Immerse the coated nanofiber substrate in an ultrasonic ethanol bath for phase separation. The phase separation time is 30 min, the phase separation temperature is 40℃, the ultrasonic power is 0.5 kW, and the ultrasonic frequency is 50 kHz. Then dry to obtain an uncrosslinked two-dimensional nanofiber network.

[0047] Step 5: Perform gradient temperature crosslinking treatment on the uncrosslinked two-dimensional nanofiber network. The starting temperature is 20℃, the temperature is increased to 60℃ and held for 10 min, the temperature is increased to 100℃ and held for 30 min, and the temperature is increased to 140℃ and held for 30 min. The heating rate is 10℃ / min. Finally, a two-dimensional nanofiber network with a leaf vein network structure is obtained with a pore size of 220 nm and a tensile strength of 20 MPa. The diameter of the nanofiber network is 20 nm.

[0048] Example 3

[0049] The specific steps of the two-dimensional nanonet with a leaf vein-like network structure and its preparation method in this embodiment are as follows:

[0050] Step 1: Dissolve 10g of polyvinylidene fluoride in 1000g of dimethyl sulfoxide, add 3g of monolauryl phosphate, 12g of aziridine and 5g of polyethylene terephthalate short fibers (0.9μm in diameter and 2mm in length), and mechanically stir at 1000rpm for 4h to obtain a web-laying mixture;

[0051] Step 2: Select a substrate of polypropylene spunbond nonwoven fabric with a fiber diameter of 3μm, a pore size of 5μm, and a thickness of 80μm;

[0052] Step 3: Select a scraper roller with a diameter of 8mm and a length of 30cm, adjust the scraper roller pressure to 3kg, the speed to 15cm / min, and the film thickness to 10μm, and uniformly coat the above web-laying mixture onto the surface of the nanofiber substrate.

[0053] Step 4: Immerse the coated nanofiber substrate in an ultrasonic water bath for phase separation. The phase separation time is 20 min, the phase separation temperature is 30℃, the ultrasonic power is 0.5 kW, and the ultrasonic frequency is 80 kHz. Then dry to obtain an uncrosslinked two-dimensional nanofiber network.

[0054] Step 5: Perform gradient temperature crosslinking treatment on the uncrosslinked two-dimensional nanofiber network. The starting temperature is 30℃, the temperature is increased to 60℃ and held for 30 min, and the temperature is increased to 100℃ and held for 30 min. The heating rate is 1℃ / min. Finally, a two-dimensional nanofiber network with a leaf vein network structure is obtained with a pore size of 800nm ​​and a tensile strength of 11MPa. The diameter of the nanofiber network is 100nm.

[0055] Example 4

[0056] The specific steps of the two-dimensional nanonet with a leaf vein-like network structure and its preparation method in this embodiment are as follows:

[0057] Step 1: Dissolve 5g of polyvinylidene fluoride in 400g of N-methylpyrrolidone, add 2g of monododecyltrimethylammonium bromide, 8g of aziridine and 4g of polyimide short fibers (diameter 1.8μm, length 2.5mm), and mechanically stir at 700rpm for 4h to obtain a web-laying mixture;

[0058] Step 2: Select a silica electrospun nanofiber membrane as the substrate, with a fiber diameter of 0.6 μm, a pore size of 3 μm, and a thickness of 10 μm;

[0059] Step 3: Select a scraper roller with a diameter of 8mm and a length of 30cm, adjust the scraper roller pressure to 3kg, the speed to 15cm / min, and the film thickness to 10μm, and uniformly coat the above web-laying mixture onto the surface of the nanofiber substrate.

[0060] Step 4: Immerse the coated nanofiber substrate in an ultrasonic methanol bath for phase separation. The phase separation time is 10 min, the phase separation temperature is 30℃, the ultrasonic power is 0.6 kW, and the ultrasonic frequency is 30 kHz. Then dry to obtain an uncrosslinked two-dimensional nanofiber network.

[0061] Step 5: Perform gradient temperature crosslinking treatment on the uncrosslinked two-dimensional nanofiber network. The starting temperature is 20℃, the temperature is increased to 100℃ and held for 30 min, and the temperature is increased to 150℃ and held for 30 min. The heating rate is 2℃ / min. Finally, a two-dimensional nanofiber network with leaf vein network structure is obtained with a pore size of 500nm and a tensile strength of 12MPa. The diameter of the nanofiber network is 30nm.

[0062] Example 5

[0063] The specific steps of the two-dimensional nanonet with a leaf vein-like network structure and its preparation method in this embodiment are as follows:

[0064] Step 1: Dissolve 10g of polystyrene in 600g of N,N-dimethylformamide, add 2g of sodium dodecyl sulfate, 8g of 2,2'-bis[4-(4-maleimide phenoxy)phenyl]propane and 10g of polyethylene short fibers (1μm in diameter and 2mm in length), and mechanically stir at 1200rpm for 4h to obtain a web-forming mixture;

[0065] Step 2: Select a polyester woven fabric as the substrate, with a fiber diameter of 3μm, a pore size of 4.5μm, and a thickness of 70μm;

[0066] Step 3: Select a scraper roller with a diameter of 10mm and a length of 25cm, adjust the scraper roller pressure to 2kg, the speed to 30cm / min, and the film thickness to 20μm, and uniformly coat the above web-laying mixture onto the surface of the nanofiber substrate.

[0067] Step 4: Immerse the coated nanofiber substrate in an ultrasonic water bath for phase separation. The phase separation time is 120 min, the phase separation temperature is 20℃, the ultrasonic power is 0.1 kW, and the ultrasonic frequency is 20 kHz. Then dry to obtain an uncrosslinked two-dimensional nanofiber network.

[0068] Step 5: Perform gradient temperature crosslinking treatment on the uncrosslinked two-dimensional nanofiber network. The starting temperature is 20℃, the temperature is increased to 80℃ and held for 20 min, and the temperature is increased to 120℃ and held for 30 min. The heating rate is 5℃ / min. Finally, a two-dimensional nanofiber network with a leaf vein network structure is obtained with a pore size of 490 nm and a tensile strength of 9.2 MPa. The diameter of the nanofiber network is 50 nm.

[0069] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a two-dimensional nanomesh material having a leaf-vein network structure, characterized by, Includes the following steps: S1: Add polymer short fibers, surfactants and crosslinking agents to the polymer solution, and then mechanically stir at high speed to obtain a web-laying mixture; S2: The web-laying mixture is uniformly coated onto the surface of the nanofiber substrate using a uniformly rotating scraper, thereby forming an ultrathin continuous liquid film on the surface of the nanofiber substrate. S3: The coated nanofiber substrate is immersed in a non-solvent bath of directional ultrasonic vibration. The directional ultrasonic vibration causes the polymer short fibers on the coated nanofiber substrate to be oriented and arranged. Among them, the polymer short fibers with larger diameters form a leaf vein-like structure. At the same time, the liquid film undergoes phase separation in the non-solvent to form a nanofiber network. After drying to remove the liquid phase, an uncrosslinked two-dimensional nanonet with a leaf vein-like network structure is obtained. S4: The uncrosslinked two-dimensional nanonet with a leaf vein-like network structure is thermally crosslinked to allow the crosslinking agent monomer to undergo a crosslinking reaction between the nanofiber network and the polymer short fiber, thereby enhancing the bonding force between the nanofiber network and the polymer short fiber and finally obtaining a two-dimensional nanonet with a leaf vein-like network structure. In S1, the polymer in the polymer solution is selected from one or more of cellulose, polyamide-imide, polyether-imide, polyvinylidene fluoride, polyacrylonitrile, polystyrene, polyamide, polyurethane, and polyvinyl alcohol, and the mass fraction of the polymer in the polymer solution is 0.1~10 wt%. In S1, the polymer short fiber is selected from one or more of polyethylene short fiber, polypropylene short fiber, polytetrafluoroethylene short fiber, polyimide short fiber, polyamide short fiber, and polyethylene terephthalate short fiber. The polymer short fiber has a diameter of 0.5~2μm, a length of 0.5~3mm, and a mass fraction of 0.1~5wt% in the web-laying mixture.

2. The method for preparing a two-dimensional nanomesh material with a leaf vein-like network structure according to claim 1, characterized in that, In S1, the solvent in the polymer solution is selected from ethanol, isobutanol, n-propanol, N , N -Dimethylformamide, N , N -Dimethylacetamide, dimethyl sulfoxide, N 1-Methylpyrrolidone, ethyl acetate, acetone, N -Methylmorpholine- N - One or more of the oxides.

3. The method for preparing a two-dimensional nanomesh material with a leaf vein-like network structure according to claim 1, characterized in that, In S1, the surfactant is selected from one or more of the following: cocoyl monoethanolamide, cocoyl diethanolamide, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, dodecyltrimethylammonium bromide, potassium lauryl ether phosphate, disodium lauryl sulfosuccinate monoester, monolauryl phosphate, fatty alcohol polyoxyethylene ether ammonium sulfate, and lauramidopropyl betaine. In S1, the crosslinking agent is selected from tetraethyl orthosilicate, methyl orthosilicate, trimethoxysilane, isocyanate, aziridine, etc. N , N '-1,4-Phenylidene dimaleimide, N , N One or more of '-(4,4'-methylenediphenyl)bismaleimide and 2,2'-bis[4-(4-maleimide-phenoxy)phenyl]propane; In S1, the rotation speed of the high-speed mechanical stirring is 500~1500 rpm.

4. The method for preparing a two-dimensional nanomesh material with a leaf vein-like network structure according to claim 1, characterized in that, In S2, the scraper roller is made of stainless steel, has a circular cross-section with a diameter of 5~20mm, a length of 10~50cm, a pressure of 0.1~10kg, a speed of 5~100cm / min, and a film thickness of 0.5~100μm.

5. The method for preparing a two-dimensional nanonet material with a leaf vein-like network structure according to claim 1, characterized in that, In S3, the non-solvent is selected from one or more of water, methanol, ethanol, propanol, isobutanol, ethylene glycol, acetone, cresol, and cyclohexane.

6. The method for preparing a two-dimensional nanomesh material with a leaf vein-like network structure according to claim 1, characterized in that, In S3, the direction of the directional ultrasound is parallel to the plane of the substrate, the ultrasonic power is 0.1~1kW, and the ultrasonic frequency is 10~50kHz.

7. The method for preparing a two-dimensional nanomesh material with a leaf vein-like network structure according to claim 1, characterized in that, In S3, the phase separation time is 10~120 min and the phase separation temperature is 20~50℃.

8. The method for preparing a two-dimensional nanomesh material with a leaf vein-like network structure according to claim 1, characterized in that, In S4, the thermal crosslinking heating method is a gradient heating, which goes through multiple heating-holding stages from the initial temperature to the final temperature. The initial temperature is 20~30℃, the final temperature is 100~160℃, the heating rate is 1~10℃ / min, and the holding time is 10~40min.

9. A two-dimensional nanomesh material with a leaf vein-like network structure prepared by the method according to any one of claims 1 to 8, characterized in that, The two-dimensional nanomesh has a bimodal fiber diameter distribution, wherein the fiber diameter of the nanofiber mesh is 10~50nm and the fiber diameter of the polymer short fiber is 0.5~2μm; the pore size of the two-dimensional nanomesh is 200~800nm ​​and the tensile strength is 5~20MPa.