A superhydrophobic two-component nanofiber membrane and its preparation method

Abstract

The present invention relates to a superhydrophobic bicomponent nanofiber membrane and a preparation method thereof, belonging to the technical field of nanofiber membranes. The preparation method of the present invention includes the following steps: S1. Using electrospinning technology to conduct concentric coaxial spinning to prepare first linear triblock copolymer-cellulose fibers and polylactic acid-second linear triblock copolymer fibers, and then preparing the first linear triblock copolymer-cellulose fibers and polylactic acid-second linear triblock copolymer fibers into a bicomponent fiber membrane; S2. Forming linear triblock copolymer microspheres on the bicomponent fiber membrane through electrostatic spraying technology, and then obtaining the superhydrophobic bicomponent nanofiber membrane after heating. By effectively treating waste cotton cloth, extracting cellulose therefrom, and preparing nanofiber membranes using processes such as electrospinning and electrostatic spraying, high-strength superhydrophobic functions and fluffiness and comfort can be achieved, and the fibers are more tightly held together, which can be used to make high-grade clothing and functional fabrics.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanofiber membranes, and particularly relates to a superhydrophobic bicomponent nanofiber membrane and a preparation method thereof. Background Art

[0002] With the growth of the global population and the pursuit of fashion and functionality of textiles, the service life of most clothing has gradually decreased, and the global textile waste rate has been continuously increasing. For the purpose of environmental protection, recycling and reusing these textiles can bring significant economic and social benefits. Recycling waste cotton cloth and extracting cellulose from it, and adding other materials to achieve functionality. At present, the functionality of cellulose is relatively single, and its application in clothing fabrics is limited. Adding superhydrophobic function can achieve multiple functions such as self-cleaning and antibacterial, and crimped fibers can be used for warmth retention and decoration.

[0003] Styrene-ethylene-butene-styrene block copolymer (SEBS) is a triblock styrene copolymer with excellent tensile and rebound properties. Studies have shown that the static contact angle of SEBS fibers can reach up to 142°, and the rolling contact angle is less than 10°. Cellulose fibers have good weaving properties and a large water permeability; polylactic acid fibers have good biocompatibility and low cost. Combining SEBS fibers with degradable polylactic acid and cellulose fibers can realize the concept of green environmental protection and recyclability, and achieve the functionality and diversification of clothing fabrics. Chinese Patent CN 105274732A discloses a preparation method of a highly flexible coaxial structure cellulose acetate-polyimide electrospun nanofiber membrane for oil-water separation. This method is to add PI with good mechanical properties inside CA with poor mechanical properties. Although this method improves the mechanical properties, it does not make good use of the superhydrophobicity of PI itself, but only attaches superhydrophobic function through surface modification. Chinese Patent CN107737529 A discloses a preparation method of a superhydrophobic and oleophobic composite membrane, which uses the electrospinning method to prepare the membrane and modifies the membrane surface by secondary spraying, but does not improve the mechanical properties of cellulose acetate, and the hot pressing treatment may damage the apparent morphology of the microspheres; Chinese Patent CN 114622422A discloses a preparation method of a thermosensitive moisture-permeable composite coating fabric with superhydrophobicity, which can maintain the thermosensitive moisture-permeability comfortable for the human body, but the superhydrophobic performance of this preparation method is not good, and too many chemical reagents are used, which does not conform to the concept of green environmental protection. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a superhydrophobic bicomponent nanofiber membrane and a preparation method thereof. By effectively treating waste cotton cloth, extracting cellulose therefrom, and using processes such as electrospinning and electrostatic spraying to prepare the nanofiber membrane, high-strength superhydrophobic function and fluffy comfort can be achieved, and the fibers are more tightly held together, which can be used for making high-grade clothing and functional fabrics.

[0005] The first object of the present invention is to provide a preparation method of a superhydrophobic bicomponent nanofiber membrane, including the following steps:

[0006] S1. Use electrospinning technology to perform concentric coaxial spinning to prepare a first linear triblock copolymer-cellulose fiber and a polylactic acid-second linear triblock copolymer fiber, and then prepare the first linear triblock copolymer-cellulose fiber and the polylactic acid-second linear triblock copolymer fiber into a bicomponent fiber membrane; the first linear triblock copolymer-cellulose fiber uses a cellulose solution as the core layer and a first linear triblock copolymer solution as the sheath layer; the polylactic acid-second linear triblock copolymer fiber uses a second linear triblock copolymer solution as the core layer and a polylactic acid solution as the sheath layer;

[0007] S2. Form linear triblock copolymer microspheres on the bicomponent fiber membrane obtained in S1 through electrostatic spraying technology, and then obtain the superhydrophobic bicomponent nanofiber membrane after heating.

[0008] In an embodiment of the present invention, in S1, the concentration of the cellulose solution is 70 g / L - 90 g / L; the solvent of the cellulose solution is dichloromethane and acetone;

[0009] The mass fraction of the first linear triblock copolymer solution is 12% - 13%; the solvent of the first linear triblock copolymer solution is chloroform and toluene, because chloroform will volatilize to form a porous structure, which is beneficial to heat preservation and enhancing hydrophobic performance.

[0010] The mass fraction of the second linear triblock copolymer solution is 13% - 15%; the solvent of the second linear triblock copolymer solution is tetrahydrofuran;

[0011] The mass fraction of the polylactic acid solution is 9% - 11%; the solvent of the polylactic acid solution is N,N-dimethylformamide and dichloromethane.

[0012] In an embodiment of the present invention, in S1, the cellulose is obtained by washing, bleaching, activating, and extracting waste cotton cloth.

[0013] In one embodiment of the present invention, a bicomponent fiber membrane is prepared by using the concentric channels in the concentric gourd-shaped electrospinning nozzle and the gourd-shaped nozzle in the concentric gourd-shaped electrospinning nozzle to respectively prepare a first linear triblock copolymer and cellulose fibers, polylactic acid, and a second linear triblock copolymer fiber.

[0014] In one embodiment of the present invention, the sizes of the core layer and the sheath layer in the concentric gourd-shaped electrospinning nozzle are independently 17G - 18G and 22G - 25G.

[0015] In one embodiment of the present invention, the spinning speeds in the concentric gourd-shaped electrospinning nozzle are 0.8 mL / h - 1 mL / h and 1.5 mL / h - 2 mL / h respectively.

[0016] In one embodiment of the present invention, in S2, the process parameters of the electrostatic spraying are: the feeding rate is 1 mL / h - 1.5 mL / h, the spraying voltage is 18 kV - 22 kV, the collection distance is 15 cm - 18 cm, and the electrostatic spraying time is 10 min - 30 min.

[0017] Further, in S2, a 24G flat orifice spinneret is used for the electrostatic spraying.

[0018] In one embodiment of the present invention, in S2, the solution used for preparing the linear triblock copolymer microspheres is a mixed solution of a linear triblock copolymer, tetrahydrofuran, and N,N-dimethylformamide. The mass fraction of the linear triblock copolymer in the mixed solution is 7% - 9%. The microspheres do not need to form a porous structure. SEBS is a triblock copolymer containing a PS phase and a PEB phase. For this solvent system of THF and DMF, where THF is a good solvent for both PS and PEB, while DMF is a good solvent for PS and a poor solvent for PEB, so THF and DMF constitute a selective solvent system.

[0019] Further, the volume ratio of tetrahydrofuran (THF) to N,N-dimethylformamide (DMF) is 4:1. Although the spinning solution concentration of THF / DMF = 80 / 20 is relatively high, due to the microphase separation of the block copolymer SEBS in this selective solvent system of THF and DMF, the entanglement between molecular chains is very small, thus forming linear triblock copolymer microspheres (SEBS microspheres).

[0020] In one embodiment of the present invention, in S2, the particle size of the linear triblock copolymer microspheres is 3 μm - 5 μm.

[0021] In one embodiment of the present invention, in S2, the heating temperature is 180°C - 200°C and the time is 1 h - 1.5 h.

[0022] The second object of the present invention is to provide a superhydrophobic bicomponent nanofiber membrane prepared by the described method.

[0023] In one embodiment of the present invention, the pore size on the surface of the linear triblock copolymer porous fibers formed by the sheath solution in the first linear triblock copolymer-cellulose fibers is 30 nm - 900 nm.

[0024] In one embodiment of the present invention, the pore size on the surface of the polylactic acid porous fibers formed by the sheath solution in the polylactic acid - second linear triblock copolymer fibers is 300 nm - 800 nm.

[0025] In one embodiment of the present invention, the formation of nano-scale pores generates a large number of air cushions, preventing water droplets from wetting, increasing the static contact angle of the fibers, improving the surface roughness of the fibers, and enhancing the hydrophobic property. Hydrophobic polymers are electrospun into porous structures in volatile organic solvents because during the rapid evaporation of the solvent, the solution generates thermodynamic instability, resulting in the original single phase being divided into two phases, namely the polymer-rich phase and the polymer-deficient phase, which respectively form fiber scaffolds and pores after curing.

[0026] The technical solution of the present invention has the following advantages compared with the prior art:

[0027] (1) In the preparation method of the present invention, cellulose is extracted from waste cotton cloth and combined with the superhydrophobic material SEBS to form concentric first linear triblock copolymer-cellulose fibers; PLA containing a large number of hydrophobic groups is combined with SEBS to form concentric polylactic acid - second linear triblock copolymer fibers; a concentric gourd-shaped electrospinning nozzle is used to form a bicomponent fiber membrane, and SEBS microspheres are electrostatically sprayed on the bicomponent fiber membrane to increase the surface roughness of the fiber membrane and its hydrophobicity.

[0028] (2) The preparation method of the present invention uses cellulose and SEBS for concentric electrospinning, combining the advantages of both, which not only endows the fibers with excellent mechanical properties but also makes the fibers soft and breathable. PLA fibers and SEBS itself are excellent superhydrophobic materials. The evaporation of the solvent causes pores to form on the surfaces of the two fibers. Such nano-scale pores can effectively hold up water droplets and achieve moisture absorption and sweat discharge. The concentric electrospinning of PLA and SEBS ensures that even when water droplets pass through the pores, they will be blocked by the internal SEBS fibers. Since SEBS and PLA fibers as the sheath layers have different solubilities, curly fibers can be obtained, increasing warmth retention and fluffiness, and making the hand feel more comfortable.

[0029] (3) In the preparation method of the present invention, SEBS microspheres are electrostatically sprayed on the fiber membrane, which can simulate the micron-scale conical protrusions on the lotus leaf surface. According to the Cassie-Baxter model theory, the air cushion formed by the air wrapped by these rough structures will support the water droplets and prevent them from wetting the surface. Since the same hydrophobic polymer, the superhydrophobic performance of its electrosprayed microspheres is often better than that of its electrospun fibers. Therefore, when SEBS microspheres are electrosprayed on SEBS fibers, the superhydrophobic performance is more excellent. Even if some SEBS microspheres penetrate through the PLA fiber holes on the surface of the PLA-SEBS fiber, they can effectively adhere to the surface of the SEBS fiber. Through the high-temperature calcination and annealing treatment in a vacuum tube furnace, good adhesion is generated between the SEBS microspheres and the fiber membrane, making it more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to the specific embodiments of the present invention and in combination with the drawings, where:

[0031] Figure 1 is a schematic diagram of the device for preparing the SEBS-cellulose / PLA-SEBS fiber membrane of the present invention;

[0032] Figure 2 is an enlarged schematic diagram of the concentric gourd-shaped electrospinning nozzle of the present invention;

[0033] Figure 3 is a schematic diagram of the device for preparing SEBS microspheres of the present invention;

[0034] Description of reference numerals: 1 - SEBS / chloroform / toluene solution, 2 - cellulose / DCM / acetone solution, 3 - SEBS / THF solution, 4 - PLA / DMF / DCM solution, 5 - concentric gourd-shaped electrospinning nozzle, 51 - concentric gourd-shaped electrospinning nozzle orifice, 511 - gourd-shaped nozzle, 512 - partition channel, 513 - concentric inner orifice, 6 - SEBS-cellulose fiber, 7 - PLA-SEBS fiber, 8 - SEBS-cellulose / PLA-SEBS fiber membrane, 9 - SEBS / THF / DMF solution, 10 - SEBS microspheres, 11 - composite microsphere fiber membrane. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following further illustrates the present invention in combination with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention.

[0036] In the present invention, unless otherwise specified, the method for extracting cellulose specifically includes the following steps: first, wash the waste cotton cloth, and then perform bleaching treatment. The cotton cloth is subjected to oxygen bleaching treatment using 20 mL / L of H2O2 (hydrogen peroxide), with the temperature set at 95 °C, the time being 100 min, and the pH value being 10; the dosage of Na2SiO3 (sodium silicate) is 2 g / L, the penetrant is 2 g / L, and the liquor ratio is 1:20. Activate the bleached cotton cloth. Immerse every 5 g of the cotton cloth in a 20% sodium hydroxide solution for ultrasonic treatment. The mass ratio of the fabric to the solvent is 1:10, the mass fraction of [Amim]Cl (1-allyl-3-methylimidazolium chloride) is 99%, the process temperature is 85 °C, the dissolution time is 4 h, and the ultrasonic treatment time is 1 h. Disassemble the fabric into yarns and dissolve them in the ionic solvent [Amim]Cl (1-allyl-3-methylimidazolium chloride). The dissolution temperature is 95 °C, the dissolution time is 5.5 h, the mass fraction of [Amim]Cl is 99%, and the mass ratio of the solute to the solvent is 1:17.5. Separate the solvent from the cellulose solute by means such as suction filtration, drying, and centrifugation of the dissolution solution, and grind the recovered cellulose solid into powder.

[0037] In the present invention, unless otherwise specified, the experimental methods used are all conventional methods without special instructions, and the materials, reagents, etc. used can all be obtained from commercial channels without special instructions.

[0038] In the present invention, unless otherwise specified, the preparation of the superhydrophobic double-component nanofiber membrane is carried out by Figure 2 the concentric gourd-shaped electrospinning nozzle 5 shown. The concentric gourd-shaped electrospinning nozzle 5 is composed of two concentric electrospinning nozzles arranged side by side. It can be seen from the concentric gourd-shaped electrospinning nozzle orifice 51 that the cross-section of the nozzle orifice is gourd-shaped. Among them, the size of the gourd-shaped nozzle 511 is 17-18G, the size of the concentric inner nozzle orifice 513 is 22-25G, and there is a partition 512 in the center of the concentric gourd-shaped electrospinning nozzle 5.

[0039] In the present invention, unless otherwise specified, all raw materials are commercially available or prepared by conventional methods in the art; waste cotton cloth is from Dali (China) Co., Ltd.; hydrogen peroxide solution is purchased from Youtepu Technology Suzhou Co., Ltd., product number 750220204; sodium silicate is purchased from Youtepu Technology Suzhou Co., Ltd., CAS number 13517-24-3; penetrant is purchased from Jiangsu Argon Krypton Xenon Materials Technology Co., Ltd., CAS number 1639-66-3; sodium hydroxide solution is purchased from Youtepu Technology Suzhou Co., Ltd., CAS number 1310-73-2; 1-allyl-3-methylimidazolium chloride is purchased from Shandong Tianlong Chemical Co., Ltd., CAS number 1344-09-8; dichloromethane is purchased from Youtepu Technology Suzhou Co., Ltd., CAS number 75-09-2; acetone is purchased from Yonghua Chemical Technology (Jiangsu) Co., Ltd., CAS number 67-64-1; chloroform is purchased from Zancheng (Tianjin) Technology Co., Ltd., CAS number 865-49-6; toluene is purchased from Yonghua Chemical Technology (Jiangsu) Co., Ltd., CAS number 108-88-3; triblock copolymer polystyrene-b-poly(ethylene-co-butene)-b-polystyrene is purchased from US Kraton Corporation, CAS number FG1901; tetrahydrofuran is purchased from Jiangsu Argon Krypton Xenon Materials Technology Co., Ltd., CAS number 109-99-9; N,N-dimethylformamide is purchased from Youtepu Technology Suzhou Co., Ltd., CAS number 68-12-2; polylactic acid is purchased from Suzhou Great Pharmaceutical Technology Co., Ltd., CAS number 26100-51-6; dichloromethane is purchased from Youtepu Technology Suzhou Co., Ltd., CAS number 75-09-2.

[0040] Example 1

[0041] Refer to Figures 1-3 As shown, the superhydrophobic bicomponent nanofiber membrane and its preparation method of the present invention specifically include the following steps:

[0042] S1. Preparation of solutions

[0043] SEBS / chloroform / toluene solution 1: Prepare a spinning solution according to a mass ratio concentration of 3:5:16, and stir magnetically at room temperature for 26 h;

[0044] Cellulose / DCM / acetone solution 2: Cellulose is dissolved in a mixed solution of DCM and acetone with a volume ratio of 2:1.2, and the concentration of cellulose is 80 g / L;

[0045] SEBS / THF solution 3: Dissolve SEBS in THF, and stir magnetically at room temperature for 20 h. The mass fraction of SEBS is 14%.

[0046] PLA / DMF / DCM solution 4: Add PLA to a mixed solution of DMF and DCM with a volume ratio of 4:1. The mass fraction of PLA is 10%.

[0047] S2. Use the electrospinning technique to perform concentric coaxial electrospinning to prepare SEBS-cellulose fibers 6 and PLA-SEBS fibers 7, and then prepare the SEBS-cellulose / PLA-SEBS fiber membrane 8 from the SEBS-cellulose fibers 6 and PLA-SEBS fibers 7;

[0048] For the SEBS-cellulose fibers 6, use a cellulose / DCM / acetone solution as the core layer and an SEBS / chloroform / toluene solution as the sheath layer. The spinning nozzles for the sheath layer and the core layer are 18G / 25G in size respectively, the spinning voltage is 30 kV, the collection distance is 20 cm, and the feeding rates of the core-sheath solutions are 1 mL / h and 1.5 mL / h respectively;

[0049] For the PLA-SEBS fibers 7, use an SEBS / THF solution as the core layer and a PLA / DMF / DCM solution as the sheath layer. The spinning nozzles for the sheath layer and the core layer are 18G / 25G in size respectively, the spinning voltage is 20 kV, the collection distance is 20 cm, and the feeding rates of the core-sheath solutions are 1 mL / h and 1.5 mL / h respectively.

[0050] S3. Form SEBS microspheres 10 on the SEBS-cellulose / PLA-SEBS fiber membrane 8 through the electrostatic spraying technique (the used SEBS / THF / DMF solution 9 is a mixed solution of SEBS, THF, and DMF, with the mass fraction of SEBS being 8%, and the volume ratio of THF to DMF being 4:1). Then, heat it in a vacuum tube furnace at 180 °C for 1.5 h and anneal for 3 h to obtain the composite microsphere fiber membrane 11; during electrostatic spraying, use a 24G flat nozzle, the feeding rate of the syringe pump is 1.5 mL / h, the spraying voltage is 22 kV, the collection distance is 15 cm, the electrostatic spraying time is 30 min, the ambient temperature is 27 ± 2 °C, the ambient humidity is about RH 35%, and the set speed of the roller rotation is 2500 r / min.

[0051] Example 2

[0052] Basically the same as Example 1, the only difference is that: the electrostatic spraying time is 10 min.

[0053] Example 3

[0054] Basically the same as Example 1, the only difference is that: the electrostatic spraying time is 20 min.

[0055] Comparative Example 1

[0056] Basically the same as Example 1, the only difference is that: during electrospinning, use an ordinary single-axis needle and only use the SEBS solution for electrospinning.

[0057] Comparative Example 2

[0058] Basically the same as Example 1, the only difference is that: the concentric gourd-shaped electrospinning nozzle is changed to one side without the concentric needle structure, and only PLA solution and SEBS solution are used for concentric electrospinning, and the cellulose fibers are electrospun separately.

[0059] Comparative Example 3

[0060] Basically the same as Example 1, the only difference is that: the concentric gourd-shaped electrospinning nozzle is changed to one side without the concentric needle structure, and only SEBS solution and cellulose solution are used for concentric electrospinning, and the SEBS fibers are electrospun separately.

[0061] Comparative Example 4

[0062] Basically the same as Example 1, the only difference is that: the concentric gourd-shaped electrospinning nozzle is changed to both sides without the concentric needle structure, and only PLA solution and SEBS solution are used for side-by-side electrospinning.

[0063] Comparative Example 5

[0064] Basically the same as Example 1, the only difference is that: the concentric gourd-shaped electrospinning nozzle is changed to a concentric electrospinning nozzle, and only SEBS solution and cellulose solution are used for concentric electrospinning.

[0065] Comparative Example 6

[0066] Basically the same as Example 1, the only difference is that: the concentric gourd-shaped electrospinning nozzle is changed to a concentric electrospinning nozzle, and only PLA solution and SEBS solution are used for concentric electrospinning.

[0067] Comparative Example 7

[0068] Basically the same as Example 1, the only difference is that: no electrostatic spraying of SEBS microspheres is carried out.

[0069] Test Example

[0070] The hydrophobicity performance test, breaking strength test, flushing performance test, and surface roughness performance test were carried out on the fibers prepared in Examples 1-3 and Comparative Examples 1-7. The test methods or standards are as follows:

[0071] (1) Hydrophobicity performance test: According to the national standards "GB / T 42270-2022 Test method for hydrophobicity of porous hydrophobic membranes" and "GB / T 30447-2013 Measurement method for contact angle of nanofilm", about 4 μL of deionized water droplets were used, and the droplet flow rate was 0.5 μL / s. An optical contact angle tester was used to observe the static contact angle and rolling contact angle of the deionized water droplets in contact with the film. Five positions of each film were measured. After the measurement, the data of the fiber film was calculated to obtain the average value and standard deviation.

[0072] (2) Tensile fracture strength test: At least 5 specimens were cut from the samples according to the method of the international standard "ISO 9073-3-1989 Textiles - Test methods for nonwovens - Part 3: Determination of tensile strength and elongation" to measure the fracture strength of the electrospun film with composite structure.

[0073] (3) Flushing performance test: A flushing experiment was carried out on the composite fiber membrane. The composite nanofiber membrane was continuously flushed with a fast water flow (1.3 m 3 / s) for 200 h, and the static contact angle and rolling contact angle of the composite nanofiber membrane were observed.

[0074] (4) Surface roughness test: The 3D surface topography of the fiber membrane was analyzed using a BMT Expert surface topography analyzer. The surface scanning mode was adopted, the scanning area was 3 mm × 3 mm, the scanning speed was 1 mm / s, and the accuracy was 300 points / mm. After the scanning was completed, the surface roughness of the scanning area was calculated according to the relative height of each position of the sample.

[0075] The results of the above performance tests are shown in Table 1-2 as follows:

[0076] Table 1

[0077]

[0078]

[0079] As can be seen from Table 1, with the increase of the electrostatic spraying time, the density of microspheres on the fiber membrane becomes larger and larger, the static contact angle of the composite fiber membrane increases significantly, while the rolling contact angle gradually becomes smaller. Around 20 min - 30 min, the change of the rolling contact angle of the composite fiber membrane tends to be stable. After continuous flushing, although the microspheres on the surface of the composite fiber membrane are washed away by the fluid, the change is not very large, indicating that the microspheres are relatively stable on the composite fiber membrane. Through the above comparative examples, it can be seen that compared with the combination methods such as concentric and juxtaposed of various fiber materials, the combination method of Example 1 can achieve better superhydrophobic performance. Especially the implementation method of the double-component concentric fiber can enhance the mechanical properties of cellulose fibers, making the fiber membrane have the strength applicable to clothing.

[0080] Table 2

[0081] specimen Example 1 Example 2 Example 3 Surface roughness / μm 23.9 15.8 11.2

[0082] As can be seen from Table 2, with the extension of the electrostatic spraying time, the surface roughness of the composite fiber membrane can reach the maximum at 20 min. The larger the surface roughness, the smaller the contact area between the fiber and the water droplet, and the better the superhydrophobic performance.

[0083] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A preparation method of a superhydrophobic two-component nanofiber membrane, characterized in that, Comprising the following steps, S1. Using electrospinning technology to perform concentric coaxial electrospinning to prepare first linear triblock copolymer-cellulose fibers and polylactic acid-second linear triblock copolymer fibers, and then preparing the first linear triblock copolymer-cellulose fibers and polylactic acid-second linear triblock copolymer fibers into a bicomponent fiber membrane; the first linear triblock copolymer-cellulose fibers use a cellulose solution as the core layer and a first linear triblock copolymer solution as the sheath layer; the polylactic acid-second linear triblock copolymer fibers use a second linear triblock copolymer solution as the core layer and a polylactic acid solution as the sheath layer; the first linear triblock copolymer and the second linear triblock copolymer have superhydrophobicity; S2. Forming linear triblock copolymer microspheres on the bicomponent fiber membrane obtained in S1 by electrostatic spraying technology, and then obtaining the superhydrophobic bicomponent nanofiber membrane through heating.

2. The preparation method of the superhydrophobic two-component nanofiber membrane according to claim 1, wherein In S1, the concentration of the cellulose solution is 70 g / L - 90 g / L; the solvent of the cellulose solution is dichloromethane and acetone; The mass fraction of the first linear triblock copolymer solution is 12% - 13%; the solvent of the first linear triblock copolymer solution is chloroform and toluene; The mass fraction of the second linear triblock copolymer solution is 13% - 15%; the solvent of the second linear triblock copolymer solution is tetrahydrofuran; The mass fraction of the polylactic acid solution is 9% - 11%; the solvent of the polylactic acid solution is N,N-dimethylformamide and dichloromethane.

3. The preparation method of the superhydrophobic bicomponent nanofiber membrane according to claim 1, characterized in that, In S1, the cellulose is obtained by washing, bleaching, activating, and extracting waste cotton cloth.

4. The preparation method of the superhydrophobic two-component nanofiber membrane according to claim 1, characterized in that, Through the concentric channels in the concentric gourd-shaped electrospinning nozzle and the gourd-shaped nozzle in the concentric gourd-shaped electrospinning nozzle, the first linear triblock copolymer and cellulose fibers, and polylactic acid and second linear triblock copolymer fibers are respectively prepared into a bicomponent fiber membrane.

5. The preparation method of the superhydrophobic bicomponent nanofiber membrane according to claim 1, characterized in that, The sizes of the core layer and the sheath layer in the concentric gourd-shaped electrospinning nozzle are independently 17G - 18G and 22G - 25G.

6. The preparation method of the superhydrophobic two-component nanofiber membrane according to claim 1, characterized in that, The electrospinning speeds in the concentric gourd-shaped electrospinning nozzle are respectively 0.8 mL / h - 1 mL / h and 1.5 mL / h - 2 mL / h.

7. The preparation method of the superhydrophobic two-component nanofiber membrane according to claim 1, characterized in that, In S2, the process parameters of the electrostatic spraying are: the feeding rate is 1 mL / h - 1.5 mL / h, the spraying voltage is 18 kV - 22 kV, the collection distance is 15 cm - 18 cm, and the electrostatic spraying time is 10 min - 30 min.

8. The preparation method of the superhydrophobic bicomponent nanofiber membrane according to claim 1, characterized in that, In S2, the solution used to prepare the linear triblock copolymer microspheres is a mixed solution of linear triblock copolymer, tetrahydrofuran, and N,N-dimethylformamide, and the mass fraction of the linear triblock copolymer in the mixed solution is 7% - 9%.

9. The preparation method of the superhydrophobic two-component nanofiber membrane according to claim 1, characterized in that, In S2, the heating temperature is 180 °C - 200 °C, and the time is 1 h - 1.5 h.

10. The superhydrophobic bicomponent nanofiber membrane prepared by the method according to any one of claims 1 - 9.

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