Multifunctional composite nanofiber membrane and preparation method thereof
By preparing core-shell structured nanofiber membranes and combining them with MXene and fluorinated modified silica, the dual requirements of fabric materials in terms of thermal regulation and electromagnetic shielding were met, thereby improving the stability and performance of multifunctional composite nanofiber membranes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG SCI-TECH UNIV
- Filing Date
- 2025-12-19
- Publication Date
- 2026-05-12
AI Technical Summary
Existing fabric materials cannot simultaneously possess both thermal regulation and electromagnetic interference shielding functions, and therefore cannot effectively meet the dual requirements of environmental temperature changes and electromagnetic radiation pollution.
Core-shell structured nanofiber membranes were prepared by coaxial electrospinning. An electromagnetic shielding layer was constructed using MXene material, and a hydrophobic layer was constructed by spraying fluorinated modified silica to protect the MXene. The mechanical properties of the fiber membranes were enhanced by combining PLA and PVDF.
This achievement comprehensively improves the thermal regulation, electromagnetic shielding, and waterproof performance of nanofiber membranes, ensuring the stable encapsulation of phase change materials and the long-term usability of MXene, thus meeting the multifunctional needs of wearable materials.
Smart Images
Figure CN122013439A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nanofiber membrane technology, and more specifically, to a multifunctional composite nanofiber membrane and a method for preparing the membrane. Background Technology
[0002] With the current deterioration of the natural environment, humans often face sudden increases or decreases in ambient temperature in their daily lives. In order to enable humans to maintain a constant body temperature in such changing environments, the demand for fabrics with thermal regulation functions is growing. Therefore, the development of such fabrics with thermal regulation functions is particularly necessary.
[0003] Meanwhile, with the rapid development of electronic technology and the widespread use of electronic products, while human life has become much more convenient, a large amount of electromagnetic radiation pollution has also emerged. This electromagnetic radiation pollution has caused many health problems for humans and interfered with electronic devices. Driven by the urgent need for health protection, people have placed new demands on the performance of related products, and the market demand for products with electromagnetic shielding functions is constantly increasing.
[0004] However, most commercially available fabrics with thermal regulation functions currently lack corresponding electronic interference shielding properties. Yet, the dual need for both thermal regulation and electromagnetic interference protection is essential in modern life. Therefore, developing a nanofiber material that combines intelligent thermal regulation and electromagnetic interference shielding has become a crucial issue that urgently needs to be addressed. Summary of the Invention
[0005] The purpose of this invention is to provide a multifunctional composite nanofiber membrane, and also to provide a method for preparing such a multifunctional composite nanofiber membrane by electrospinning. The multifunctional composite nanofiber membrane prepared by this method possesses excellent geothermal regulation, electromagnetic shielding, waterproofing, and good mechanical properties, thus meeting current market demands.
[0006] This method fundamentally solves the problem that polymers cannot directly encapsulate phase change materials, thereby preparing a fiber membrane with a core-shell structure through the method of this invention. This membrane has good stability and realizes the encapsulation of phase change materials.
[0007] Specifically, the present invention adopts the following technical solution: A method for preparing a multifunctional composite nanofiber membrane specifically includes the following steps: Step (1): Prepare a shell spinning solution of 15-17 wt% using polylactic acid (PLA), and simultaneously melt n-octadecane to obtain a core spinning solution. Step (2): Adjust the ambient temperature to 35-40℃, and use electrospinning to obtain a coaxial nanofiber membrane of PLA-encapsulated n-octadecane. Step (3): Prepare a hydrochloric acid solution with a concentration of 9-11 mol / L, then add 40-42 ml of the hydrochloric acid solution to a beaker containing 2-3 g of LiF, and slowly add 2-3 g of Ti3AlC2 while stirring continuously. After mixing thoroughly, place the mixture in a constant temperature water bath and let it stand to react. After the reaction is complete, centrifuge to collect the precipitate, and wash the precipitate with deionized water to ensure that the pH value of the system is stable to 6-7 after washing. Step (4): Disperse the above centrifuged precipitate into water by ultrasonication to obtain a suspension. Maintain the system temperature at about 10-11℃ and continue stirring. Transfer the stirred suspension to a centrifuge tube and centrifuge. Collect the supernatant and treat it with circulating water by ultrasonication to obtain an MXene mixture. Seal it and place it in a vacuum oven to stand so that the mixture separates into upper and lower layers to obtain an upper black MXene solution. Then store it in a refrigerator at 14℃. Then measure 20-60mg of the upper black MXene mixture, disperse it with 5-8ml of ethanol, and then spray it onto the coaxial nanofiber membrane obtained in step (2). Store the obtained product at 14℃. Low temperature can reduce the flow of MXene that has not yet been deposited, so that MXene can be more quickly and completely combined with the nanofiber membrane. Step (5): Fluorinated modified silica is added to a mixed solvent of N,N-dimethylformamide and tetrahydrofuran and dispersed by ultrasonication. Then, a polymer mixture consisting of 15-17 wt% PLA and polyvinylidene fluoride (PVDF) with a total mass of 10 g is added and stirred to obtain a homogeneous spinning solution. Then, electrospinning is performed on the product prepared in step (4) using the homogeneous spinning solution to obtain a three-layer nanofiber membrane, which is a multifunctional composite nanofiber membrane.
[0008] Phase change materials (PCMs) are frequently used in intelligent thermal regulation due to their low cost, safety, environmental friendliness, and simple structure. Common organic PCMs have advantages such as non-corrosiveness and good chemical stability; however, they are prone to solid-liquid phase transitions when the temperature changes, which can lead to leakage risks.
[0009] The coaxial electrospinning method used in this invention can simultaneously spin two materials to form core-shell structured nanofibers, thereby effectively encapsulating PCMs in the nanofibers, avoiding the risk of detachment, and improving the encapsulation efficiency of PCMs.
[0010] In the field of electromagnetic shielding, MXene, as a novel two-dimensional material, possesses characteristics such as high conductivity, lightweight, corrosion resistance, and low density. Its layered stacked structure allows for a larger surface area, enhancing its shielding capability against electromagnetic waves. Spraying MXene onto a fiber membrane substrate using a spray gun can impart electromagnetic shielding effects to the fibers. However, the susceptibility of MXene to oxidation in air and its sensitivity to humidity limit its long-term use. Typically, a hydrophobic layer is constructed to protect the MXene, thereby enabling its long-term operation. This invention cleverly solves this problem using the aforementioned method.
[0011] Furthermore, in step (1), the shell spinning solution is a mixed solvent, which is a mixture of N,N-dimethylformamide and tetrahydrofuran in a mass ratio of 1:1.
[0012] Furthermore, the preparation method of fluorinated modified silica is as follows: Tetramethylsilane and (heptadecyl-1,1,2,2-tetrahydrodecyl)trimethoxysilane were mixed in a molar ratio of 3.6:1 and then added to water for ultrasonic treatment. The solution was then added to a mixture of ethanol and ammonium hydroxide in a volume ratio of 2.5:1 and allowed to stand. The solution was stirred with a glass rod at a constant temperature of 30℃, and then the resulting suspension was centrifuged. The supernatant was discarded, the precipitate was collected, and finally dried in an oven to obtain fluorinated modified silica particles.
[0013] Furthermore, in step (2) of electrospinning, the ratio of the injection speed of the shell spinning solution to that of the core spinning solution is 1:2.5-1:10.
[0014] Furthermore, in step (5), the amount of fluorinated modified silica added to the mixed solvent is 1-5%.
[0015] Furthermore, the coating amount of MXene was 0.952-2.857 mg / cm³. 2 .
[0016] Furthermore, the receiving distance for electrospinning is 18-22cm, and the positive voltage is 18-22KV.
[0017] A multifunctional composite nanofiber membrane was prepared using the method described above.
[0018] Compared with the prior art, the beneficial effects of the present invention are: First, this invention utilizes a combination of coaxial electrospinning, spraying, and uniaxial electrospinning to prepare a multifunctional electrospinned nanofiber membrane with heat regulation, electromagnetic shielding, and waterproofing functions. This method first enables coaxial electrospinning technology to encapsulate a large amount of phase change material from polymers that were originally unable to directly encapsulate phase change material, thus producing fibers with a core-shell structure. Second, by spraying MXene, a continuous electromagnetic shielding layer is constructed, giving the fiber membrane shielding capabilities; Finally, the hydrophobic properties of the fiber membrane were significantly enhanced by adding F-SiO2 to the third layer PLA+PVDF. Materials prepared by electrospinning not only meet the requirements for wearable materials in terms of elongation at break, but also show significant improvements in properties such as hydrophobicity, electromagnetic shielding, and thermal regulation. Attached Figure Description
[0019] Figure 1 This is a process flow diagram of the present invention.
[0020] Figure 2 This is a scanning electron microscope image of the coaxial nanofiber membrane prepared in step (2) of Example 1 of the present invention.
[0021] Figure 3 This is a transmission electron microscope image of the coaxial nanofiber membrane from step (2) of Example 1.
[0022] Figure 4 This is a scanning electron microscope image of the hydrophobic nanofiber membrane obtained in step (4) of Example 1.
[0023] Figure 5 The DSC curve is the three-layer nanofiber membrane obtained in step (5) of Example 1.
[0024] Figure 6 The stress-strain curve of the three-layer nanofiber membrane obtained in step (5) of Example 1 is shown.
[0025] Figure 7 The electromagnetic shielding efficiency is the three-layer nanofiber membrane obtained in step (5) of Example 1.
[0026] Figure 8 It is the hydrophobic angle of the three-layer nanofiber membrane obtained in step (5) of Example 1.
[0027] Figure 9 The XPS spectrum of the three-layer nanofiber membrane obtained in step (5) of Example 1 is shown.
[0028] Figure 10 This is a cross-sectional SEM image of the three-layer nanofiber membrane obtained in step (5) of Example 1.
[0029] Figure 11 This is a comparison of the DSC curves of the coaxial nanofiber membranes from step (2) of Examples 1 and 2. Figure 12This is a comparison chart of the electromagnetic shielding efficiency of the nanofiber membranes obtained in step (4) of Example 1 and Example 3.
[0030] Figure 13 This is a comparison diagram of the stress-strain curves of the nanofiber membranes obtained in step (4) of Example 1 and Example 4. Detailed Implementation
[0031] The representative embodiments shown in the accompanying drawings will now be further refined. It should be understood that the following description is not intended to limit the embodiments to a single preferred embodiment. Rather, it is intended to cover alternatives, modifications, and equivalents that may be included within the substance and scope of the embodiments defined by the appended claims.
[0032] This invention provides a multifunctional composite nanofiber membrane, such as... Figure 1 As shown, it is prepared according to the following steps: Step (1): Prepare a 15-17 wt% shell spinning solution using PLA with a mixed solvent. The mixed solvent is composed of N,N-dimethylformamide and tetrahydrofuran mixed in a 1:1 mass ratio. At the same time, melt n-octadecane to obtain the core spinning solution. Step (2): Adjust the ambient temperature to 35-40℃, and use electrospinning to obtain a coaxial nanofiber membrane of PLA-encapsulated n-octadecane; wherein, the injection speed ratio of the shell spinning solution to the core spinning solution is 1:2.5-1:10. Step (3): Prepare a hydrochloric acid solution with a concentration of 9-11 mol / L, then add (40-42 ml) of the hydrochloric acid solution to a beaker containing 2-3 g of LiF, and then slowly add 2-3 g of Ti3AlC2 while stirring continuously. After mixing thoroughly, place the mixture in a 35℃ constant temperature water bath and let it stand for 24 h to react. After the reaction is complete, centrifuge to collect the precipitate, and wash the precipitate with deionized water to ensure that the pH value of the system is stable to 6-7 after washing. Step (4): The centrifuged precipitate is ultrasonically dispersed in water to obtain a suspension. The system temperature is maintained at approximately 10-11°C, and stirring is continued. The stirred suspension is transferred to a centrifuge tube and centrifuged. The supernatant is collected, cooled by circulating water, and ultrasonically treated to obtain an MXene mixture. The mixture is sealed and placed in a vacuum oven to allow it to separate into upper and lower layers, resulting in an upper black MXene solution. This solution is then stored in a refrigerator at 14°C. 20-60 mg of the upper black MXene mixture is then measured, dispersed in 5-8 ml of ethanol, and sprayed onto the coaxial nanofiber membrane obtained in step (2). The resulting product is stored at 14°C. The spraying amount of MXene is 0.952-2.857 mg / cm³. 2 ; Step (5): Fluorinated modified silica is added to a mixed solvent of N,N-dimethylformamide and tetrahydrofuran, with the amount of fluorinated modified silica added being 1-5%; after ultrasonic dispersion, a polymer mixture system composed of PLA and polyvinylidene fluoride is added and stirred to obtain a homogeneous spinning solution; then, the homogeneous spinning solution is used to electrospin the product prepared in step (4) to obtain a three-layer nanofiber membrane, which is a multifunctional composite nanofiber membrane; The preparation method of the fluorinated modified silica used is as follows: Tetramethylsilane and (heptadecyl-1,1,2,2-tetrahydrodecyl)trimethoxysilane were mixed at a molar ratio of 3.6:1, and then added to water for ultrasonic treatment for 1 hour. The solution was then added to a mixture of ethanol and ammonium hydroxide at a volume ratio of 2.5:1 and allowed to stand for 30 minutes. The solution was stirred with a glass rod at a constant temperature of 30°C, and then the resulting suspension was centrifuged. The supernatant was discarded, the precipitate was collected, and finally dried in an oven at 50°C to obtain fluorinated modified silica particles.
[0033] In the electrospinning process described above, the receiving distance is 18-22cm and the positive voltage is 18-22KV.
[0034] The following are specific practical preparation examples.
[0035] Example 1: The applicant has prepared a multifunctional composite nanofiber membrane using the following method, the process of which is as follows: Figure 1 As shown: Step (1): A 15wt% shell spinning solution was prepared using PLA with a mixed solvent. The mixed solvent was composed of N,N-dimethylformamide and tetrahydrofuran in a mass ratio of 1:1. At the same time, n-octadecane was melted to prepare the core spinning solution. Step (2): Adjust the ambient temperature to 35℃, and use electrospinning to obtain a PLA-encapsulated n-octadecane coaxial nanofiber membrane; wherein, the injection rate ratio of the shell spinning solution to the core spinning solution is 1:6.67, that is, the shell flow rate is 0.5ml / h and the core flow rate is 0.15ml / h. Step (3): Prepare a hydrochloric acid solution with a concentration of 9 mol / L, then add 40 ml of hydrochloric acid solution to a beaker containing 2 g LiF, and then slowly add 2 g Ti3AlC2 while stirring continuously. After mixing thoroughly, place the mixture in a constant temperature water bath and let it stand to react. After the reaction is complete, centrifuge to collect the precipitate, and wash the precipitate with deionized water to ensure that the pH value of the system is stable to 6 after washing. Step (4): The centrifuged precipitate was ultrasonically dispersed in water to obtain a suspension. The system temperature was maintained at approximately 10°C, and stirring was continued. The stirred suspension was transferred to a centrifuge tube and centrifuged. The supernatant was collected, cooled by circulating water, and ultrasonically treated to obtain an MXene mixture. The mixture was sealed and placed in a vacuum oven to allow it to separate into upper and lower layers, resulting in an upper black MXene solution. This solution was then stored in a refrigerator at 14°C. 40 mg of the upper black MXene mixture was then measured, dispersed in 5 ml of ethanol, and sprayed onto the coaxial nanofiber membrane obtained in step (2). The resulting product was stored at 14°C. The spraying amount of MXene was 1.905 mg / cm³. 2 ; Step (5): Fluorinated modified silica is added to a mixed solvent of N,N-dimethylformamide and tetrahydrofuran, with the amount of fluorinated modified silica added being 3wt%. After ultrasonic dispersion, a polymer mixture consisting of PLA and polyvinylidene fluoride is added and stirred to obtain a homogeneous spinning solution. Then, electrospinning is performed on the product prepared in step (4) using the homogeneous spinning solution to obtain a three-layer nanofiber membrane, which is a multifunctional composite nanofiber membrane. The receiving distance for electrospinning is 18cm, and the positive voltage is 20KV.
[0036] In the above preparation process, the method for preparing fluorinated modified silica used in step (4) is as follows: Tetramethylsilane and (heptadecyl-1,1,2,2-tetrahydrodecyl)trimethoxysilane were mixed at a molar ratio of 3.6:1 and then added to water for ultrasonic treatment. The solution was then added to a mixture of ethanol and ammonium hydroxide at a volume ratio of 2.5:1 and allowed to stand. The solution was stirred with a glass rod at a constant temperature of 30°C, and then the resulting suspension was centrifuged. The supernatant was discarded, the precipitate was collected, and finally dried in an oven to obtain fluorinated modified silica particles.
[0037] Example 2: The applicant prepared a multifunctional composite nanofiber membrane, which differs from Example 1 in that: Step (2): Adjust the ambient temperature to 35℃, and use electrospinning to obtain a PLA-encapsulated n-octadecane coaxial nanofiber membrane; wherein, the injection rate ratio of the shell spinning solution to the core spinning solution is 1:10, that is, the shell flow rate is 0.5 ml / h and the core flow rate is 0.05 ml / h. Other steps are the same as in Example 1.
[0038] The enthalpy of fusion and the enthalpy of crystallization of Example 1 were measured to be 120.43 and 115.21 J / g, respectively, while those of Example 2 were 44.78 and 42.09 J / g, respectively.
[0039] Example 3: The applicant prepared a multifunctional composite nanofiber membrane, which differs from Example 1 in that: Step (4): The centrifuged precipitate was ultrasonically dispersed in water to obtain a suspension. The system temperature was maintained at approximately 10°C, and stirring was continued. The stirred suspension was transferred to a centrifuge tube and centrifuged. The supernatant was collected, cooled by circulating water, and ultrasonically treated to obtain an MXene mixture. The mixture was sealed and placed in a vacuum oven to allow it to separate into upper and lower layers, resulting in an upper black MXene solution. This solution was then stored in a refrigerator at 14°C. 20 mg of the upper black MXene mixture was then measured, dispersed in 5 ml of ethanol, and sprayed onto the coaxial nanofiber membrane obtained in step (2). The resulting product was stored at 14°C. The spraying amount of MXene was 0.952 mg / cm³. 2 The other steps are the same as in Example 1.
[0040] Example 4: The applicant prepared a multifunctional composite nanofiber membrane, which differs from Example 1 in that: Step (5): Fluorinated modified silica is added to a mixed solvent of N,N-dimethylformamide and tetrahydrofuran, with the amount of fluorinated modified silica added being 5 wt%. After ultrasonic dispersion, a polymer mixture consisting of PLA and polyvinylidene fluoride is added, and the mixture is stirred to obtain a homogeneous spinning solution. Then, electrospinning is performed on the product prepared in step (4) using this homogeneous spinning solution to obtain a three-layer nanofiber membrane, which is a multifunctional composite nanofiber membrane. Other steps are the same as in Example 1.
[0041] The performance of the samples prepared in Examples 1-4 was analyzed. First, regarding Example 1, the details are as follows.
[0042] Figure 2 and Figure 3 These are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the coaxial nanofiber membrane prepared in step (2) of Example 1 of this invention. Figure 2 The scanning electron microscope image shows that the prepared coaxial nanofiber membrane is fibrous at the microscopic level. Figure 3 The transmission electron microscope image shows a clear boundary between the shell material and the core material of the coaxial nanofiber membrane, indicating that the core layer is well encapsulated, thus giving the whole structure a core-shell structure. Encapsulating the phase change material with a core-shell structure helps prevent leakage of the phase change material, allowing it to continuously exert its temperature regulation capabilities.
[0043] Figure 4 The third nanofiber membrane obtained in step (5) of Example 1, from Figure 4The fluorinated modified silica (F-SiO2) bonded to the fibers improves the roughness of the fibers and helps increase the contact area between the fiber surface and the air, thereby improving the hydrophobicity of the three-layer nanofiber membrane. The improved hydrophobicity helps protect the MXene material sprayed in step (2), preventing the hygroscopic MXene from contacting water, thus achieving the effect of protecting the MXene layer and ensuring that the MXene layer can continue to play an electromagnetic shielding role for a long time.
[0044] Figure 5 The DSC curve of the multifunctional composite nanofiber membrane obtained in Example 1 is shown below. Figure 5 As can be seen from the data, it has a large peak area, and melting enthalpy and crystallization enthalpy of 111.73 and 107.29 J / g, respectively, indicating its good temperature regulation capability.
[0045] Figure 6 The figure shows the stress-strain curve of the multifunctional composite nanofiber membrane, the final material of Example 1. It can be seen from the figure that it can reach a maximum tensile stress of 2.38 MPa, indicating that it has good mechanical properties.
[0046] Figure 7 To compare the EMI SE performance of step (2) in Example 1 with the final sample, and after the final sample has been placed for 7 days, from... Figure 7 It can be observed that after the treatment in step (5), a hydrophobic layer is obtained on the surface of the sprayed MXene layer. Figure 7 The performance comparison revealed that the EMI SE performance decreased only slightly after 7 days of storage, indicating that the final sample possesses good electromagnetic shielding performance and long-term stability. It also verifies that the hydrophobic layer can protect the sprayed MXene material, solving the problem of MXene's tendency to deliquescence and loss of electromagnetic shielding capability.
[0047] Figure 8 The figure shows the hydrophobic angle of the multifunctional composite nanofiber membrane, the final material of Example 1. As can be seen from the figure, it has good hydrophobicity, indicating that the construction of a protective layer containing PLA, PVDF, and F-SiO2 can isolate MXene from water, thereby solving the defect problem of MXene material.
[0048] Figure 9 The XPS spectra of the coaxial fiber obtained in step (1) of Example 1, the fiber after spraying in step (2), and the final sample of the multifunctional composite nanofiber membrane obtained in step (5) are shown in the figure. It can be seen from the figure that the element binding energy shift in the XPS spectrum is very small, indicating that the structure has a certain antioxidant capacity. This antioxidant capacity can keep the MXene material stable and prevent it from being oxidized, thereby maintaining its electromagnetic shielding ability and extending its service life. It also verifies that the construction of the hydrophobic layer protects the shielding layer and shows the potential for continuous use.
[0049] Figure 10 The image shows a cross-sectional view of the final material obtained in Example 1. It can be seen from the image that the obtained multifunctional composite nanofiber membrane has a distinct multilayer structure on the cross-section, and the sprayed MXene material is completely deposited on the fiber in the lower layer. The SEM image of the cross-section advantageously illustrates that the structure designed in this invention has been successfully prepared.
[0050] A comparison of Example 1 with Examples 2, 3, and 4 is as follows.
[0051] Figure 11 The figures show the DSC curves for Examples 1 and 2. It is clear from the graph that Example 1 has a larger peak area, indicating that the parameters selected in Example 1 have a higher latent heat value.
[0052] Figure 12 The EMI SE curves for Examples 1 and 3 are shown, with EMI SE values of 10.67 and 32.68 dB, respectively, indicating that the coating amount selected in Example 1 has higher electromagnetic shielding performance.
[0053] Figure 13 The stress-strain curves of Example 1 and Example 4 are compared. It can be clearly seen from the figure that Example 1 has higher stress and strain, indicating that Example 1 has better mechanical properties.
[0054] It will be apparent to those skilled in the art that modifications, combinations, and variations can be made to the teachings described above.
Claims
1. A method for preparing a multifunctional composite nanofiber membrane, characterized in that: Specifically, the steps include the following: Step (1): Prepare a shell spinning solution of 15-17 wt% using PLA, and simultaneously melt n-octadecane to obtain a core spinning solution. Step (2): Adjust the ambient temperature to 35-40℃, and use electrospinning to obtain a coaxial nanofiber membrane of PLA-encapsulated n-octadecane. Step (3): Prepare a hydrochloric acid solution with a concentration of 9-11 mol / L, then add 40-42 ml of the hydrochloric acid solution to a beaker containing 2-3 g of LiF, and slowly add 2-3 g of Ti3AlC2 while stirring continuously. After mixing thoroughly, place the mixture in a 35℃ constant temperature water bath and let it stand for 24 h. After the reaction is complete, centrifuge to collect the precipitate, and wash the precipitate with deionized water to ensure that the pH value of the system is stable to 6-7 after washing. Step (4): Disperse the above centrifuged precipitate into water by ultrasonication to obtain a suspension. Maintain the system temperature at about 10-11℃ and continue stirring. Transfer the stirred suspension to a centrifuge tube and centrifuge. Collect the supernatant and treat it with circulating water by ultrasonication to obtain an MXene mixture. Seal it and place it in a vacuum oven to stand so that the mixture separates into upper and lower layers to obtain an upper black MXene solution. Then store it in a refrigerator at 14℃. Then measure 20-60mg of the upper black MXene mixture, disperse it with 5-8ml of ethanol, and then spray it onto the coaxial nanofiber membrane obtained in step (2). Store the obtained product at 14℃. Step (5): Fluorinated modified silica is added to a mixed solvent of N,N-dimethylformamide and tetrahydrofuran, dispersed by ultrasonication, and then a polymer mixture consisting of 15-17 wt% PLA and polyvinylidene fluoride (PVDF) is added with a total mass of 10 g. The mixture is stirred to obtain a homogeneous spinning solution. Then, electrospinning is performed on the product prepared in step (4) using the homogeneous spinning solution to obtain a three-layer nanofiber membrane, which is a multifunctional composite nanofiber membrane.
2. The method for preparing a multifunctional composite nanofiber membrane according to claim 1, characterized in that: In step (1), the shell spinning solution uses a mixed solvent, which is a mixture of N,N-dimethylformamide and tetrahydrofuran in a mass ratio of 1:
1.
3. The method for preparing a multifunctional composite nanofiber membrane according to claim 1, characterized in that: The preparation method of fluorinated modified silica is as follows: Tetramethylsilane and (heptadecyl-1,1,2,2-tetrahydrodecyl)trimethoxysilane were mixed at a molar ratio of 3.6:1 and then added to water for ultrasonic treatment. The solution was then added to a mixture of ethanol and ammonium hydroxide at a volume ratio of 2.5:1 and allowed to stand for 30 minutes. The solution was stirred with a glass rod at a constant temperature of 30℃, and then the resulting suspension was centrifuged. The supernatant was discarded, the precipitate was collected, and finally dried in an oven to obtain fluorinated modified silica particles.
4. The method for preparing a multifunctional composite nanofiber membrane according to claim 1, characterized in that: In step (2) of electrospinning, the ratio of the injection speed of the shell spinning solution to that of the core spinning solution is 1:2.5-1:
10.
5. The method for preparing a multifunctional composite nanofiber membrane according to claim 1, characterized in that: The amount of fluorinated modified silica added to the mixed solvent in step (5) is 1-5%.
6. The method for preparing a multifunctional composite nanofiber membrane according to claim 1, characterized in that: The coating amount of MXene is 0.952-2.857 mg / cm³. 2 .
7. The method for preparing a multifunctional composite nanofiber membrane according to claim 1, characterized in that: The receiving distance for electrospinning is 18-22cm, and the positive voltage is 18-22KV.
8. A multifunctional composite nanofiber membrane, characterized in that: It is prepared by the preparation method described in any one of claims 1-7.