POM / PVDF (Polyoxymethylene / Polyvinylidene Fluoride) radiation refrigeration composite film based on electrostatic spinning method as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of a POM / PVDF (Polyoxymethylene / Polyvinylidene Fluoride) radiation refrigeration composite film based on an electrostatic spinning method, and belongs to the field of radiation refrigeration materials. Polyvinylidene fluoride is used as a matrix, polyformaldehyde is used as a modification component, and PVDF / POM composite membranes with different proportions are prepared by an electrostatic spinning method, so that a composite membrane material with high solar reflectivity and infrared emissivity is constructed, and the microstructure stability and thermal properties of the composite membrane material are considered; the practical application value is expected to be achieved in the fields of passive cooling and heat management. A characterization technology is comprehensively tested, and the aspects of structure, thermal stability, photo-thermal performance and the like of composite films made of materials with different proportions are researched, so that the passive radiation cooling material with the most excellent performance is obtained. In the future, a fiber structure and a process can be optimized, and an evaporative cooling or phase change technology is combined, so that the practical application is realized, and help is provided for energy conservation and environment regulation and control.

Description

Technical Field

[0001] This invention relates to the field of radiation-cooled polymer thin film materials technology, and in particular to a POM / PVDF radiation-cooled composite film based on electrospinning, its preparation method and application. Background Technology

[0002] Global warming has exacerbated the energy consumption of refrigeration equipment, making the research of new and efficient cooling technologies particularly urgent. Active cooling strategies primarily rely on compression systems, which are bulky, energy-intensive, and dependent on electricity, limiting their application mainly to aerospace and specialized operations. In contrast, passive radiative cooling materials have a higher thermal radiation power than heat input power, enabling them to effectively dissipate their own heat and achieve cooling, showing broad application prospects in high-temperature outdoor environments.

[0003] Passive radiative cooling (PRC) is a passive cooling technology that dissipates heat into outer space through atmospheric windows. It requires no energy consumption, potentially reducing energy and environmental pressures. The key to this technology is that the materials must have high solar reflectivity and high infrared emissivity to ensure effective cooling even under intense sunlight. Radiative cooling textiles, as a key development direction in personal thermal management, can continuously dissipate heat without energy consumption. However, they currently suffer from poor thermal stability, weak mechanical properties, and significant manufacturing difficulties, limiting their widespread application. Therefore, developing radiative cooling textiles that not only possess excellent thermal management performance but also good wearability, ideally at an affordable price, is a crucial and urgent problem to be solved in the field of personal thermal management.

[0004] Solution electrospinning is a widely used process for producing nanofibers, found in both research and industrial production. Electrospinning is performed in an electrostatic field of tens of kilovolts. One electrode is connected to a polymer solution jetting device, on which a syringe is placed; the other electrode is connected to a receiving device, which can be covered with a receiving foil. Under the influence of a certain electric field, polymer droplets overcome surface tension to form a conical structure, known as a "Taylorcone," which is then deposited on the receiving device to form fibers. Electrospinning technology allows for easy control of the composition and properties of the resulting fibers. The preparation process is simple and low-cost, and the obtained fibers possess advantages such as high permeability, high separation efficiency, large specific surface area, and adjustable wettability.

[0005] In recent years, some novel polymer materials, such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and polyoxymethylene (POM), have attracted in-depth research from scholars in the field of radiation cooling materials due to their excellent emissivity and other properties. The CF bond vibrations in PVDF molecules give them high infrared emissivity in the 8–13 μm and 16–20 μm atmospheric window bands, releasing heat into space as infrared radiation. The vibrational absorption and emission wavelengths of POM are mainly distributed within the atmospheric window (8–13 μm), making it a potential raw material for developing radiation-cooled textiles. Wu et al. designed a POM nanotextile that employs an adaptive heat dissipation mechanism between emission and transmission modes to achieve environmentally independent human body cooling. Crucially, the POM textile exhibits a selective emissivity of 75.7% in the 8–13 μm band, a transmittance of 48.5% in the 4–25 μm band, and a solar reflectance of 94.6% in the 0.3–2.5 μm band, demonstrating significantly enhanced radiation-cooling performance in sunny outdoor, cloudy outdoor, and indoor environments. Currently, there is no research or application of POM and PVDF composite spinning materials for radiative cooling in the market, therefore, it has great application prospects in the field of human body thermal management. Summary of the Invention

[0006] The first objective of this invention is to provide a POM / PVDF radiation-cooling composite membrane based on electrospinning. Using polyvinylidene fluoride as the matrix and polyoxymethylene as the modifying component, electrospinning is performed to obtain a micro / nano-sized fiber membrane with a porous structure, which can achieve a strong Mie scattering effect on solar wavelengths, effectively enhancing the material's radiation-cooling performance.

[0007] The second objective of this invention is to provide a method for preparing the aforementioned POM / PVDF radiation-cooling composite membrane based on electrospinning. POM is used as a modifier to regulate the structure and properties of PVDF, and the composite membrane is fabricated using electrospinning technology. Furthermore, its microstructure, thermal properties, and infrared emission behavior are systematically studied and investigated, providing a new approach and pathway for the design and application of high-performance radiation-cooling materials. This invention also provides a method for preparing polymer radiation-cooling composite membranes based on electrospinning.

[0008] The third objective of this invention is to provide the application of the aforementioned POM / PVDF radiation cooling composite membrane based on electrospinning in the field of human body thermal management.

[0009] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0010] A POM / PVDF radiative cooling composite membrane based on electrospinning is disclosed. Its raw materials include polyvinylidene fluoride (PVDF), polyoxymethylene (POM), and the solvent hexafluoroisopropanol (HFIP). PVDF serves as the matrix, providing the main component for electrospinning the fiber membrane, while POM acts as a modifier to adjust the radiative cooling performance of the composite material. HFIP dissolves many important polymers that are difficult to dissolve in other solvents, producing high-quality, smooth, uniform, bead-free or low-bead nanofibers. It exhibits good volatility, rapid fiber curing, and is suitable for various polymer systems, especially as a "gold standard" solvent in the field of water treatment biomaterials, ensuring stable fiber formation.

[0011] The solvent chosen is hexafluoroisopropanol (HFIP), which can dissolve a variety of poorly soluble polymers. It has good solubility for PVDF and POM. Moreover, HFIP is easily volatile at room temperature, which allows the solvent to evaporate quickly during electrospinning, promoting fiber solidification and reducing fiber adhesion, thus forming a uniform nanofiber structure.

[0012] This technical approach is based on three main aspects, as described below:

[0013] 1. Add polyvinylidene fluoride (PVDF) to the solvent hexafluoroisopropanol (HFIP) and let it dissolve continuously by stirring.

[0014] 2. After dissolving polyvinylidene fluoride (PVDF) in the solvent, add polyoxymethylene (POM) and further stir using a magnetic stirrer to ensure that it is evenly distributed in the spinning solution and fully and evenly combined with the PVDF component.

[0015] 3. The initially obtained spinning solution is subjected to electrospinning, in which the electrospinning parameters (including spinning distance, positive and negative high voltage, needle diameter, etc.) are adjusted to obtain a radiation-cooling electrospun membrane with optimal radiation cooling performance.

[0016] A method for preparing a POM / PVDF radiation-cooling composite membrane based on electrospinning, the specific steps of which are as follows:

[0017] Step 1: Before the experiment begins, calculate the amount of experimental raw materials required for each ratio and weigh the experimental raw materials using an electronic balance: solvent hexafluoroisopropanol (HFIP), polyvinylidene fluoride (PVDF), and polyoxymethylene (POM).

[0018] Step 2: Add polyvinylidene fluoride (PVDF) powder to hexafluoroisopropanol HFIP solvent and stir to fully dissolve the PVDF powder in the solution. Gradually add POM powder to the initially obtained PVDF solution and then use a magnetic stirrer to mix the two completely and evenly. After stirring for a period of time, ultrasonically treat the spinning solution.

[0019] Step 3: Electrospin the obtained spinning solution, adjust the appropriate spinning parameters so that the droplets at the needle tip can stably form Taylor cones under the action of the electric field, and stack at the receiving end to form a fiber membrane.

[0020] Step 4: After spinning is completed, the aluminum foil at the receiving end is removed, placed at room temperature for more than 24 hours, and then subjected to low-temperature drying treatment. Finally, the performance of the film material is characterized and analyzed.

[0021] The polyvinylidene fluoride (PVDF) (purity > 99%), polyoxymethylene (POM) (purity > 99%), and hexafluoroisopropanol (HFIP) (purity > 99%) solvents in step 1 have a total polymer concentration of 10%.

[0022] The concentration of polyvinylidene fluoride (PVDF) in step 2 is 5%, and the mass ratio of polyoxymethylene (POM) to polyvinylidene fluoride (PVDF) is 1:1.

[0023] In step 2, use a magnetic stirrer with a speed of 500 r / min, a stirring temperature of room temperature (25℃), and a stirring time of at least 12 hours.

[0024] The parameters for electrospinning in step 3 are as follows: the spinning needle is No. 18 to No. 22, the spinning distance (the distance between the needle and the collecting device) is 80 to 200 mm, the spinning temperature is room temperature (25℃), the spinning voltage is 8 to 15 kV, the spinning speed is 0.1 to 0.4 mm / min, and the relative humidity of the air is 30% to 50%.

[0025] The preferred spinning needle is No. 20.

[0026] The preferred electrospinning distance is 180 mm.

[0027] The preferred spinning voltage is 12kV.

[0028] The preferred spinning speed is 0.2 mm / min.

[0029] The preferred relative humidity of the air is 40%.

[0030] The application of the POM / PVDF radiation cooling composite membrane based on electrospinning in the field of human body thermal management.

[0031] The field of human thermal management includes wearable smart clothing, medical protective equipment, and building and transportation applications.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] This invention discloses a method for preparing a POM / PVDF radiation-cooling composite membrane based on electrospinning. The method involves blending two polymers with good properties through physical stirring, followed by electrospinning to prepare a micro / nanofiber membrane. The resulting radiation-cooling membrane possesses excellent radiation cooling performance, good thermal stability, and mechanical strength. Furthermore, inorganic nanoparticles can be added to the polymer matrix to further optimize the overall cooling performance of the radiation-cooling membrane, demonstrating broad application prospects and practical market value.

[0034] This invention is a method for preparing radiation-cooling fiber membranes based on electrospinning technology. Electrospinning does not require sophisticated structural design or complex preparation techniques. Compared with other technologies, it has the advantages of low cost and large-area preparation. It is suitable for the preparation of polymer-based fiber materials and can be well compatible with various application scenarios.

[0035] This invention provides a POM / PVDF radiation-cooling composite membrane based on electrospinning. POM is used as a modifier to regulate the structure and performance of PVDF. Combined with electrospinning technology, a fiber membrane with a diameter close to the solar wavelength is prepared to enhance its scattering of solar wavelength and improve radiation-cooling performance. The resulting optimal radiation-cooling composite membrane can achieve a high emissivity of 90% in the 8-13μm range and a reflectivity of 87% in the 200-1400nm range, exhibiting good radiation-cooling potential.

[0036] The radiation-cooling composite membrane of the present invention has broad application potential in personal thermal management. By studying the preparation of radiation-cooling membranes using electrospinning, a better and lower-cost solution can be provided for this field, which has important research significance and market practical value. Attached Figure Description

[0037] Figure 1 The images shown are SEM images of four composite membranes with different proportions obtained in Examples 1-4; where (a) is the SEM image of the composite membrane prepared in Example 1; (b) is the SEM image of the composite membrane prepared in Example 2; (c) is the SEM image of the composite membrane prepared in Example 3; and (d) is the SEM image of the composite membrane prepared in Example 4.

[0038] Figure 2 The Fourier transform infrared (FT-IR) spectra of the four composite films with different proportions obtained in Examples 1-4 are shown below; where P100 is the FT-IR spectrum of the composite film prepared in Example 1; P91 is the FT-IR spectrum of the composite film prepared in Example 2; P73 is the FT-IR spectrum of the composite film prepared in Example 3; and P55 is the FT-IR spectrum of the composite film prepared in Example 4.

[0039] Figure 3The infrared emissivity curves are for four different ratios of radiation-cooled composite fiber membranes obtained in Examples 1-4; where P100 is the infrared emissivity curve of the composite membrane prepared in Example 1; P91 is the infrared emissivity curve of the composite membrane prepared in Example 2; P73 is the infrared emissivity curve of the composite membrane prepared in Example 3; and P55 is the infrared emissivity curve of the composite membrane prepared in Example 4.

[0040] Figure 4 The following are the reflectance curves of four composite films with different ratios obtained in Examples 1-4; where P100 is the reflectance curve of the composite film prepared in Example 1; P91 is the reflectance curve of the composite film prepared in Example 2; P73 is the reflectance curve of the composite film prepared in Example 3; and P55 is the reflectance curve of the composite film prepared in Example 4. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field. Test methods in the following embodiments that do not specify specific experimental conditions are generally performed under conventional experimental conditions. Unless otherwise specified, the reagents and raw materials used in the present invention are all commercially available.

[0042] The experimental steps described in this invention include: first, carefully rinsing the inner and outer walls of the beaker and the magnetic stir bar with deionized water; then placing the rinsed beaker and magnetic stir bar into a vacuum drying oven, setting the drying temperature to 50°C for 12 hours to remove moisture at low temperature; accurately weighing the required mass of PVDF and POM according to the solute content of 10wt%, and then accurately weighing the required mass of HFIP; covering the mouth of the beaker with plastic wrap to prevent solvent evaporation; first, slowly adding the PVDF powder to the HFIP solvent, simply covering the mouth of the beaker with plastic wrap and magnetically stirring; after the PVDF has initially dissolved, slowly adding the POM to the beaker and stirring at room temperature on a magnetic stirrer for no less than 6 hours to ensure that the components are fully dissolved, ideally until fully dissolved and uniformly stirred to a colorless and transparent state; allowing the solution to stand for 1-2 hours or more to ensure the system is uniform and stable (if conditions permit, an ultrasonic degassing step can be performed); finally, a series of characterization analyses are performed on the thin film material.

[0043] Example 1

[0044] This embodiment provides a method for preparing a POM / PVDF radiation-cooling composite film based on electrospinning, including the following steps:

[0045] S1. Before the experiment, calculate the amount of experimental raw materials required for each ratio. Weigh the experimental raw materials according to the calculated values ​​using an electronic balance and mix them into a solution in a certain ratio. The solvent is hexafluoroisopropanol (HFIP), the mass of polyvinylidene fluoride (PVDF) is 2.5g, and the mass of polyoxymethylene (POM) is 0g, while ensuring that the solute content is 10%. Add the PVDF and POM powders to the solvent in sequence, and place them on a magnetic stirrer to stir for a certain period of time to ensure that the solution is completely mixed. The speed is set to 500r / min.

[0046] S2. After stirring until initially uniformly distributed, let it stand for a short time (more than 2 hours) and then sonicate it for 5 minutes to remove air bubbles from the solution.

[0047] S3. Electrospin the obtained spinning solution and adjust the appropriate spinning parameters (spinning distance, feed speed, voltage, etc.) so that the droplets at the needle can stably form Taylor cones under the action of the electric field and stack at the receiving end to form a fiber membrane.

[0048] S4. After spinning is complete, remove the aluminum foil from the receiving end and place it at room temperature for more than 24 hours. Then place it in a vacuum drying oven and dry it at 60°C for 12 hours to remove residual solvent components. Then carefully peel off the membrane sample with tweezers, number it and save it.

[0049] Example 2

[0050] This embodiment provides a method for preparing a POM / PVDF radiation cooling composite film based on electrospinning. This embodiment is basically the same as that of Embodiment 1, except that in step S1, the mass of polyvinylidene fluoride (PVDF) is 1.75g ​​and the mass of polyoxymethylene (POM) is 0.75g, with a mass ratio of 9:1.

[0051] Example 3

[0052] This embodiment provides a method for preparing a POM / PVDF radiation cooling composite film based on electrospinning. This embodiment is basically the same as that of Embodiment 1, except that in step S1, the mass of polyvinylidene fluoride (PVDF) is 2.25g and the mass of polyoxymethylene (POM) is 0.25g, with a mass ratio of 7:3.

[0053] Example 4

[0054] This embodiment provides a method for preparing a POM / PVDF radiation cooling composite film based on electrospinning. This embodiment is basically the same as that of Embodiment 1, except that in step S1, the mass of polyvinylidene fluoride (PVDF) is 1.25g and the mass of polyoxymethylene (POM) is 1.25g, and the mass ratio of the two is 1:1.

[0055] Characterization analysis

[0056] The four types of radiation-cooling composite films prepared in Examples 1-4 were analyzed by SEM, and the results are as follows: Figure 1 As shown. Figure 1 The images show the scanning electron microstructures of P100, P91, P73, and P55 at a magnification of 4000x. Figure 1 (a) It can be seen that the pure PVDF film exhibits a large number of coarse granular crystalline aggregates with uneven overall distribution, and the fiber web structure has not yet been effectively formed. This indicates that without the participation of POM, the film-forming uniformity and spinning stability of PVDF are poor. This is related to its low crystallinity and flow properties, resulting in insufficient fiber nucleation and stretching during the spinning process. Figure 1 (b) At a 9:1 ratio, a distinct fiber network begins to form, with fibers interwoven and slightly coarse in diameter. Some particles remain attached to the fibers, but the overall distribution becomes more uniform. This indicates that the addition of a small amount of POM begins to play a nucleation role, helping to improve fiber morphology and enhancing rheological properties and electrospinning stability at the microscale. Figure 1 (c) With a 7:3 ratio, the fiber network structure is more developed, the fiber diameter is further reduced, the arrangement is more compact, and particle aggregation is reduced. This indicates that the increase of POM effectively promotes the fiber nucleation rate and the stretchability of the solution, significantly improving fiber continuity during electrospinning. The composite system exhibits good compatibility at this stage, which helps to form a complete, dense membrane structure with a porous network. Figure 1 (d) This sample, with a POM ratio further increased to 5:5, exhibits the most uniform fiber morphology, with fine and densely distributed fibers and virtually no visible particle adhesion, resulting in excellent overall network formation. This indicates that at this ratio, the interaction between POM and PVDF reaches its optimal state. POM significantly enhances the nucleation density, solution stability, and electrospinning tensile strength, achieving a high-quality nanofiber network construction. This structure not only helps improve the thermal stability and mechanical properties of the membrane but also provides greater freedom for optical scattering and infrared radiation paths, which is beneficial for improving radiation cooling effects. In summary, the SEM images clearly show that the P55 sample exhibits the optimal fiber structure morphology and has good application potential.

[0057] Fourier transform infrared spectroscopy analysis was performed on the four types of radiation-cooling composite films prepared in Examples 1-4, and the results are as follows: Figure 2 As shown. Figure 2 Fourier transform infrared spectra of four different ratios (P100, P91, P73, P55). Figure 2The study presents the FTIR spectral characteristics of four PVDF / POM composite film samples with different ratios in the 700–950 cm⁻¹ band. This region is crucial for identifying different PVDF crystal forms, primarily used to determine the relative presence of the α and β phases in the material. Based on the characteristic peaks of PVDF crystal forms, it can be determined that the peaks are approximately 763 cm⁻¹. -1 The peak at approximately 840–842 cm⁻¹ is a characteristic absorption peak of the α phase, while the peak at approximately 840–842 cm⁻¹ is a characteristic absorption peak of the α phase. -1 The peak at this point is a characteristic absorption peak of the β phase. As the POM doping ratio increases, the crystal structure of PVDF in the composite film gradually transforms from the α phase to the β phase. This structural evolution trend is more obvious in samples P73 and P55, manifested as an increase in the β phase absorption peak and a decrease in the α phase peak. This result confirms the effectiveness of POM in inducing crystallization and provides a theoretical basis and data support for further improving the infrared performance of the composite film and constructing efficient radiation cooling functional materials.

[0058] Infrared emissivity tests were performed on the four types of radiation-cooling composite films prepared in Examples 1-4, and the results are as follows: Figure 3 As shown. Figure 3 The infrared emissivity graphs for four samples were presented, primarily analyzing the emissivity of the four fiber membranes within the 2.5-15 μm range. The graphs show the infrared emissivity variations of four PVDF / POM composite membrane samples with different ratios (P100, P91, P73, and P55) in the 2-15 μm band, reflecting the material's thermal radiation performance in the mid-to-far infrared range, specifically in the radiative cooling core band, i.e., the atmospheric window of 8-13 μm. The graphs clearly show that different ratios affect the infrared emissivity. Within the 8-13 μm range, the emissivity curve of sample P73 is generally higher than the other three samples, exhibiting the best infrared radiation capability. P55's emissivity performance is slightly lower than P73's; both can reach a maximum emissivity of 90% in the 8-13 μm range.

[0059] The solar reflectivity of the four types of radiation-cooling composite films prepared in Examples 1-4 was tested, and the results are as follows: Figure 4 As shown. Figure 4 The reflectance curves of four different films were analyzed, and the reflectance of the materials in the 200-1400 nm range was used to reflect the reflectance of the radiative cooling material in the solar wavelength band. All four materials achieved a reflectance of over 80%, with the P55 fiber film exhibiting the best reflectance (highest curve), achieving an average reflectance of over 87% in the 400-1400 nm wavelength range. Therefore, the P55 composite fiber film possesses superior reflectance performance, while the P73 film's reflectance performance is slightly lower, but it still maintains an average reflectance of around 82% in the 400-1400 nm range.

[0060] Performance characterization tests showed that various composite membrane samples were successfully prepared by electrospinning POM and PVDF in HFIP solution systems with different mass ratios (10:0, 9:1, 7:3, 5:5). The morphology, structure, and radiation spectral properties of these samples were systematically analyzed using multiple characterization methods. Considering all aspects, the P55 composite membrane exhibits the best performance in terms of microstructure and spectral properties, making it the highest-performing passive radiation cooling material in this invention. It has promising application prospects and is suitable for personal thermal management applications. Future optimization of the fiber structure and processing, combined with evaporative cooling or phase change technologies, will enable its practical application and contribute to energy conservation and environmental control.

[0061] The above description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. The present invention is not limited to the above embodiments. Any obvious improvements, substitutions, or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the scope of protection of the present invention. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a POM / PVDF radiation-cooled composite membrane based on electrospinning, characterized in that, Includes the following steps: Step 1: Before the experiment begins, calculate the amount of experimental raw materials required for each ratio. Weigh the experimental raw materials using an electronic balance, which are the solvent HFIP and the solutes PVDF and POM powder. Step 2: Add PVDF powder to HFIP solvent and stir to fully dissolve the PVDF powder in the solution. Gradually add POM powder to the initially obtained PVDF solution and then stir on a magnetic stirrer to mix them completely and evenly. After stirring for a period of time, ultrasonically treat the spinning solution. Step 3: Electrospin the obtained spinning solution, adjust the appropriate spinning parameters so that the droplets at the needle can stably form Taylor cones under the action of electric field, and stack at the receiving end to form a fiber membrane. Step 4: After spinning is completed, the aluminum foil at the receiving end is removed, placed at room temperature for more than 24 hours, and then subjected to low-temperature drying treatment. Finally, the performance of the film material is characterized and analyzed.

2. The method for preparing a POM / PVDF radiation-cooling composite membrane based on electrospinning according to claim 1, characterized in that, In step 1, the total mass percentage of PVDF and POM is 5-15%, of which the mass percentage of POM in the solution is 0-5%.

3. The method for preparing a POM / PVDF radiation-cooled composite membrane based on electrospinning according to claim 2, characterized in that, The optimal total mass percentage of PVDF and POM is 10%.

4. The method for preparing a POM / PVDF radiation-cooling composite membrane based on electrospinning according to claim 2, characterized in that, The optimal concentration of POM in the solution is 5% by mass.

5. The method for preparing a POM / PVDF radiation-cooled composite membrane based on electrospinning according to claim 1, characterized in that, In step 2, the PVDF concentration is 5-10%, the magnetic stirrer speed is set to 500 r / min, and the stirring temperature is room temperature (25℃).

6. The method for preparing a POM / PVDF radiation-cooled composite membrane based on electrospinning according to claim 1, characterized in that, The parameters for electrospinning in step 3 are as follows: spinning needle size 18 to 22, spinning distance 80 to 200 mm, ambient temperature 25 ℃, voltage 8 to 15 kV, spinning speed 0.1 to 0.4 mm / min, and relative humidity 30% to 50%.

7. The method for preparing a POM / PVDF radiation-cooling composite membrane based on electrospinning according to claim 6, characterized in that, The spinning needle is No. 20, the spinning distance is 180 mm, the ambient temperature is 25 ℃, the voltage is 12 kV, the spinning speed is 0.2 mm / min, and the relative humidity is 40%.

8. The method for preparing a POM / PVDF radiation-cooled composite membrane based on electrospinning according to claim 1, characterized in that, The low-temperature drying process in step 4 involves drying in a vacuum drying oven at 60°C for 6 to 12 hours or more to remove residual solvent components.

9. A POM / PVDF radiation-cooling composite membrane based on electrospinning, characterized in that, Prepared by any one of the methods described in claims 1 to 8.

10. The application of the POM / PVDF radiation cooling composite membrane based on electrospinning as described in claim 9 in the field of human body thermal management.

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