Double-sided wearable flexible sensing device with dynamic thermal management capability and preparation method thereof

Abstract

The invention discloses a double-sided wearable flexible sensing device with dynamic thermal management capability and a preparation method of the double-sided wearable flexible sensing device, and belongs to the field of multi-response type flexible sensors. Comprising a thermoplastic polyurethane fiber membrane, sodium alginate / silk fibroin aerogel and a silk fibroin / graphene oxide fiber membrane. Thermoplastic polyurethane particles are dissolved in a mixed solution of tetrahydrofuran and N, N-dimethylformamide to prepare a spinning solution, and a TPU nanofiber membrane is prepared through an electrostatic spinning technology; the preparation method comprises the following steps: introducing double-dispersed magnetic particles MPs into a polymer solution of sodium alginate and silk fibroin, and preparing SA / SF aerogel through a freeze-drying technology; the preparation method comprises the following steps: introducing silk fibroin into a graphene oxide dispersion liquid, pouring a polyoxyethylene solution into a prepared SF / GO solution to obtain a spinning solution, preparing an SG nanofiber membrane by virtue of an electrostatic spinning technology, and performing hot pressing by virtue of a hot press to form a multi-layer composite sensing device.

Description

Technical Field

[0001] This invention belongs to the field of multi-response flexible sensors, specifically relating to a double-sided wearable flexible sensor device with dynamic thermal management capabilities and its fabrication method. Background Technology

[0002] Wearable sensors are playing an increasingly prominent role in human-computer interaction, especially in cutting-edge applications with stringent requirements for high sensitivity and rapid response. However, existing flexible sensor technologies still have significant limitations: on the one hand, they generally lack dynamic thermal management capabilities, making it difficult to maintain stable sensing performance in interactive tasks requiring real-time thermal regulation; on the other hand, the difficulty in accurately distinguishing different types of complex mechanical excitations (such as pressure, tension, and bending) restricts the accuracy and robustness of signal recognition. Furthermore, the structural rigidity of traditional sensor materials limits their close fit to the curved surfaces of the human body, affecting wearing comfort and application adaptability. Therefore, developing novel flexible sensors with active thermal management capabilities and the ability to effectively decouple complex mechanical signals has become a key path to overcome current technological bottlenecks.

[0003] To address the aforementioned issues, this invention proposes a sensing material based on a multilayer composite structure and freeze-drying technology. Through electrospinning of TPU and SG fiber membranes, and the introduction of magnetic microparticles during aerogel preparation, synergistic control of multiple physical responses, including force and heat, is achieved. This material not only possesses excellent flexibility and surface fit, adapting to complex morphologies with varying curvatures, but also exhibits superior electrical conductivity and thermal management properties, enabling its widespread application in diverse and complex human-computer interaction environments. Summary of the Invention

[0004] To address the aforementioned issues, this invention proposes a sensing material based on a multilayer composite structure and freeze-drying technology. Through electrospinning of TPU and SG fiber membranes, and the introduction of magnetic microparticles during aerogel preparation, synergistic control of multiple physical responses, including force and heat, is achieved. This material not only possesses excellent flexibility and surface fit, adapting to complex morphologies with varying curvatures, but also exhibits superior electrical conductivity and thermal management properties, enabling its widespread application in diverse and complex human-computer interaction environments.

[0005] The purpose of this invention is to provide a double-sided wearable flexible sensor device with dynamic thermal management capabilities, comprising a thermoplastic polyurethane nanofiber membrane, sodium alginate / silk fibroin aerogel, and a silk fibroin / graphene oxide fiber membrane arranged in a layered structure by thermopressing. The sodium alginate / silk fibroin aerogel contains bidispersed magnetic microparticles (MPs). The thermoplastic polyurethane nanofiber membrane is prepared by electrospinning from TPU spinning solution, and the silk fibroin / graphene oxide fiber membrane is prepared by electrospinning from GO / silk fibroin blend spinning solution.

[0006] Another objective of this invention is to provide a method for fabricating a double-sided wearable flexible sensor with dynamic thermal management capabilities. This method has a short manufacturing cycle, simple process, low cost, and is suitable for mass production. Furthermore, by changing the material of the fiber membrane on each side of the sensor, the performance of the sensor in terms of thermal management can be improved.

[0007] A method for fabricating a double-sided wearable flexible sensor device with dynamic thermal management capabilities includes the following steps: Step S1: Preparation of SA / SF aerogel Sodium alginate and silk fibroin were separately added to deionized water and stirred at a set temperature for a certain time until the solution was homogeneous and free of particles. The two were then mixed and stirred, and glycerol was added to generate a homogeneous polymer solution. Bidisperse magnetic microparticles (MPs) and calcium chloride solution were added sequentially to the polymer solution, and stirred until the magnetic microparticles were completely dissolved. A homogeneous composite solution was then obtained by ultrasonic vibration. The composite solution was then poured into a self-made glass membrane container and transferred to a pre-frozen freeze dryer. After freezing under a uniform magnetic field for 6 hours, a vacuum pump was turned on for drying. Finally, a dry, porous magnetic SA / SF aerogel was obtained.

[0008] Step S2: Preparation of TPU nanofiber membrane A certain proportion of tetrahydrofuran is mixed with N,N-dimethylformamide, and then TPU particles are added to the mixed solution. The mixture is stirred until completely dissolved to obtain an electrospinning solution. Finally, the electrospinning solution is sprayed onto a collector through a syringe to form a TPU fiber membrane.

[0009] Step S3: Preparation of silk fibroin / graphene oxide (SG) fiber membrane Silk fibroin was added to a certain proportion of GO dispersion, and then a certain proportion of polyethylene oxide solution was prepared and poured into the prepared SF / GO solution. The mixture was stirred until complete to obtain the spinning solution. Finally, the electrospinning solution was sprayed onto the collector through a syringe to form an SG nanofiber membrane.

[0010] Step S4: Hot pressing TPU fiber membrane and SG nanofiber membrane were placed on both sides of the porous aerogel and hot-pressed at a certain temperature using a hot press.

[0011] This invention patent also includes the following structural features: In the preparation method described above, in step S1: sodium alginate (Mw=10-15kDa), silk fibroin (average Mw~250,000), the mass ratio of sodium alginate to silk fibroin is in the range of 1:1-4. Through comparative experiments on the content of added glycerol, the aerogel prepared with glycerol content of 2wt% has the best flexibility.

[0012] As described above, the bidispersed magnetic microparticles of this invention possess a typical double-layer core-shell structure, with multi-walled carbon nanotubes coating the surface of the gelatin-coated magnetic microparticles, thereby constructing a highly efficient conductive network for the sensor. Specifically, the preparation method of the magnetic microparticles is as follows: R1. A certain amount of carbonyl iron powder, magnetic Fe3O4 particles, and sodium chloride are weighed, mixed, and added to a gelatin aqueous solution. The mixture is then subjected to ultrasonic oscillation to ensure the gelatin evenly coats the carbonyl iron powder and Fe3O4 powder surfaces. The coated magnetic particles are then separated using a permanent magnet, washed with deionized water, and dried. The mass-volume concentration of the gelatin aqueous solution is 0.1 g / mL. The mass ratio of carbonyl iron powder, magnetic Fe3O4, and sodium chloride is 4:0.5:0.2. The mass ratio of carbonyl iron powder to gelatin in the gelatin aqueous solution is 4:2.5. The average particle size of the carbonyl iron powder is 3.5 μm, and its density is 7.9 g / cm³. The average particle size of the magnetic Fe3O4 is 20 nm. R2. At a temperature of 55℃~65℃, multi-walled carbon nanotubes were added to a mixed acid prepared by mixing nitric acid and sulfuric acid in a molar ratio of 3:1, and the mixture was irradiated with ultrasound for 12 hours to obtain an acidified multi-walled carbon nanotube solution. R3. Add the gelatin-coated magnetic microparticles obtained in step R1 to the acidified multi-walled carbon nanotube solution prepared in step R2 and perform ultrasonic oscillation to coat the surface of the gelatin-coated magnetic microparticles with multi-walled carbon nanotubes. Then, separate the multi-walled carbon nanotube-coated magnetic microparticles with a permanent magnet, and wash and dry them with deionized water to obtain the final product.

[0013] In the sensor fabrication method described above, in step S1, the stirring speed is 350 r / min to 450 r / min, the stirring time is 20 min to 30 min, and the stirring temperature is 55℃ to 65℃.

[0014] In the sensor preparation method described above, in step S1, the concentration of calcium chloride solution is 0.9~1.2wt%, the amount added is 10~15wt%, and the concentration after adding MPs is 0.025~0.034g / ml.

[0015] In the sensor fabrication method described above, in step S1, the vacuum degree during freeze drying is below 10 Pa.

[0016] In the sensor preparation method described above, in step S2, the ratio of tetrahydrofuran to N,N-dimethylformamide is in the range of 1:1~2; TPU particles are added to prepare a TPU solution of 14-19 wt%, preferably a TPU solution of 17-19 wt%.

[0017] In the sensor fabrication method described above, in step S2, the distance between the syringe and the collector is 5cm to 25cm; the voltage range is 10kV to 25kV; the propulsion speed is 0.5 to 3ml / h; and the spinning time is 2 to 6h.

[0018] In the sensor preparation method described above, in step S3, the volume ratio of polyethylene oxide solution to GO dispersion is 1:1~2, the concentration of GO dispersion is 2 mg / ml, and the amount of silk fibroin added is 6~8 wt% of GO dispersion.

[0019] In the sensor fabrication method described above, in step S3, the distance between the syringe and the collector is 5cm to 20cm; the voltage range is 10kV to 20kV; the propulsion speed is 0.1 to 2ml / h; and the spinning time is 8 to 16h.

[0020] In the sensor fabrication method described above, in step S4, the hot-pressing temperature is 50℃-100℃ and the hot-pressing time is 3min-10min.

[0021] Due to the adoption of the above technical solution, the technical effects achieved by the present invention are as follows: This invention uses natural polymer sodium alginate and silk fibroin, which have good biocompatibility and biosafety, making them suitable for application in electronic skin and wearable devices.

[0022] In the material selected in this invention, the -COOH groups on the SA molecules and the -NH groups on the SF molecules undergo a bio-crosslinking reaction through hydrogen bonds, forming an intertwined first-layer crosslinking network. The SA molecules then react with Ca... 2+ Ions undergo chelation reactions to produce a second cross-linked network with an "eggshell" structure. These two networks are generated independently, interpenetrate and entangle with each other, and establish a stable three-dimensional skeletal structure.

[0023] The bidispersed polymers selected in this invention are uniformly adsorbed onto the three-dimensional porous framework of the polymer through magnetic field and electrostatic action, forming a continuous conductive network, making SA / SF aerogel a good conductive material.

[0024] The SA / SF aerogel obtained by this invention has good pore structure, tensile strength and sensing performance, and its thermal insulation performance is significantly better than that of cotton, linen and other materials.

[0025] The TPU nanofiber membrane of this invention is produced by electrospinning and has high infrared reflectivity, which provides excellent heat insulation performance for the sensor, thereby improving the sensor's heat insulation and cooling capability in hot environments.

[0026] The SG fiber membrane produced by this invention is produced using an electrospinning process. The SG nanofiber membrane has a good solar energy absorption rate and can effectively absorb infrared energy from external radiation and convert it into heat energy, enabling the sensor sample to obtain a good photothermal conversion capability, providing continuous warmth to the human body in cold environments and significantly improving the comfort of the body.

[0027] The multifunctional sensor fabricated in this invention exhibits excellent mechanical response sensitivity, and the prepared nanofiber membrane possesses excellent air permeability, making it suitable for contact with human skin. Furthermore, this sensor distinguishes between external tensile and bending excitations by generating different positive and negative signals, demonstrating a crucial ability to clearly differentiate excitations. The sensor also exhibits good thermal insulation and cooling performance, as well as photothermal conversion capabilities.

[0028] The flexible sensor device fabricated in this application has a three-layer composite structure: a sandwich-like composite architecture with mechanical gradient and functional asymmetry is constructed by hot-pressing a TPU fiber membrane and an SG nanofiber membrane onto both sides of a porous SA / SF aerogel. This structure not only enhances the overall flexibility and fit but also provides a material basis for double-sided thermal management.

[0029] The flexible sensor device prepared in this application has a dual-sided dynamic thermal management mechanism: by utilizing the differences in infrared absorptivity, solar reflectivity, and photothermal conversion between the two fiber membranes, the temperature of the contact interface can be regulated. The TPU film focuses on radiative cooling, the SG film focuses on absorbing sunlight and converting it into heat energy, and the aerogel structure focuses on thermal insulation. The three work together to maintain thermal comfort in complex wearable environments.

[0030] The flexible sensor fabricated in this application is based on a method for distinguishing between positive and negative electrical signals: combining magnetic microparticle doping with the piezoresistive properties of aerogel, the sensor can output electrical signals with different polarities according to the stress type (tension, bending). By analyzing the positive and negative responses corresponding to different mechanical excitations, accurate identification and classification of complex deformation modes can be achieved, effectively overcoming the recognition ambiguity problem of traditional flexible sensors under multiple excitations.

[0031] This application presents a multi-response flexible sensor with excellent sensitivity, flexibility, and stability. The sensor can distinguish between external tensile and bending excitations by generating different positive and negative signals, demonstrating a crucial ability to clearly differentiate excitations. Furthermore, this multi-response flexible sensor has broad application potential in thermal management. The TPU fiber membrane side possesses radiative cooling capabilities, while the SG fiber membrane side exhibits excellent solar energy absorption and photothermal conversion capabilities, enabling the sensor to flexibly adapt to different temperature environments, from high-temperature heat dissipation to low-temperature heating. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the multi-response flexible sensor device obtained in Embodiment 1 of the present invention; Figure 2 This is a flowchart illustrating the fabrication process of the multi-response flexible sensor device obtained in Embodiment 1 of the present invention. Figure 3 This is a cross-sectional scanning electron microscope (SEM) image of the aerogel in the multi-response flexible sensor device prepared in Example 1 of the present invention. Figure 4 This is a scanning electron microscope (SEM) image of the TPU nanofiber membrane structure prepared in Example 1 of the present invention; Figure 5 This is a scanning electron microscope (SEM) image of the SG nanofiber membrane structure obtained in Example 1 of the present invention; Figure 6 The curves showing the change in tensile mechanical properties of the multi-response flexible sensor device obtained in Embodiment 1 of the present invention are shown. Figure 7 The curves showing the change in electrical response performance of the multi-response flexible sensor device prepared in Embodiment 1 of the present invention under different tensile strains are shown. Figure 8 The curves showing the change in electrical response performance of the multi-response flexible sensor device prepared in Embodiment 1 of the present invention under different bending strains are shown. Figure 9 The working life curve of the multi-response flexible sensor device prepared in Embodiment 1 of the present invention under a certain tensile strain is shown. Figure 10 This is a diagram showing the thermal insulation performance of the intermediate aerogel portion of the multi-response flexible sensor device prepared in Embodiment 1 of the present invention. Figure 11 The infrared reflectance curves of the TPU fiber membrane and SG fiber membrane structures prepared in Example 1 of the present invention at different wavelengths are shown. Figure 12 The emission curve of the TPU fiber membrane prepared in Example 1 of this invention is shown in the mid-infrared emission window. Figure 13The infrared transmittance curves of the SG fiber membrane structure obtained in Example 1 of this invention at different wavelengths are shown. Figure 14 The solar energy absorption curves of the SG fiber membrane structure obtained in Example 1 of this invention at different wavelengths are shown. Among them, 1. thermoplastic polyurethane nanofiber membrane, 2. sodium alginate / silk fibroin aerogel, and 3. silk fibroin / graphene oxide fiber membrane. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0034] As attached Figure 1 As shown, a double-sided wearable flexible sensor (device) with dynamic thermal management capability has a layered structure, including a thermoplastic polyurethane nanofiber membrane 1, sodium alginate / silk fibroin aerogel 2, and silk fibroin / graphene oxide fiber membrane 3, which are arranged in a layered structure by hot pressing.

[0035] Example 1 A method for fabricating a bifacial wearable flexible sensor device with dynamic thermal management capabilities, such as... Figure 2 As shown, it includes the following steps: Preparation of S1 and SA / SF aerogels: 0.75g sodium alginate and 0.5g silk fibroin were added separately to 25ml of deionized water (sodium alginate weight-average molecular weight Mw = 10-15kDa, silk fibroin weight-average molecular weight Mw ~ 250,000). The mixture was stirred at 55℃ for a certain time until the solution was homogeneous and free of particles. The two were then mixed and stirred, and 2wt% glycerol was added to generate a homogeneous polymer solution. Bidisperse magnetic microparticles (MPs) and calcium chloride solution (1wt% concentration, 10mL) were added to the polymer solution, and 2g of bidisperse magnetic microparticles (MPs) were added. The mixture was stirred until the magnetic microparticles were completely dissolved in the polymer solution. A homogeneous composite solution was then obtained by ultrasonic vibration. The composite solution was then poured into a self-made glass membrane container and transferred to a pre-frozen freeze dryer. After freezing for 6 hours under a uniform magnetic field, the vacuum pump was turned on for drying. Finally, a dry, porous magnetic SA / SF aerogel was obtained.

[0036] S2. Preparation of TPU nanofiber membrane: Mix 10 ml of N,N-dimethylformamide and 10 ml of tetrahydrofuran, then add 3.4 g of TPU particles to the mixed solution, and stir at 65°C for 1 hour until completely dissolved. Let stand for half an hour and then collect the solution with a syringe. Finally, spray the electrospinning solution onto the collector through the syringe to form a fiber membrane.

[0037] S3, SG nanofiber membrane preparation: 1.5g of silk fibroin SF was added to 20ml of GO dispersion and deionized water mixture, and then 1.25g of polyethylene oxide (PEO) powder was added to 25ml of deionized water and stirred evenly. Then, it was poured into the prepared SF / GO solution and stirred completely to obtain the spinning solution. Finally, the electrospinning solution was sprayed onto the collector through a syringe to form an SG nanofiber membrane.

[0038] S4. Place the TPU fiber membrane and SG nanofiber membrane on both sides of the aerogel and hot press them at 60°C for 5 minutes to form the aerogel.

[0039] Example 2 The preparation method of the double-sided wearable flexible sensor with dynamic thermal management capability in this embodiment is basically the same as the preparation process in Example 1, except that in step (1), 2.5wt% glycerol is added to generate a uniform polymer solution.

[0040] Example 3 The preparation method of the double-sided wearable flexible sensor with dynamic thermal management capability in this embodiment is basically the same as the preparation process in Embodiment 1, except that in step (1), 0.75g of silk fibroin is added to 25ml of deionized water.

[0041] Example 4 The preparation method of the double-sided wearable flexible sensor with dynamic thermal management capability in this embodiment is basically the same as the preparation process in Embodiment 1, except that in step (1), 1g of sodium alginate is added to 25ml of deionized water.

[0042] Example 5 The preparation method of the double-sided wearable flexible sensor with dynamic thermal management capability in this embodiment is basically the same as the preparation process in Embodiment 1, except that in step (2), 3g of TPU particles are added to the mixed solution.

[0043] Example 6 The preparation method of the double-sided wearable flexible sensor with dynamic thermal management capability in this embodiment is basically the same as the preparation process in Example 1, except that: in step (3), 10 ml of GO aqueous dispersion is added.

[0044]

[0045] Experimental Example The scanning electron microscope (SEM) image of the cross-section of the SA / SF aerogel obtained in Example 1 is shown below. Figure 3 As shown, scanning electron microscope (SEM) images of the TPU nanofiber membrane structure and the SG nanofiber membrane prepared in Example 1 are as follows. Figure 4 , 5 As shown. By Figure 3 It can be seen that the cross-section of the SA / SF aerogel has pores, indicating that the modified bidisperse magnetic particles are uniformly dispersed on the pore walls.

[0046] The flexible sensor device prepared in Example 1 was subjected to tensile mechanical property testing, and the results are as follows: Figure 6 As shown. By Figure 6 It can be seen that the maximum tensile strength of the sample at fracture can reach 44.3%, which shows good ductility and toughness.

[0047] The electrical response performance of the sensor device prepared in Example 1 was tested under different tensile strain excitations. The measured resistance change rate-tensile strength curves are shown below. Figure 7 As shown. Analysis of the sensor's sensitivity coefficient under strain revealed that the GF under tensile strain is 5.06. The deformation of adjacent conductive nanofibers under tensile load reduces the contact area in the conductive network, increases the distance between magnetic particles, and generates microcracks in the nanofibers, ultimately resulting in high sensitivity.

[0048] The electrical response performance of the sensor device prepared in Example 1 was tested under different bending conditions. The measured resistance change rate-bending curve is shown below. Figure 8 As shown. By Figure 8 It can be seen that by analyzing the sensitivity coefficient of the sensor under different bending strains, the GF is -1.02 under 0-25% bending strain and can reach -2.96 under 25-50% bending strain. When the bending strain increases, the aerogel layer is compressed, which significantly increases the conductive path formed inside it and the resistance decreases rapidly, thus producing higher sensitivity.

[0049] Depend on Figure 7 , Figure 8 It can be seen that during tensile action, the deformation of adjacent conductive nanofibers under tensile load reduces the contact area in the conductive network, while increasing the distance between magnetic particles. Therefore... Figure 7 The resistance exhibits an increasing change; during bending, the conductive path of the sensor decreases, increasing the contact area of ​​the conductive network and reducing the distance between magnetic particles, thus causing the resistance to decrease. Figure 8 It exhibits negative changes.

[0050] The sensor device prepared in Example 1 was subjected to a service life test under a 30° bending strain. The measured service life curve is shown below. Figure 9 As shown, it underwent more than 12,000 tensile cycles under a certain tensile strain, and the generated electrical signal remained stable, demonstrating good stability and reliability.

[0051] The thermal conductivity of the SA / SF aerogel prepared in Example 1 was tested, and the measured thermal conductivity is shown in the figure below. Figure 10 As shown. By Figure 10 It can be seen that the thermal conductivity of the aerogel is 0.064 W / m. -1 k -1 Although its thermal conductivity is higher than that of air, it is lower than that of cotton fabric (0.073 W / m²). -1 k -1 The sensor, along with commonly available substrate materials, provides excellent thermal insulation, which helps maintain body temperature in cold environments.

[0052] The infrared reflectance performance of the TPU nanofiber membrane and SG nanofiber membrane prepared in Example 1 was tested under different wavelength environments. Figure 11 As shown, the TPU nanofiber membrane has an infrared reflectance of 82% in the wavelength range of 300 to 2500 nm, while the SG nanofiber membrane has an infrared reflectance of 9% in the same wavelength range. Figure 12 As shown, the TPU nanofiber membrane has a mid-infrared emissivity of 91% in the 8-13 μm wavelength range.

[0053] The sensor device prepared in Example 1 was subjected to a solar energy absorption rate performance test on its SG side under simulated sunlight. For example... Figure 13 As shown, the transmittance of the SG fiber membrane is 3% in the wavelength range of 300 to 2500 nm. Figure 14 As shown, the solar energy absorption rate of the SG fiber membrane is 88% in the wavelength range of 300 to 2500 nm. In addition, the graphene sheets in the SG nanofiber membrane can effectively absorb infrared energy from external radiation, convert the absorbed infrared energy into heat energy, and further heat up through reflection from the material surface, thus enabling the sensor to have good photothermal conversion function.

[0054] The TPU nanofiber membranes and SG nanofiber membranes on both sides of the sensor in this application can achieve cooling and heating functions.

[0055] The TPU nanofiber membrane exhibits an infrared reflectance of up to 82% in the 300–2500 nm wavelength range and a mid-infrared emissivity of 91% in the 8–13 μm wavelength range, demonstrating its excellent infrared reflectivity. In practical wearable applications, when the TPU side of the sensor faces outward, this membrane effectively reflects infrared energy radiated from the environment and the human body, reducing heat transfer and thus providing passive cooling in high-temperature or light-exposed environments, maintaining a relatively stable interface temperature.

[0056] The SG nanofiber membrane exhibits an 88% solar energy absorption rate in the 300–2500 nm wavelength range, while its reflectivity in the infrared band is only 9%, demonstrating strong broadband heat absorption and photothermal conversion capabilities. The graphene oxide sheets in this membrane efficiently absorb sunlight and other infrared radiation, converting it into heat energy for rapid heating. When the SG side of the sensor faces outwards, it can raise the interface temperature in low-temperature environments, achieving a heating effect.

Claims

1. A dual-sided wearable flexible sensor device with dynamic thermal management capability, characterized by: The application relates to a laminated structure including a thermoplastic polyurethane nanofiber membrane (1), a sodium alginate / silk fibroin aerogel (2) and a silk fibroin / oxidized graphene fiber membrane (3) in sequence, wherein the sodium alginate / silk fibroin aerogel contains bimodal magnetic particles MP, the thermoplastic polyurethane nanofiber membrane is prepared by electrospinning of a TPU spinning solution, and the silk fibroin / oxidized graphene fiber membrane is prepared by electrospinning of a GO / silk fibroin blending spinning solution.

2. A method for fabricating a bifacial wearable flexible sensor device with dynamic thermal management capabilities, characterized in that... The application relates to a laminated structure including a thermoplastic polyurethane nanofiber membrane (1), a sodium alginate / silk fibroin aerogel (2) and a silk fibroin / oxidized graphene fiber membrane (3) in sequence, wherein the sodium alginate / silk fibroin aerogel contains bimodal magnetic particles MP, the thermoplastic polyurethane nanofiber membrane is prepared by electrospinning of a TPU spinning solution, and the silk fibroin / oxidized graphene fiber membrane is prepared by electrospinning of a GO / silk fibroin blending spinning solution. S1, preparation of the sodium alginate / silk fibroin aerogel (2): sodium alginate and silk fibroin are dissolved in water respectively, mixed and glycerol is added to obtain a polymer solution; bimodal magnetic particles MP and a calcium chloride solution are sequentially added to the polymer solution for dissolution, and a composite solution is obtained by ultrasonic treatment; the composite solution is poured into a mold and freeze-dried under the action of a uniform magnetic field to obtain a magnetic SA / SF aerogel; S2, preparation of the thermoplastic polyurethane nanofiber membrane (1): tetrahydrofuran and N,N-dimethylformamide are mixed, TPU particles are added for dissolution, and a TPU fiber membrane is obtained by electrospinning; S3, preparation of the silk fibroin / oxidized graphene fiber membrane (3): silk fibroin is added to a GO dispersion solution, and a polyethylene oxide solution is added for stirring to obtain an SG nanofiber membrane by electrospinning; S4, hot pressing: the TPU fiber membrane and the SG nanofiber membrane are placed on both sides of the sodium alginate / silk fibroin aerogel, and hot pressing is performed by using a hot press.

3. The method of claim 2, wherein the method further comprises: In step S1, the weight average molecular weight Mw of the sodium alginate is 10-15 kDa, the average weight average molecular weight Mw of the silk fibroin is 250,000, the mass ratio of the sodium alginate to the silk fibroin ranges from 1:1 to 4, and the addition amount of glycerol is 2 wt% of the total mass of the polymer.

4. The method of claim 2, wherein the method further comprises: In step S1, the bimodal magnetic particles MP and the calcium chloride are added for stirring and dissolution at a stirring speed of 350 r / min-450 r / min, a stirring time of 20 min-30 min and a stirring temperature of 55 DEG C-65 DEG C, and the vacuum degree during freeze-drying is below 10 Pa.

5. The method of claim 4, wherein the method further comprises: In step S1, the concentration of the calcium chloride solution is 0.9-1.2 wt%, the addition amount is 10-15 wt%, and the concentration after the addition of the MP is 0.025-0.034 g / ml.

6. The method of claim 2, wherein the method further comprises: In step S2, the volume ratio of the tetrahydrofuran to the N,N-dimethylformamide ranges from 1:1 to 2, and the TPU particles are added to prepare a TPU solution with a concentration of 14-19 wt%.

7. The method of claim 2, wherein the method further comprises: In step S3, the concentration of the polyethylene oxide solution is 4-6%, the volume ratio of the polyethylene oxide solution to the GO dispersion solution is 1:1-2, the concentration of the GO dispersion solution is 2 mg / ml, and the addition amount of the silk fibroin is 6-8 wt% of the GO dispersion solution.

8. The method of claim 2, wherein the method further comprises: In step S2, the distance between the syringe and the collector during electrospinning is 5cm-25cm; the voltage range is 10kV-25kV; the advancing speed is 0.5-3ml / h; and the spinning time is 2-6h; in step S3, the distance between the syringe and the collector during electrospinning is 5cm-20cm; the voltage range is 10kV-20kV; the advancing speed is 0.1-2ml / h; and the spinning time is 8-16h.

9. The method of claim 2, wherein the method further comprises: In step S4, the hot-pressing temperature is 40-80℃, and the hot-pressing time is 3-10min.

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