Composite fiber membrane, electromagnetic wave sensing and shielding driver and application thereof

Abstract

The invention relates to a composite fiber membrane, an electromagnetic wave sensing and shielding driver and application thereof, and provides a fiber-based composite membrane which has photo-thermal and moisture stimulation deformation and electromagnetic wave sensing and shielding functions. The composite fiber membrane has the advantages of light weight, flexibility, high machinability and the like, and has wide application prospects in the fields of electromagnetic wave shielding, electromagnetic wave sensing, flexible electronic equipment, intelligent wearable equipment, soft robots and the like.

Description

Technical Field

[0001] The present invention belongs to the field of functional materials, and in particular relates to a composite fiber membrane, an electromagnetic wave sensing and shielding driver and applications thereof. Background Art

[0002] In order to meet the electromagnetic protection needs of different scenarios, lightweight and efficient flexible electromagnetic wave shielding materials have become an important research direction in the current field of materials science. Fiber materials have the advantages of light weight, flexibility, continuous structure, and strong processability. They can be easily integrated with multiple functions through structural design and functional modification, and are expected to develop multifunctional electromagnetic protection materials.

[0003] Existing electromagnetic wave shielding materials usually only have passive electromagnetic shielding capabilities. Their single function limits the wide application of the materials, and it is especially difficult to meet the application needs of various smart devices and flexible electronic devices. The rapid development of flexible electronic devices, smart wearable devices and deformable structural equipment has put forward higher requirements for flexible electromagnetic shielding materials. Ideal electromagnetic wave shielding materials not only need efficient electromagnetic shielding performance, but also should have the ability to actively sense the intensity of electromagnetic waves, and even be able to trigger their own deformation through changes in the external environment (light, heat or humidity), and dynamically adjust their electromagnetic shielding performance, thereby achieving intelligent and dynamic electromagnetic shielding effects. This type of intelligent electromagnetic shielding material has great application prospects in the fields of intelligent protection, flexible electronics, military stealth, aerospace, etc.

[0004] In summary, the development of a type of fiber-based composite material that has both electromagnetic wave sensing / shielding and environmental response active deformation capabilities has important scientific significance and application value. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a composite fiber membrane, an electromagnetic wave sensing and shielding driver and their applications. The present invention realizes deformation response under light, heat and moisture stimulation through multi-layer structure design and functional modification, and has efficient electromagnetic wave sensing and shielding performance, providing new ideas and technical support for the development of environment-machine-human interaction.

[0006] The present invention provides a composite fiber membrane, which comprises a photothermal response layer, a conductive layer and a humidity response layer in sequence, wherein the photothermal response layer is a hydrophobic polymer fiber membrane containing photothermal filler; and the humidity response layer is a hydrophilic polymer fiber membrane containing hygroscopic filler.

[0007] The composite fiber membrane comprises, from top to bottom, a photothermal response layer, a conductive layer, and a humidity response layer.

[0008] The composite fiber membrane is a "sandwich" structure.

[0009] The conductive layer is a conductive film.

[0010] The composite fiber membrane is a fiber-based composite membrane that can be deformed by light, heat and moisture stimulation and has electromagnetic wave sensing and shielding functions.

[0011] Preferably, the thickness ratio of the photothermal response layer, the conductive layer and the humidity response layer is 10:1:1-1:1:10, and further the thickness ratio is 4:1:2-2:1:4.

[0012] Preferably, the total thickness of the composite fiber membrane is 20 μm-300 μm, and more preferably, the total thickness of the composite fiber membrane is 50 μm-150 μm.

[0013] The hydrophobic polymer fiber membrane in the photothermal response layer is loaded with photothermal filler; wherein the loading method includes one or more of embedding, surface modification, partial distribution, and dense arrangement.

[0014] The hydrophilic polymer fiber membrane in the humidity responsive layer is loaded with hygroscopic filler, wherein the loading method includes one or more of embedding, surface modification, partial distribution, and dense arrangement.

[0015] Preferably, the photothermal filler includes one or more of carbon black, graphite, black phosphorus, carbon nanotubes, graphene, graphene oxide, transition metal carbide MXene, polydopamine, a first metal nanomaterial, and a first metal oxide nanomaterial. The first metal nanomaterial is a first metal nanoparticle, nanowire or nanosheet, and the first metal oxide nanomaterial is a first metal oxide nanoparticle, nanowire or nanosheet.

[0016] Preferably, the first metal nanomaterial includes one or more of gold, silver, copper, platinum and palladium nanomaterials.

[0017] Preferably, the first metal oxide nanomaterial includes one or more of manganese dioxide, titanium dioxide, zinc oxide, indium tin oxide, cerium dioxide, ferroferric oxide, and hydrophilically modified ferroferric oxide nanomaterials.

[0018] Further preferably, the photothermal filler is a hydrophilically modified ferroferric oxide nanomaterial. Compared with other photothermal fillers, the hydrophilically modified ferroferric oxide not only ensures the rapid deformation and large deformation of the driver under infrared irradiation, but also interacts with the conductive layer, which helps to play a role in hysteresis loss of electromagnetic waves during the electromagnetic shielding process.

[0019] Preferably, the hygroscopic filler comprises one or more of silicon dioxide, zeolite, transition metal carbide MXene, graphene, graphene oxide, metal organic framework MOFs, covalent organic framework COFs, polydopamine, a second metal nanomaterial, and a second metal oxide nanomaterial. The second metal nanomaterial is a second metal nanoparticle, nanowire or nanosheet, and the second metal oxide nanomaterial is a second metal oxide nanoparticle, nanowire or nanosheet.

[0020] Preferably, the second metal nanomaterial includes one or more of hydrophilically modified silver, hydrophilically modified copper, hydrophilically modified gold, hydrophilically modified titanium, and hydrophilically modified nickel nanomaterials.

[0021] Preferably, the second metal oxide nanomaterial includes one or more of aluminum oxide, titanium dioxide, manganese dioxide, zinc oxide, and hydrophilically modified ferrosoferric oxide nanomaterial.

[0022] Further preferably, the hygroscopic filler is a hydrophilically modified ferroferric oxide nanomaterial. Compared with other hygroscopic fillers, the hydrophilically modified ferroferric oxide not only ensures the rapid and large deformation of the driver when stimulated by moisture, but also interacts with the conductive layer, and helps to reduce the hysteresis loss of electromagnetic waves during the electromagnetic shielding process.

[0023] The hydrophilic modified ferrosoferric oxide nanomaterials mentioned in the photothermal filler and the hygroscopic filler include but are not limited to those prepared by methods such as hydrothermal synthesis, or directly selecting commercially available products.

[0024] For example, the hydrothermal synthesis method is used to prepare hydrophilic modified ferroferric oxide nanomaterials, including: mixing ferric salt, ferrous salt and water, heating in a water bath, then adding sodium hydroxide solution, stirring and reacting at 80° C. for 20-30 minutes, and purifying to obtain.

[0025] Preferably, the hydrophobic polymer fiber membrane comprises one or more hydrophobic thermal expansion type polymer fiber membranes, wherein the thermal expansion coefficient of the hydrophobic thermal expansion type polymer is greater than 0 K. -1 ;

[0026] The hydrophobic heat-expandable polymer includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyester, polyurethane, polylactic acid, styrene-isoprene, and ethylene-vinyl acetate.

[0027] Furthermore, the hydrophobic polymer fiber membrane is a polyvinylidene fluoride fiber membrane. Polyvinylidene fluoride not only has good hydrophobicity, but is also a polymer with a high thermal expansion coefficient. When irradiated by infrared, the polymer matrix will expand, promoting the deformation of the actuator.

[0028] Preferably, the hydrophilic polymer fiber membrane comprises one or more hydrophilic heat shrinkable (negative expansion) polymer fiber membranes, wherein the thermal expansion coefficient is <0 K -1 .

[0029] The hydrophilic heat shrinkable polymer includes a fiber membrane of one or more of polyvinyl alcohol, polyacrylic acid, polyethylene glycol, polyvinyl pyrrolidone, polyethylene oxide, and polyacrylonitrile.

[0030] Further preferably, the hydrophilic polymer is polyvinyl pyrrolidone, which not only has good hydrophilicity but is also a polymer with a low (negative) thermal expansion coefficient. When irradiated by infrared, the polymer matrix will shrink, thereby promoting deformation of the actuator.

[0031] Preferably, the mass ratio of the photothermal filler to the hydrophobic polymer in the photothermal response layer is 10:1-1:1000, and more preferably, the mass ratio of the photothermal filler to the hydrophobic polymer is 1:20-1:5.

[0032] Preferably, the mass ratio of the hygroscopic filler to the hydrophilic polymer in the humidity responsive layer is 10:1-1:1000, and more preferably, the mass ratio of the hygroscopic filler to the hydrophilic polymer is 1:20-1:5.

[0033] Preferably, the electrical conductivity of the conductive layer is greater than 1000 S / m.

[0034] The conductive layer is a conductive material film.

[0035] Preferably, the conductive layer material is one or more of zero-dimensional material, one-dimensional material, and two-dimensional material; wherein the zero-dimensional material includes metal nanoparticles; the one-dimensional material includes metal nanowires; the two-dimensional material includes one or more of metal nanosheets and non-metallic nanosheets;

[0036] The metal nanoparticles include one or more of gold nanoparticles, platinum nanoparticles, silver nanoparticles, and copper nanoparticles; the metal nanowires include one or more of gold nanowires, platinum nanowires, silver nanowires, and copper nanowires;

[0037] The metal nanosheets include one or more of gold nanosheets, platinum nanosheets, silver nanosheets, and copper nanosheets;

[0038] The non-metallic nanosheets include one or more of transition metal carbide MXene, graphene, graphene oxide, molybdenum disulfide, tungsten disulfide, black scale, and metal organic framework (MOF) derivatives.

[0039] Further preferably, the conductive layer material is a two-dimensional sheet structure material, such as a transition metal carbide MXene film. The middle conductive layer plays a decisive role in the driver's ability to sense and shield electromagnetic waves. The high conductivity of two-dimensional sheet structure materials such as transition metal carbide MXene enables it to generate an induced electrostatic potential in the electromagnetic field to attract and repel free electrons inside it, thereby obtaining high sensitivity to sense electromagnetic waves. In addition, transition metal carbide MXene is a typical two-dimensional sheet material, and the film obtained by filtration has a layered stacking structure, which is conducive to the back and forth reflection of electromagnetic waves between layers, and plays a role in efficiently dissipating electromagnetic waves. In addition, the middle conductive layer also has positive significance for the photothermal drive and humidity drive of the driver. Two-dimensional sheet structure materials such as transition metal carbide MXene are hydrophilic. During the photothermal drive process of the driver, the transition metal carbide MXene film loses moisture and bends toward the humidity response layer; during the humidity drive process, the metal carbide MXene film absorbs moisture and bends toward the photothermal response layer. The light, heat and humidity driving directions of the metal carbide MXene film itself are consistent with the overall driving direction of the entire "sandwich" structure driver, playing an auxiliary role in further strengthening the driving. The transition metal carbide MXene involved includes but is not limited to products prepared or commercially available using methods such as chemical exfoliation.

[0040] For example, chemical exfoliation is used to prepare transition metal carbide MXenes, including: Ti 3 AlC 2 Add LiF and HCl mixed solution, react at 45 °C for 10-24 h, centrifuge and wash the precipitate, then add ethanol to the precipitate to achieve intercalation, then perform ultrasonic treatment in an ice bath for 0.5-1 h, and separate the precipitate by centrifugation, add water to the precipitate and ultrasonically treat it for 10-20 min, finally, obtain a colloidal suspension of transition metal carbide MXene nanosheets from the supernatant by centrifugation.

[0041] The present invention provides a method for preparing any of the composite fiber membranes, comprising:

[0042] (1) mixing a photothermal filler, a hydrophobic polymer, and a solvent, stirring and mixing to obtain a spinning solution, and spinning to obtain a photothermal response layer;

[0043] (2) Preparation of conductive films;

[0044] (3) mixing the hygroscopic filler, the hydrophilic polymer, and the solvent, stirring and mixing to obtain a spinning solution, and spinning to obtain a humidity responsive layer;

[0045] (4) stacking and compounding to obtain a composite fiber membrane, wherein the conductive film in the composite fiber membrane is arranged between the photothermal response layer and the humidity response layer.

[0046] Preferably, the solvent in steps (1) and (3) comprises one or more of water, ethanol, methanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, chloroform, acetone, toluene, pyridine and dichlorothionyl.

[0047] In the step (1), the concentration of the hydrophobic polymer in the spinning solution is 1 wt%-30 wt%, and more preferably 5 wt%-10 wt%.

[0048] In the step (3), the concentration of the hydrophilic polymer in the spinning solution is 1 wt%-30 wt%, and more preferably 5 wt%-10 wt%.

[0049] The spinning methods in steps (1) and (3) include one or more of dry spinning, wet spinning, electrospinning, microfluidic spinning, melt-blowing spinning, and Czochralski spinning.

[0050] The preparation of the conductive film in step (2) includes one or more of physical vapor deposition, chemical vapor deposition, solution method, casting method, spin coating method, and vacuum filtration method.

[0051] The compounding method in step (4) includes one or more of heat pressing, adhesive bonding, and physical cross-linking interlocking.

[0052] Further preferably, the composite method is hot pressing. The advantages of hot pressing process are integrated forming, adjustable thickness, firm bonding interface and no redundant adhesive layer to affect driving performance.

[0053] Preferably, the hot pressing time is 20-40 s, the temperature is 70-90° C., and the pressure is 10-20 MPa. More preferably, the hot pressing time is 25-35 s, the temperature is 75-85° C., and the pressure is 13-17 MPa.

[0054] The adhesive bonding is performed by using an adhesive to bond the layers layer by layer. The adhesive is water-based polyurethane with a solid content of 25-40%.

[0055] The present invention provides an electromagnetic wave sensing and shielding driver, wherein the driver comprises any of the composite fiber membranes.

[0056] The present invention provides an application of any of the composite fiber membranes or the electromagnetic wave sensing and shielding driver in the fields of electromagnetic wave shielding, electromagnetic wave sensing, smart wearable devices, flexible electronic devices, medical diagnosis, high-risk environment warning, and soft robots.

[0057] Beneficial Effects

[0058] (1) The composite fiber membrane prepared by the present invention can be used as an electromagnetic wave sensing and shielding driver. Its porous structure and high specific surface area allow rapid absorption and migration of various stimulus factors (light, heat, and moisture). At the same time, the fiber-based composite membrane has micro-nanoscale adjustability and customizability, and it is easy to precisely control the fiber diameter, density, orientation, and interlayer thickness ratio by adjusting the process parameters.

[0059] (2) The composite fiber membrane prepared by the present invention is used as an electromagnetic wave sensing and shielding driver. The multi-interface characteristics provided by its porous structure can reflect the electromagnetic wave multiple times when the electromagnetic wave is incident, thereby increasing the absorption ratio of the electromagnetic wave.

[0060] (3) The composite fiber membrane prepared by the present invention is used as an electromagnetic wave sensing and shielding driver, in which the functional filler (such as hydrophilically modified ferroferric oxide) can simultaneously provide the triple functions of photothermal conversion, moisture absorption, and hysteresis loss, making the entire driver preparation process simpler and less costly.

[0061] (4) The composite fiber membrane prepared in the present invention serves as an electromagnetic wave sensing and shielding actuator, integrating for the first time the three consecutive functions of sensing electromagnetic waves, triggering actuator deformation, and shielding electromagnetic waves, which has never been discovered before.

[0062] (5) The composite fiber membrane prepared by the present invention serves as an electromagnetic wave sensing and shielding driver, has the function of deformation under light, heat and moisture stimulation, can sense the intensity of electromagnetic wave radiation and shield electromagnetic wave pollution, and also has the advantages of light weight, flexibility and strong processability. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a structural scanning electron microscope image of the sandwich structure actuator described in Example 1;

[0064] Figure 2 It is a schematic diagram of calculating the curvature change of the present invention;

[0065] Figure 3 The bending state of the driver assembled in Example 1 under different irradiation times of infrared light and different humidity environments;

[0066] Figure 4 It is a graph of different induced voltage signals generated by the driver assembled in Example 1 when the electromagnetic wave intensity in the environment is changed;

[0067] Figure 5 is a graph showing the electromagnetic wave shielding effectiveness of the driver assembled in Example 1 in the X-band;

[0068] Figure 6 is a comparison chart of the electromagnetic shielding effectiveness between Example 1 and Example 2;

[0069] Figure 7 is a comparison chart of Example 1 and Example 3 in terms of photothermal drive and humidity drive;

[0070] Figure 8 is a comparison diagram of the electromagnetic wave perception sensitivity between Example 1 and Example 4;

[0071] Fig. 9 is a comparison chart of Example 1 and Example 5 in terms of photothermal drive and humidity drive;

[0072] Fig.10 It is a comparison chart of Example 1 and Example 6 in terms of the bonding strength between the composite fiber membrane layers. DETAILED DESCRIPTION

[0073] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0074] Polyvinylidene fluoride: molecular weight is 1 million, purchased from Qingdao Nuokang Environmental Protection Technology Co., Ltd.

[0075] Polyvinyl pyrrolidone: molecular weight is 1.3 million, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0076] N,N-dimethylformamide, acetone and ethanol: all analytically pure, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0077] The preparation method of the hydrophilically modified ferroferric oxide and transition metal carbide MXene selected in the embodiment is:

[0078] Hydrophilic modification of ferroferric oxide: First, 8.2 g FeCl 3 6H 2 O was dissolved in 50 mL of deionized water, and 5.6 g of FeSO 4 7H 2 O, ultrasonically dissolve. Secondly, transfer the above solution to a 250 mL three-necked flask, heat it in a 45°C water bath, dissolve 5.6 g of NaOH in 25 mL of deionized water and add it to the three-necked flask, and heat it at 80°C and 500 r min. -1 After the reaction was completed, the mixture was centrifuged to extract the precipitate, and the product was repeatedly washed with deionized water until it was neutral and dried.

[0079] Transition metal carbide MXene: First, 1.6 g of LiF and 40 mL of HCl were mixed to prepare a LiF / HCl solution. Then, 1 g of Ti 3 AlC 2 The powder was gradually added to the mixed solution and reacted at 45 °C for 24 h to complete the removal of the aluminum layer in the MAX phase. After that, the precipitate was separated by centrifugation and centrifuged with deionized water several times (3500 r / min, 5 min each time) until the pH value of the mixture was neutral. Next, ethanol was added to the precipitate to achieve intercalation, and then the mixture was sonicated for 1 h in an ice bath and the precipitate was separated by centrifugation (5000 r / min, 30 min). In order to promote the stacking of MXene sheets, deionized water was added to the precipitate and sonicated for 20 min. Finally, a colloidal suspension of transition metal carbide MXene nanosheets was obtained from the supernatant by centrifugation (3500 r / min, 5 min).

[0080] Electromagnetic wave perception performance test method:

[0081] The conductive layer of the driver is connected to an electrometer for induced voltage collection. The electromagnetic wave transmitter is connected to the AC voltage regulator and placed near the driver. When the electromagnetic wave transmitter is working, the alternating electromagnetic field in the surrounding area will induce an electric potential on the driver and be detected as a voltage signal. By continuously adjusting the voltage of the AC voltage regulator, the generated induced voltage is recorded as a detection signal of the electromagnetic wave intensity.

[0082] Electromagnetic wave shielding performance test method:

[0083] Refer to GB / T 30142-2013.

[0084] Drive performance test method:

[0085] (1) The sample size is 2 cm × 0.5 cm. The photothermal stimulation source is provided by an infrared lamp. The test environment is a closed acrylic box. The infrared lamp switch is triggered by a button to achieve thermal radiation to the driver. The power of the infrared lamp is 250 W, the irradiation distance is 20 cm, and the irradiation time is 10 s. A high-definition camera is used to record the deformation effect of the driver under different irradiation times.

[0086] (2) The sample size is 2 cm × 0.5 cm. The humidity stimulus source is provided by a humidifier. The test environment is a closed acrylic box. The humidity in the closed acrylic box is controlled by pressing a button to trigger the humidifier switch. The relative humidity increases from 20% to 80%. During this period, a humidity sensor is used to provide accurate humidity data support. A high-definition camera is used to record the deformation effect of the actuator under different humidity conditions.

[0087] (3) The angle perpendicular to the horizontal plane is defined as 0°, the right side of the angle is defined as a negative angle, and the left side is defined as a positive angle, such as Figure 2 As shown, the recording drive r before stimulation 1 and θ 1 , after stimulation 2 and θ 2 , in order to quantify the driving behavior and performance of the actuator, and calculate the curvature K before stimulation 1 and the curvature K after stimulation 2 , use K 2 Subtract K 1 The difference is recorded as the curvature change span to evaluate the driving effect. K can be expressed as:

[0088] K=1 / r= (θ×π) / (180°×L),

[0089] Where r: radius of curvature (unit: cm); θ: angle of change (unit: °); L: arc length (unit: cm)

[0090] Bonding fastness determination method:

[0091] Place the driver at room temperature for 10 days and observe its cross section with the naked eye to see if there is any delamination.

[0092] Example 1

[0093] In this embodiment, an electromagnetic wave sensing and shielding driver is provided, and the preparation method is as follows:

[0094] (1) Preparation of photothermal response layer: The thermal expansion coefficient is 2.2×10 -3 K -1 The polyvinylidene fluoride was dissolved in N, N-dimethylformamide / acetone with a mass ratio of 7:3 to prepare a 10 wt% spinning solution. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as photothermal fillers with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane was prepared by electrospinning with a high propulsion speed.

[0095] (2) Preparation of conductive layer: The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane of step (1) was used as a filter membrane, and a layer of transition metal carbide MXene film was physically adsorbed on it by vacuum filtration. The concentration of the transition metal carbide MXene dispersion was 1 mg mL -1 , the solvent is deionized water, and the conductivity of the conductive layer is 3282 S / cm.

[0096] (3) Preparation of humidity response layer: The thermal expansion coefficient is -1.2×10 -3 K -1 The polyvinyl pyrrolidone was dissolved in ethanol / deionized water with a mass ratio of 7:3 to prepare a spinning solution of 10 wt%. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as a hygroscopic filler with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinyl pyrrolidone fiber membrane was prepared by electrospinning with a high propulsion speed.

[0097] (4) Assembling the driver: stacking the photothermal response layer, the conductive layer, and the humidity response layer in order, and forming a "sandwich" driver by hot pressing ( Figure 1 ), the hot pressing time is 30 s, the temperature is 80℃, and the pressure is 15 MPa. The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 2:1:4, and the total thickness of the composite fiber membrane is 70 μm.

[0098] like Figure 3 As shown, the driving performance: the curvature change span of photothermal driving is 5.7 cm -1 , the humidity-driven curvature change span is 5.8 cm -1 ,like Figure 4 As shown in Figure 2, the maximum induced voltage generated by the electromagnetic wave sensing performance is 0.7 V. Figure 5 As shown, the average electromagnetic shielding effectiveness of the X-band is 55 dB. The driver made by this hot pressing process has high bonding strength and is not prone to delamination ( Fig.10 ).

[0099] Example 2

[0100] In this embodiment, an electromagnetic wave sensing and shielding driver is provided, and the preparation method is as follows:

[0101] (1) Preparation of photothermal response layer: The thermal expansion coefficient is 2.2×10 -3 K -1 The polyvinylidene fluoride was dissolved in N, N-dimethylformamide / acetone with a mass ratio of 7:3 to prepare a 10 wt% spinning solution. Carbon nanotubes were added to the spinning solution as photothermal fillers with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 Advancing speed process, electrospinning preparation of carbon nanotube / polyvinylidene fluoride fiber membrane.

[0102] (2) Preparation of conductive layer: The carbon nanotube / polyvinylidene fluoride fiber membrane of step (1) was used as a filter membrane, and a layer of transition metal carbide MXene film was physically adsorbed on it by vacuum filtration. The concentration of the transition metal carbide MXene dispersion was 1 mg mL -1 , the solvent is deionized water, and the conductivity of the conductive layer is 3282 S / cm.

[0103] (3) Preparation of humidity response layer: The thermal expansion coefficient is -1.2×10 -3 K -1 Polyvinyl pyrrolidone was dissolved in ethanol / deionized water with a mass ratio of 7:3 to prepare a spinning solution of 10 wt%. Silica nanoparticles were added to the spinning solution as a hygroscopic filler with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 Electrospinning of silica / polyvinyl pyrrolidone fiber membranes.

[0104] (4) Assembling the actuator: The photothermal response layer, the conductive layer, and the humidity response layer are stacked in order and formed into an actuator with a "sandwich" structure by hot pressing. The hot pressing time is 30 s, the temperature is 80°C, and the pressure is 15 MPa. The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 2:1:4, and the total thickness of the composite fiber membrane is 70 μm.

[0105] Driving performance: The curvature variation span of photothermal driving is 5.5 cm -1 , the humidity-driven curvature change span is 5.6 cm -1 , the maximum induced voltage generated by electromagnetic wave sensing performance: 0.7 V, the average electromagnetic shielding effectiveness of the X-band: 47 dB ( Figure 6 ).

[0106] Example 3

[0107] In this embodiment, an electromagnetic wave sensing and shielding driver is provided, and the preparation method is as follows:

[0108] (1) Preparation of photothermal response layer: The thermal expansion coefficient is 2.2×10 -3 K -1 The polyvinylidene fluoride was dissolved in N, N-dimethylformamide / acetone with a mass ratio of 7:3 to prepare a 10 wt% spinning solution. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as photothermal fillers with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane was prepared by electrospinning with a high propulsion speed.

[0109] (2) Preparation of conductive layer: The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane in step (1) was used as a filter membrane, and a layer of transition metal carbide MXene film was physically adsorbed on it by vacuum filtration. The concentration of the transition metal carbide MXene dispersion was 1 mg mL -1 , the solvent is deionized water, and the conductivity of the conductive layer is 3282 S / cm.

[0110] (3) Preparation of humidity response layer: The thermal expansion coefficient is -1.2×10 -3 K -1 The polyvinyl pyrrolidone was dissolved in ethanol / deionized water with a mass ratio of 7:3 to prepare a spinning solution of 10 wt%. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as a hygroscopic filler with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinyl pyrrolidone fiber membrane was prepared by electrospinning with a high propulsion speed.

[0111] (4) Assembling the driver: The photothermal response layer, the conductive layer, and the humidity response layer are stacked in order, and the layers are bonded layer by layer using an adhesive to form a "sandwich" structure driver. The adhesive is water-based polyurethane with a solid content of 32%. The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 2:1:4, and the total thickness of the composite fiber membrane is 70 μm.

[0112] Driving performance: The curvature variation span of photothermal driving is 5.1 cm -1 , the humidity-driven curvature change span is 5.2 cm -1 ( Figure 7 ), the maximum induced voltage generated by the electromagnetic wave perception performance: 0.7 V, the average electromagnetic shielding effectiveness in the X-band: 55 dB.

[0113] Example 4

[0114] In this embodiment, an electromagnetic wave sensing and shielding driver is provided, and the preparation method is as follows:

[0115] (1) Preparation of photothermal response layer: The thermal expansion coefficient is 2.2×10 -3 K -1The polyvinylidene fluoride was dissolved in N, N-dimethylformamide / acetone with a mass ratio of 7:3 to prepare a 10 wt% spinning solution. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as photothermal fillers with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane was prepared by electrospinning with a high propulsion speed.

[0116] (2) Preparation of conductive layer: The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane prepared in step (1) was used as a substrate, and a layer of silver nanowire film was sprayed on it using a spray gun. The concentration of the silver nanowire dispersion was 5 mg mL -1 , the solvent is isopropyl alcohol, and the conductivity of the conductive layer is 2782 S / cm.

[0117] (3) Preparation of humidity response layer: The thermal expansion coefficient is -1.2×10 -3 K -1 The polyvinyl pyrrolidone was dissolved in ethanol / deionized water with a mass ratio of 7:3 to prepare a spinning solution of 10 wt%. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as a hygroscopic filler with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinyl pyrrolidone fiber membrane was prepared by electrospinning with a high propulsion speed.

[0118] (4) Assembling the actuator: The photothermal response layer, the conductive layer, and the humidity response layer are stacked in order and formed into an actuator with a "sandwich" structure by hot pressing. The hot pressing time is 30 s, the temperature is 80°C, and the pressure is 15 MPa. The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 2:1:4, and the total thickness of the composite fiber membrane is 70 μm.

[0119] Driving performance: The curvature variation span of photothermal driving is 5.4 cm -1 , the humidity-driven curvature change span is 5.5 cm -1 , the maximum induced voltage generated by electromagnetic wave sensing performance: 0.5 V ( Figure 8 ), average electromagnetic shielding effectiveness in the X-band: 49dB.

[0120] Example 5

[0121] In this embodiment, an electromagnetic wave sensing and shielding driver is provided, and the preparation method is as follows:

[0122] (1) Preparation of photothermal response layer: The thermal expansion coefficient is 2.5×10 -4 K -1 The polyurethane was dissolved in N,N-dimethylformamide to prepare a 10 wt% spinning solution. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as photothermal fillers, with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The process of advancing speed was used to prepare hydrophilic modified ferroferric oxide / polyurethane fiber membrane by electrospinning.

[0123] (2) Preparation of conductive layer: The hydrophilic modified ferroferric oxide / polyurethane fiber membrane in step (1) was used as a filter membrane, and a layer of transition metal carbide MXene film was physically adsorbed on it by vacuum filtration. The concentration of the transition metal carbide MXene dispersion was 1 mg mL -1 , the solvent is deionized water, and the conductivity of the conductive layer is 3282 S / cm.

[0124] (3) Preparation of humidity response layer: The thermal expansion coefficient is -4×10 -4 K -1 The polyethylene oxide was dissolved in ethanol / deionized water with a mass ratio of 1:1 to prepare a spinning solution of 10 wt%. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as a hygroscopic filler with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyethylene oxide fiber membrane was prepared by electrospinning with a high propulsion speed.

[0125] (4) Assembling the actuator: The photothermal response layer, the conductive layer, and the humidity response layer are stacked in order and formed into an actuator with a "sandwich" structure by hot pressing. The hot pressing time is 30 s, the temperature is 80°C, and the pressure is 15 MPa. The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 2:1:4, and the total thickness of the composite fiber membrane is 70 μm.

[0126] Driving performance: The curvature variation span of photothermal driving is 5.0 cm -1 , the humidity-driven curvature change span is 5.1 cm -1 ( Fig. 9 ), the maximum induced voltage generated by the electromagnetic wave perception performance: 0.7 V, the average electromagnetic shielding effectiveness in the X-band: 55 dB.

[0127] Example 6

[0128] In this embodiment, an electromagnetic wave sensing and shielding driver is provided, and the preparation method is as follows:

[0129] (1) Preparation of photothermal response layer: The thermal expansion coefficient is 2.2×10 -3 K -1 The polyvinylidene fluoride was dissolved in N, N-dimethylformamide / acetone with a mass ratio of 7:3 to prepare a 10 wt% spinning solution. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as photothermal fillers with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane was prepared by electrospinning with a high propulsion speed.

[0130] (2) Preparation of conductive layer: The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane prepared in step (1) was used as a filter membrane, and a layer of transition metal carbide MXene film was physically adsorbed on it by vacuum filtration. The concentration of the transition metal carbide MXene dispersion was 1 mg mL -1 , the solvent is deionized water, and the conductivity of the conductive layer is 3282 S / cm.

[0131] (3) Preparation of humidity response layer: The thermal expansion coefficient is -1.2×10 -3 K -1 The polyvinyl pyrrolidone was dissolved in ethanol / deionized water with a mass ratio of 7:3 to prepare a spinning solution of 10 wt%. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as a hygroscopic filler with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinyl pyrrolidone fiber membrane was prepared by electrospinning with a high propulsion speed.

[0132] (4) Assembling the actuator: The photothermal response layer, the conductive layer, and the humidity response layer are stacked in order and formed into an actuator with a "sandwich" structure by hot pressing. The hot pressing time is 20 s, the temperature is 80°C, and the pressure is 10 MPa. The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 3:1:3, and the total thickness of the composite fiber membrane is 105 μm.

[0133] Driving performance: The curvature variation span of photothermal driving is 5.8 cm -1 , the humidity-driven curvature change span is 5.9 cm -1, the maximum induced voltage generated by electromagnetic wave sensing performance: 0.7 V, the average electromagnetic shielding effectiveness of the X-band: 55 dB. Although the bending curvature of the driver is slightly improved after the hot pressing time in the hot pressing process is reduced and the hot pressing pressure is reduced, the bonding strength between the obtained composite fiber membrane layers is not high and delamination is prone to occur ( Fig.10 ).

[0134] Comparative Example 1

[0135] In this comparative example, an electromagnetic wave sensing and shielding driver is provided, and the preparation method is as follows:

[0136] (1) Preparation of photothermal response layer: The thermal expansion coefficient is 2.2×10 -3 K -1 The polyvinylidene fluoride was dissolved in N, N-dimethylformamide / acetone with a mass ratio of 7:3 to prepare a 10 wt% spinning solution. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as photothermal fillers with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane was prepared by electrospinning with a high propulsion speed.

[0137] (2) Preparation of the intermediate layer: The hydrophilic modified ferroferric oxide / polyvinylidene fluoride fiber membrane prepared in step (1) was used as a filter membrane, and a layer of cellulose nanofiber film was physically adsorbed on the membrane by vacuum filtration. The concentration of the cellulose nanofiber dispersion was 1 mg mL -1 , the solvent is deionized water, and the middle layer is non-conductive.

[0138] (3) Preparation of humidity response layer: The thermal expansion coefficient is -1.2×10 -3 K -1 The polyvinyl pyrrolidone was dissolved in ethanol / deionized water with a mass ratio of 7:3 to prepare a spinning solution of 10 wt%. Hydrophilic modified ferroferric oxide nanoparticles were added to the spinning solution as a hygroscopic filler with a filler to polymer ratio of 1:10. After stirring evenly, the spinning solution was heated at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The hydrophilic modified ferroferric oxide / polyvinyl pyrrolidone fiber membrane was prepared by electrospinning with a high propulsion speed.

[0139] (4) Assembling the actuator: The photothermal response layer, the middle layer, and the humidity response layer are stacked in order, and a "sandwich" structure actuator is formed by hot pressing. The hot pressing time is 30 s, the temperature is 80°C, and the pressure is 15 MPa. The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 2:1:4, and the total thickness of the composite fiber membrane is 70 μm.

[0140] Driving performance: The curvature variation span of photothermal driving is 5.5 cm -1 , the humidity-driven curvature change span is 5.6 cm -1 , no electromagnetic wave perception performance, the average electromagnetic shielding effectiveness of the X-band is 4 dB. Therefore, the conductive layer plays a decisive role in electromagnetic wave perception, and also has positive significance for photothermal drive, humidity drive, and electromagnetic shielding performance.

[0141] Comparative Example 2

[0142] In this comparative example, an electromagnetic wave sensing and shielding driver is provided, and the preparation method is as follows:

[0143] (1) Preparation of photothermal response layer: The thermal expansion coefficient is 2.2×10 -3 K -1 The polyvinylidene fluoride was dissolved in N, N-dimethylformamide / acetone with a mass ratio of 7:3 to prepare a 10 wt% spinning solution. The spinning solution was prepared at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 The process of advancing speed and preparing polyvinylidene fluoride fiber membrane by electrospinning.

[0144] (2) Preparation of conductive layer: The polyvinylidene fluoride fiber membrane prepared in step (1) was used as a filter membrane, and a layer of transition metal carbide MXene film was physically adsorbed on it by vacuum filtration. The concentration of the transition metal carbide MXene dispersion was 1 mg mL -1 , the solvent is deionized water, and the conductivity of the conductive layer is 3282 S / cm.

[0145] (3) Preparation of humidity response layer: The thermal expansion coefficient is -1.2×10 -3 K -1 The polyvinyl pyrrolidone was dissolved in ethanol / deionized water with a mass ratio of 7:3 to prepare a 10 wt% spinning solution. The spinning solution was prepared at 15 kV, 15 cm receiving distance, 1500 rpm, and 1 mL h -1 Advancing speed process, electrospinning preparation of polyvinyl pyrrolidone fiber membrane.

[0146] (4) Assembling the actuator: The photothermal response layer, the conductive layer, and the humidity response layer are stacked in order and formed into an actuator with a "sandwich" structure by hot pressing. The hot pressing time is 30 s, the temperature is 80°C, and the pressure is 15 MPa. The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 2:1:4, and the total thickness of the composite fiber membrane is 70 μm.

[0147] Driving performance: The curvature variation span of photothermal driving is 4.4 cm -1 , the humidity-driven curvature change span is 4.5 cm -1 , the maximum induced voltage generated by electromagnetic wave sensing performance: 0.7 V, and the average electromagnetic shielding effectiveness in the X-band: 46 dB. Therefore, the hydrophilic modified ferroferric oxide, which is a photothermal filler and hygroscopic filler, is also a magnetic material. Adding it to the photothermal response layer and the humidity response layer and compounding it with the conductive layer to form a "magnetic-conductive-magnetic sandwich structure" is of great significance for electromagnetic shielding performance and photothermal drive and humidity drive.

Claims

1. A composite fiber membrane, characterized in that: The composite fiber membrane comprises a photothermal response layer, a conductive layer and a humidity response layer in sequence, wherein the photothermal response layer material is a hydrophobic polymer fiber membrane containing photothermal fillers; the humidity response layer material is a hydrophilic polymer fiber membrane containing hygroscopic fillers.

2. The composite fiber membrane according to claim 1, characterized in that: The thickness ratio of the photothermal response layer, the conductive layer, and the humidity response layer is 10:1:1-1:1:10; The mass ratio of the photothermal filler to the hydrophobic polymer in the photothermal response layer is 10:1-1:1000; The mass ratio of the hygroscopic filler to the hydrophilic polymer in the humidity responsive layer is 10:1-1:1000; The electrical conductivity of the conductive layer is greater than 1000 S / m.

3. The composite fiber membrane according to claim 1, characterized in that: The photothermal filler includes one or more of carbon black, graphite, black phosphorus, carbon nanotubes, graphene, graphene oxide, transition metal carbide MXene, polydopamine, a first metal nanomaterial, and a first metal oxide nanomaterial; the hygroscopic filler includes one or more of silica, zeolite, transition metal carbide MXene, graphene, graphene oxide, metal organic frameworks MOFs, covalent organic frameworks COFs, polydopamine, a second metal nanomaterial, and a second metal oxide nanomaterial.

4. The composite fiber membrane according to claim 3, characterized in that: The first metal nanomaterial includes one or more of gold, silver, copper, platinum, and palladium nanomaterials; the first metal oxide nanomaterial includes one or more of manganese dioxide, titanium dioxide, zinc oxide, indium tin oxide, cerium dioxide, ferroferric oxide, and hydrophilically modified ferroferric oxide nanomaterials; The second metal nanomaterial includes one or more of hydrophilically modified silver, hydrophilically modified copper, hydrophilically modified gold, hydrophilically modified titanium, and hydrophilically modified nickel nanomaterials; the second metal oxide nanomaterial includes one or more of aluminum oxide, titanium dioxide, silicon dioxide, manganese dioxide, zinc oxide, and hydrophilically modified ferroferric oxide nanomaterials; The first or second metal nanomaterial, the first or second metal oxide nanomaterial includes zero-dimensional nanoparticles, one-dimensional nanowires or two-dimensional nanosheets.

5. The composite fiber membrane according to claim 1, characterized in that: The hydrophobic polymer fiber membrane includes a hydrophobic thermal expansion polymer fiber membrane; the hydrophilic polymer fiber membrane includes a hydrophilic thermal shrinkage polymer fiber membrane; wherein the hydrophobic thermal expansion polymer includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyester, polyurethane, polylactic acid, styrene-isoprene, and ethylene-vinyl acetate; the hydrophilic thermal shrinkage polymer includes one or more of polyvinyl alcohol, polyacrylic acid, polyethylene glycol, polyvinyl pyrrolidone, polyethylene oxide, and polyacrylonitrile.

6. The composite fiber membrane according to claim 1, characterized in that: The conductive layer material is one or more of zero-dimensional material, one-dimensional material, and two-dimensional material; The zero-dimensional material includes metal nanoparticles; wherein the metal nanoparticles include one or more of gold nanoparticles, platinum nanoparticles, silver nanoparticles, and copper nanoparticles; One-dimensional materials include metal nanowires; The metal nanowires include one or more of gold nanowires, platinum nanowires, silver nanowires, and copper nanowires; The two-dimensional material includes one or more of metal nanosheets and non-metal nanosheets; the metal nanosheets include one or more of gold nanosheets, platinum nanosheets, silver nanosheets, and copper nanosheets; the non-metal nanosheets include one or more of MXene, graphene, graphene oxide, molybdenum disulfide, tungsten disulfide, black scales, and metal organic framework MOF derivatives.

7. A method for preparing the composite fiber membrane according to any one of claims 1 to 6, comprising: (1) mixing a photothermal filler, a hydrophobic polymer, and a solvent, stirring and mixing to obtain a spinning solution, and spinning to obtain a photothermal response layer; (2) Preparation of conductive films; (3) mixing the hygroscopic filler, the hydrophilic polymer, and the solvent, stirring and mixing to obtain a spinning solution, and spinning to obtain a humidity responsive layer; (4) stacking and compounding to obtain a composite fiber membrane; wherein the conductive film in the composite fiber membrane is arranged between the photothermal response layer and the humidity response layer.

8. The preparation method according to claim 7, characterized in that: The solvent in steps (1) and (3) includes one or more of water, ethanol, methanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, chloroform, acetone, toluene, pyridine, and dichlorothionyl; In the step (1), the concentration of the hydrophobic polymer in the spinning solution is 1 wt%-30 wt%; In step (3), the concentration of the hydrophilic polymer in the spinning solution is 1 wt%-30 wt%; The preparation of the conductive film in step (2) includes one or more of physical vapor deposition, chemical vapor deposition, solution method, casting method, spin coating method, and vacuum filtration method; The compounding method in step (4) includes one or more of heat pressing, adhesive bonding, and physical cross-linking interlocking.

9. An electromagnetic wave sensing and shielding driver, characterized in that: The driver comprises the composite fiber membrane according to any one of claims 1-7.

10. An application of the composite fiber membrane according to any one of claims 1 to 6 or the electromagnetic wave sensing and shielding driver according to claim 9 in the fields of electromagnetic wave shielding, electromagnetic wave sensing, flexible electronic devices, smart wearable devices, biomedical diagnosis, environmental monitoring and early warning, and soft robots.

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