Elastic multifunctional wave-absorbing fabric based on metamaterial structure and preparation method thereof

Abstract

The application discloses an elastic multifunctional wave-absorbing fabric based on a metamaterial structure and a preparation method thereof. The former comprises: a preset number of single-layer fabrics which are overlapped in the same position, each single-layer fabric comprising a TPU fiber weaving area and a plurality of AgNWs / MXene-TPU@TPU composite fiber weaving areas which are periodically arranged and are all preset patterns; the two areas are woven by using TPU fibers and AgNWs / MXene-TPU@TPU composite fibers respectively through a warp knitting machine; the two fibers are obtained based on a wet spinning process; the composite fiber is a coaxial structure, comprising an AgNWs / MXene-TPU core and a TPU shell; different composite fibers are capacitively pressure-sensed by junction capacitance at the weaving connection, and a capacitive pressure sensor array is formed. The application has high wave-absorbing efficiency, good skin-friendliness and air permeability, good tensile and strain recovery performance, and can realize whole-plane pressure sensing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electromagnetic protection, and particularly relates to an elastic multifunctional wave-absorbing fabric based on a metamaterial structure and a preparation method thereof. BACKGROUND

[0002] With the vigorous development of wearable devices, in order to better perceive, transmit and process the activity information of humans or animals, efficiently realize physiological monitoring, environmental perception, gesture recognition and other intelligent functions, a flexible electronic system of the wearable device gradually integrates a large number of electronic elements in high density to meet the above application requirements. These integrated electronic elements can include active devices such as thin film transistors, processors and memory ICs, can include passive elements such as capacitors, inductors and resistors, and can also include power supplies such as flexible batteries and the like. However, while the electronic elements are highly integrated, serious electromagnetic interference will occur between devices, which can cause some normally working systems to malfunction, and the reliability of the flexible electronic system faces certain risks. In addition, excessive disordered electromagnetic wave interference can also cause certain harm to human health, in addition to causing a series of diseases including cancer, Alzheimer's disease and the like, it can also cause people to have palpitations, nightmares, dizziness and weakness, or cause more serious psychological problems. In order to effectively prevent and treat diseases and protect health, electromagnetic protection materials such as wave-absorbing materials can be used to eliminate electromagnetic hazards. According to the electromagnetic shielding theory, absorbing electromagnetic waves through dielectric loss can not only effectively reduce the electromagnetic interference generated by the devices, but also avoid the secondary pollution caused by the reflected electromagnetic waves.

[0003] Electromagnetic metamaterial is a new type of wave-absorbing material that has attracted much attention at present. It is an electromagnetic medium composed of periodically arranged microstructures designed by humans. In the early design, through continuous optimization and improvement of the microstructure, the metamaterial can exhibit different singular electromagnetic phenomena in the field of electromagnetic wave absorption. At the same time, compared with traditional wave-absorbing materials, the electromagnetic metamaterial can exhibit the characteristics of light weight, small material consumption and superior wave-absorbing performance.

[0004] Skin is the main organ for humans to obtain touch, and can sense pressure and complex stimuli from the outside world. In order to simulate the touch of human skin, wearable pressure sensing devices have emerged, which can perceive environmental stimuli and respond to the stimuli in the environment in a timely manner, and are one of the indispensable key sensors in wearable devices. In order to improve the comfort of wearable devices, the pressure sensing device should have excellent stretchability, breathability and mechanical structure stability, and should also have a relatively sensitive pressure sensing function.

[0005] Currently, there are some existing researches on materials with both wave-absorbing and pressure-sensing functions. For example, Huang from Jiangnan University published a work in ACS AMI, “Polyimide Nanofiber-Reinforced Ti3C2T x Both the work of Huang from Jiangnan University and the research of Zhang from Beijing University of Chemical Technology in Small, “Multifunctional, Superelastic, and Lightweight MXene / Polyimide Aerogels”, use polyimide (PI) to carry MXene and adopt freeze-drying process to construct lightweight and stable elastic aerogel wave-absorbing bodies. These two wave-absorbing bodies with different microstructures not only have good wave-absorbing performance, but also show excellent pressure-sensing function, including wide pressure detection range, high piezoresistive sensitivity, and extremely low detection limit. However, due to the loose structure of aerogel, the material is easily damaged by mechanical deformation, and its mechanical stability needs to be further improved. In addition, the aerogel carries a large amount of two-dimensional materials, and its air permeability and comfort cannot meet the needs of wearable devices.

[0006] Since fabric is one of the most common and comfortable materials in contact with human skin, it has good flexibility, air permeability, and mechanical stability. Therefore, fabric with wave-absorbing and pressure-sensing functions is expected to solve the above problems.

[0007] In the existing technology, the Chinese invention patent application with application number 202111294852.2 proposes a preparation method and application of a periodic braided electromagnetic wave-absorbing material with multifunction, high-temperature resistance, and wide-band absorption. This method uses algorithms and simulations to guide the construction of wave-absorbing fabric with periodic macrostructure, but it does not have capacitive sensing function and cannot effectively monitor the pressure on the plane. The Chinese invention patent application with application number 201910866280.7 proposes a multifunctional intelligent fiber or fabric. The obtained intelligent fiber and fabric not only have high mechanical properties and electrical conductivity, but also can realize photothermal, electrothermal, and mechanical sensing performance. However, the mechanical sensing of this fabric uses resistance type sensing method, and it also does not have the ability to comprehensively detect the pressure on each point of the plane.

[0008] Therefore, for wearable devices, how to construct electromagnetic shielding materials with high wave absorption efficiency, good skin-friendliness and air permeability, and excellent stretchability while integrating better pressure sensing function on the plane is one of the emerging and important research directions in the field. SUMMARY

[0009] In order to solve the above problems existing in the prior art, the present application provides an elastic multifunctional wave-absorbing fabric based on a metamaterial structure and a preparation method thereof. The technical problem to be solved by the present application is solved by the following technical scheme:

[0010] In a first aspect, the present application provides an elastic multifunctional wave-absorbing fabric based on a metamaterial structure, comprising:

[0011] The preset number of single-layer fabrics overlapped on the same position, each single-layer fabric comprising a TPU fiber weaving area and a plurality of AgNWs / MXene-TPU@TPU composite fiber weaving areas arranged periodically and each being a preset pattern;

[0012] The TPU fiber weaving area and the AgNWs / MXene-TPU@composite TPU fiber weaving area are respectively woven by TPU fiber and AgNWs / MXene-TPU@TPU composite fiber using a warp knitting machine; the TPU fiber and the AgNWs / MXene-TPU@TPU composite fiber are obtained based on a wet spinning process; the AgNWs / MXene-TPU@TPU composite fiber has a coaxial structure, comprising an AgNWs / MXene-TPU core and a TPU shell; at the weaving connection of different AgNWs / MXene-TPU@TPU composite fibers in the warp and weft directions, a junction capacitor formed by an upper AgNWs / MXene-TPU as an upper electrode, a middle TPU as a dielectric and a lower AgNWs / MXene-TPU as a lower electrode performs capacitive pressure sensing detection, and an array formed by the junction capacitors of all the weaving connection places forms a capacitive pressure sensor array.

[0013] In an embodiment of the present application, the diameter of the TPU fiber and the AgNWs / MXene-TPU core is 100-900 um; the thickness of the TPU shell is 100-250 um.

[0014] In an embodiment of the present application, the preset pattern comprises:

[0015] A mouth-shaped pattern, a back-shaped pattern, a cross-shaped pattern and a circular ring-shaped pattern.

[0016] In an embodiment of the present application, the elastic multifunctional wave-absorbing fabric based on the metamaterial structure has a wave-absorbing frequency band of 8-18 GHz, and a maximum reflection loss of-20 to-35 dB.

[0017] In an embodiment of the present application, when the preset pattern is a mouth-shaped pattern, in each mouth-shaped unit corresponding to the AgNWs / MXene-TPU@TPU composite fiber weaving area, the outer square has a side length of 3.0-18.0 mm, the inner square has a side length of 2.0-16.0 mm, and the distance between adjacent mouth-shaped units is the same and is 0.5-15.0 mm; the elastic multifunctional wave-absorbing fabric based on the metamaterial structure has a thickness of 1-5 mm.

[0018] In a second aspect, an embodiment of the present application provides a preparation method of an elastic multifunctional wave-absorbing fabric based on a metamaterial structure, the method comprising:

[0019] synthesizing an AgNWs dispersion liquid;

[0020] synthesizing an MXene dispersion liquid;

[0021] using the AgNWs dispersion liquid, the MXene dispersion liquid, and TPU to prepare an AgNWs / MXene-TPU spinning liquid, and using TPU to prepare a TPU spinning liquid;

[0022] using the AgNWs / MXene-TPU spinning liquid and the TPU spinning liquid to obtain AgNWs / MXene-TPU primary fibers and TPU fibers by using a wet spinning process, respectively; and using the AgNWs / MXene-TPU primary fibers to be wrapped with a layer of TPU by using a dip coating process to form a coaxial structure, thereby obtaining AgNWs / MXene-TPU@TPU composite fibers;

[0023] using the AgNWs / MXene-TPU@TPU composite fibers and the TPU fibers as raw materials to perform patterned weaving by using a weaving machine according to structure parameters obtained from a finite element simulation performed in advance, thereby obtaining a single-layer fabric; and stacking the same positions of a preset number of layers of single-layer fabrics one on top of another, thereby obtaining an elastic multifunctional wave-absorbing fabric based on a metamaterial structure; wherein the structure parameters represent parameter information of a metamaterial structure corresponding to the single-layer fabric; and the single-layer fabric comprises a TPU fiber weaving area and a plurality of AgNWs / MXene-TPU@TPU composite fiber weaving areas arranged periodically and in a preset pattern.

[0024] In an embodiment of the present application, the AgNWs dispersion liquid is synthesized by using the following steps:

[0025] Silver nitrate AgNO3 is used as a silver source, polyvinylpyrrolidone PVP is used as a coating agent, ethylene glycol EG is used as a solvent and a reducing agent, sodium chloride NaCl and sodium bromide NaBr are used as nucleating agents, silver nanowires AgNWs are synthesized by a polyol method at a certain temperature; and the synthesized AgNWs are filtered and dispersed to prepare an AgNWs dispersion liquid with a first concentration.

[0026] In an embodiment of the present application, the synthesized MXene dispersion liquid comprises:

[0027] HCl / LiF is obtained as an etching liquid;

[0028] MAX phase Ti3AlC2 powder is added to the etching liquid, and after sufficient etching, the precipitate is obtained by centrifugation, and the extracted precipitate is dispersed in water to prepare a MXene dispersion liquid with a second concentration.

[0029] In an embodiment of the present application, the AgNWs / MXene-TPU spinning liquid is prepared by using the AgNWs dispersion liquid, the MXene dispersion liquid and TPU; and the TPU spinning liquid is prepared by using TPU, comprising:

[0030] The TPU solution solvent is added to the MXene dispersion liquid, the AgNWs dispersion liquid is added, and after uniform stirring, a certain amount of TPU particles are added, and the AgNWs / MXene-TPU spinning liquid is obtained by stirring and dissolving;

[0031] A certain amount of TPU particles are added to the TPU solution solvent and stirred and dissolved to obtain the TPU spinning liquid.

[0032] In an embodiment of the present application, the AgNWs / MXene-TPU spinning liquid and the TPU spinning liquid are respectively prepared by using a wet spinning process to obtain AgNWs / MXene-TPU as-spun fibers and TPU fibers; and the AgNWs / MXene-TPU as-spun fibers are wrapped with a layer of TPU by using a dip coating process to form a coaxial structure, and the AgNWs / MXene-TPU@TPU composite fiber is obtained, comprising:

[0033] The AgNWs / MXene-TPU spinning liquid and the TPU spinning liquid are respectively added to needle tubes, and are respectively pushed out through a spinning nozzle at a respective preset speed, and are shaped by a coagulation bath to obtain AgNWs / MXene-TPU as-spun fibers and TPU fibers, respectively;

[0034] The AgNWs / MXene-TPU as-spun fibers are dip coated in the TPU spinning liquid for multiple times, so that a layer of TPU is wrapped outside to form a coaxial structure, and the AgNWs / MXene-TPU@TPU composite fiber is obtained.

[0035] The embodiment of the present application provides an elastic multifunctional wave-absorbing fabric based on a metamaterial structure and a preparation method thereof, and has the following beneficial effects:

[0036] 1. The elastic multifunctional wave-absorbing fabric of the embodiment of the present application adopts an electromagnetic metamaterial structure, can not only reduce the use of functional materials, but also improve the wave-absorbing performance of the fabric. Meanwhile, the fabric fibers, namely, TPU fibers and AgNWs / MXene-TPU@TPU composite fibers, are prepared based on a wet spinning process, the process can facilitate large-scale production, and meanwhile, the process can realize fine weaving of the metamaterial pattern. In addition, the elastic wave-absorbing body of the whole fabric can meet the demand of skin-friendly and breathable materials of wearable devices, and can provide a better comfortable experience for users.

[0037] 2. As a wave-absorbing and pressure-sensing functional material, the embodiment of the present application adopts MXene to carry AgNWs to prepare AgNWs / MXene-TPU@TPU composite fibers, which can enhance the overall electromagnetic wave conduction loss to a certain extent. Meanwhile, AgNWs, as a good one-dimensional nanometer conductor, can provide an additional conductive channel for the MXene system after being introduced, bridge the two-dimensional MXene sheets, and form a more abundant conductive grid. The two-dimensional MXene can be effectively enhanced in the stability of the conductive network under stretching, and the working range of the pressure sensor can be widened. In addition, TPU, as an adhesive, can not only effectively assemble the nanomaterials and provide a stable mechanical structure, but also can further intensify the absorption loss of electromagnetic waves through the interfacial polarization effect between MXene and AgNWs, and effectively improve the electromagnetic wave absorption capacity of the wave-absorbing fabric.

[0038] 3. Compared with a traditional flexible resistance sensor, the embodiment of the present application proposes a fiber structure of a capacitive sensor on the basis of meeting the wave-absorbing, and prepares AgNWs / MXene-TPU@TPU composite fibers. In the pattern area, the AgNWs / MXene-TPU@TPU composite fibers are connected between nodes, and the upper AgNWs / MXene-TPU as an upper electrode, the middle TPU as a dielectric and the lower AgNWs / MXene-TPU as a lower electrode form a node capacitor. When external pressure acts, the upper and lower electrodes and the dielectric are deformed, the distance between the upper and lower electrodes changes, thereby causing the capacitance change of the capacitive sensor, and the detection of the pressure is completed. Meanwhile, a plurality of node capacitors on the plane are connected in series and in parallel, thereby forming a sensor array in one step. Compared with the original single capacitive sensing structure, the capacitive pressure sensor array formed by the embodiment of the present application can realize the pressure sensing of the whole plane, realize the stress distribution detection, and expand the realization range of the sensor.

[0039] 4. The AgNWs / MXene-TPU@TPU composite fiber uses AgNWs / MXene-TPU composite material as the core, and TPU as the shell, which not only retains the good conductivity of AgNWs and MXene, but also retains the elasticity of TPU itself, greatly improving the tensile capacity of the composite fiber. Moreover, since TPU still has good recovery ability under large strain conditions, the TPU shell can help the fiber as a whole to recover the complete conductive network as soon as possible and best after removing the strain, thereby improving the pressure sensor stability. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A planar structure schematic diagram of a single-layer fabric in an elastic multifunctional wave-absorbing fabric based on a metamaterial structure provided by an embodiment of the present application;

[0041] Figure 2 A schematic diagram of an elastic multifunctional wave-absorbing fabric and a junction capacitor based on a metamaterial structure of an embodiment of the present application;

[0042] Figure 3 A planar structure and circuit topology schematic diagram of a capacitive pressure sensor array of an embodiment of the present application;

[0043] Figure 4 An absorption efficiency diagram of a mouth-shaped wave-absorbing fabric calculated by a finite element method of an embodiment of the present application;

[0044] Figure 5 A flowchart schematic diagram of a preparation method of an elastic multifunctional wave-absorbing fabric based on a metamaterial structure provided by an embodiment of the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0046] The embodiments of the present application aim to provide an elastic wave-absorbing fabric, which is realized by using a periodic electromagnetic metamaterial structure, has excellent microwave wave-absorbing performance, skin-friendly and breathable performance, and tensile performance, and also has good pressure sensing function, and can sensitively detect a small deformation signal.

[0047] In a first aspect, a kind of elastic multifunctional wave-absorbing fabric based on the metamaterial structure provided by the embodiment of the present application is introduced first. The elastic multifunctional wave-absorbing fabric based on the metamaterial structure includes:

[0048] The preset number of single-layer fabrics stacked on each other at the same position, each single-layer fabric comprising a TPU fiber woven area, and a plurality of AgNWs / MXene-TPU@TPU composite fiber woven areas arranged periodically and each being a preset pattern.

[0049] The TPU fiber woven area and the AgNWs / MXene-TPU@composite TPU fiber woven area are respectively woven by a TPU fiber and an AgNWs / MXene-TPU@TPU composite fiber using a warp knitting machine; the TPU fiber and the AgNWs / MXene-TPU@TPU composite fiber are obtained based on a wet spinning process; the AgNWs / MXene-TPU@TPU composite fiber has a coaxial structure, comprising an AgNWs / MXene-TPU core and a TPU shell layer; different AgNWs / MXene-TPU@TPU composite fibers at the woven connection in the warp and weft directions are subjected to capacitive pressure sensing detection by a junction capacitor formed by an upper layer of AgNWs / MXene-TPU as an upper electrode, a middle layer of TPU as a dielectric, and a lower layer of AgNWs / MXene-TPU as a lower electrode, and an array formed by the junction capacitors of all the woven connections forms a capacitive pressure sensor array.

[0050] In an optional embodiment, the diameters of the TPU fiber and the AgNWs / MXene-TPU core are 100-900 um; and the thickness of the TPU shell layer is 100-250 um.

[0051] In an optional embodiment, the preset pattern comprises:

[0052] a mouth-shaped pattern, a back-shaped pattern, a cross-shaped pattern, and a circular ring-shaped pattern.

[0053] Of course, the preset pattern of the embodiments of the present application is not limited to the above-mentioned patterns. For ease of understanding, the embodiments of the present application take the mouth-shaped pattern as an example of the preset pattern, and the plane structure of the single-layer fabric in the elastic multifunctional wave-absorbing fabric based on the metamaterial structure provided by the embodiments of the present application is specifically described hereinafter with reference to Figure 1 The single-layer fabrics obtained by the preset patterns of the remaining shapes are illustrated in combination with Figure 1 It is understood that no further illustration is given here.

[0054] From Figure 1As can be seen in the figure, the largest rectangle represents a single-layer fabric in the elastic multifunctional wave-absorbing fabric based on the metamaterial structure, wherein the white area is a TPU fiber weaving area, which is woven by TPU fibers; and each gray lozenge is an AgNWs / MXene-TPU@TPU composite fiber weaving area, which is named a lozenge unit, and is woven by AgNWs / MXene-TPU@TPU composite fibers. It can be seen that the lozenge units in the single-layer fabric are periodically arranged and have the same shape. Figure 1 In the figure, a represents the side length of the outer square in each lozenge unit, b represents the side length of the inner square in each lozenge unit, and d represents the distance between adjacent lozenge units. At the same time, the thickness of each single-layer fabric can be represented as h. In the embodiment of the present application, the single-layer fabric is realized by using the metamaterial structure of electromagnetic, which not only can reduce the use of functional materials, but also can improve the wave-absorbing performance of the fabric. For the lozenge shape, the structural parameters of the metamaterial structure can include a, b, d, h, etc., which can be obtained by simulation and optimization calculation by using the finite element method. Of course, it can be understood that when the preset pattern is other shapes except the lozenge shape, the structural parameters need to be designed according to the specific pattern. The elastic multifunctional wave-absorbing fabric based on the metamaterial structure in the embodiment of the present application is a multi-layer fabric obtained by overlapping the same positions of a preset number of single-layer fabrics. The preset number is determined by simulation optimization for the purpose of optimizing the performance of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure.

[0055] Referring to Figure 1 It is understood that when weaving the elastic multifunctional wave-absorbing fabric based on the metamaterial structure, the raw materials are TPU fibers and AgNWs / MXene-TPU@TPU composite fibers. When the two raw materials are graphically woven by using an automatic weaving machine or the like, the TPU fiber weaving area is woven by TPU fibers according to the determined structural parameters, and the AgNWs / MXene-TPU@TPU composite fiber weaving area is woven by AgNWs / MXene-TPU@TPU composite fibers.

[0056] The TPU fiber and the AgNWs / MXene-TPU@TPU composite fiber are obtained based on a wet spinning process. The reason is that, among many methods of forming high-quality fiber fabrics, the wet spinning process utilizes the phase change ability of high-concentration colloidal dispersion (i.e., liquid state) into gel fiber assemblies and solid fibers in a coagulation bath, can effectively macro-assemble dispersed low-dimensional nanomaterials into a fiber structure, is a simple process suitable for batch production of wave-absorbing fiber fabrics, and at the same time, the fabric fibers are prepared by using the wet spinning process, which can not only be mass-produced, but also can realize fine weaving of metamaterial patterns. Therefore, the wet spinning process is used as the preparation process of the two fiber raw materials obtained in the embodiments of the present application. In addition, the elastic multifunctional wave-absorbing fabric based on the metamaterial structure obtained based on fiber spinning in the embodiments of the present application is used as an elastic wave-absorbing body of a whole fabric, which can meet the requirements of skin-friendly and breathable materials for wearable devices, and can provide better comfortable experience for users.

[0057] It can be understood that the TPU fiber is prepared from TPU, wherein the TPU is thermoplastic polyurethane. The AgNWs / MXene-TPU@TPU composite fiber is a composite fiber prepared from AgNWs, MXene and TPU, wherein the AgNWs are silver nanowires, and the MXene is two-dimensional titanium carbide. The preparation method of the TPU fiber and the AgNWs / MXene-TPU@TPU composite fiber will be specifically described in the preparation method of an elastic multifunctional wave-absorbing fabric based on a metamaterial structure in the second aspect.

[0058] The obtained AgNWs / MXene-TPU@TPU composite fiber has a coaxial structure, or can also be called a core-shell structure, the outside of which is a TPU shell layer, and the inside of which is an AgNWs / MXene-TPU core body.

[0059] For the structure of the AgNWs / MXene-TPU@TPU composite fiber, please refer to the structure diagram in the lower left dashed box in Figure 1 , wherein, Figure 1The rectangle in the dashed box below and the ellipse above represent the AgNWs / MXene-TPU@TPU composite fibers in two weaving directions, respectively, and it can be understood that the ellipse is a cross-sectional view of the AgNWs / MXene-TPU@TPU composite fiber in the corresponding weaving direction. The black part represents the AgNWs / MXene-TPU core, and the gray area outside the black part represents the TPU shell layer. The two weaving directions include the warp direction and the weft direction. The AgNWs / MXene-TPU@TPU composite fiber of the embodiment of the application uses AgNWs / MXene-TPU composite material as the core and TPU as the shell, which not only retains the good conductivity of AgNWs and MXene, but also retains the elasticity of TPU itself, and can greatly improve the tensile capacity of the AgNWs / MXene-TPU@TPU composite fiber. In addition, since TPU still has good recovery ability under large strain conditions, the TPU shell layer can also help the AgNWs / MXene-TPU@TPU composite fiber as a whole to recover the complete conductive network as soon as possible and best after removing the strain, thereby improving the stability of the pressure sensor.

[0060] As the functional material for wave absorption and pressure sensing of the embodiment of the application, MXene is used to carry AgNWs, which can enhance the overall conduction loss of electromagnetic waves to a certain extent. At the same time, AgNWs, as a good one-dimensional nano conductor, can provide additional conductive channels for the MXene system after being introduced, bridge the two-dimensional MXene sheets, and form a more abundant conductive grid. This can effectively enhance the stability of the conductive network of two-dimensional MXene under stretching, and can broaden the working range of the pressure sensor. In addition, TPU as a binder can not only effectively assemble nanomaterials and provide a stable mechanical structure, but also can further enhance the absorption loss of electromagnetic waves through the interface polarization effect between MXene and AgNWs, thereby effectively improving the electromagnetic wave absorption capacity of the wave absorption fabric.

[0061] Furthermore, it can be understood that for the two AgNWs / MXene-TPU@TPU composite fibers woven and staggered in the warp direction and the weft direction, a knot is formed at the weaving connection, which can be seen from Figure 1 the structure in the dashed box and Figure 2 It can be understood that the upper layer of the knot corresponds to Figure 1 the AgNWs / MXene-TPU core in the ellipse, the middle layer of the knot corresponds to Figure 1 the TPU shell layer of the ellipse and the rectangle, and the lower layer of the knot corresponds to Figure 1The AgNWs / MXene-TPU core in the rectangle, due to the conductivity of the AgNWs / MXene-TPU core and the insulation of the TPU shell, forms a junction capacitor at the junction, and the upper and lower electrodes are AgNWs / MXene-TPU, and the dielectric in the middle is TPU. The structure can be seen from Figure 2 The middle dashed box part is understood. With the junction capacitor, capacitive pressure sensing detection can be performed, and all the junction capacitors corresponding to the junctions can constitute a capacitive pressure sensor array.

[0062] Therefore, compared with the traditional flexible resistance sensing, on the basis of meeting the wave absorption performance, the AgNWs / MXene-TPU@TPU composite fiber proposed in the embodiment of the application is a capacitive sensing fiber structure. When external pressure acts, the upper and lower electrodes and the dielectric of the junction capacitor deform, the distance between the upper and lower electrodes changes, thereby the capacitance of the capacitive pressure sensor changes, and the detection of the pressure is completed. At the same time, the embodiment of the application connects the junction capacitors in series and in parallel on the plane, that is, in a certain AgNWs / MXene-TPU@TPU composite fiber weaving area, the junction capacitors are interconnected through the conductive AgNWs / MXene, thereby further forming a capacitive pressure sensor array. The capacitive pressure sensor array plane structure and circuit topology diagram are shown in Figure 3 It is calculated that the capacitance of the unit junction capacitor is about 0.2-0.6 pF, when stretched by 50%, the junction capacitor increases by about 150%, and the sensitivity is about 5.25 pF / MPa. The capacitive change is obvious. Therefore, compared with the original single capacitive sensing structure, this capacitive pressure sensor array can realize the pressure sensing of the entire plane and realize the stress distribution detection, and can expand the implementation range of the pressure sensing detection.

[0063] In an optional embodiment, the wave absorption frequency band of the elastic multifunctional wave absorption fabric based on the metamaterial structure covers 8-18 GHz, and the maximum reflection loss is-20 dB to-35 dB.

[0064] The range is obtained by simulation. Specifically, by changing the fiber diameters of the TPU fiber and the AgNWs / MXene-TPU@TPU composite fiber, and changing the thickness of the single-layer fabric formed, the number of fabrics, etc., the wave absorption peak of the obtained elastic multifunctional wave absorption fabric can be moved, so that the wave absorption frequency band covers 8-18 GHz, the maximum reflection loss is between-20 dB and-35 dB, and a wider wave absorption frequency band and higher absorption efficiency can be realized.

[0065] In an optional embodiment, when the preset pattern is a mouth-shaped pattern, in each mouth-shaped unit corresponding to the weaving area of the AgNWs / MXene-TPU@TPU composite fiber, the side length of the outer square is 3.0-18.0 mm, the side length of the inner square is 2.0-16.0 mm, and the distance between adjacent mouth-shaped units is the same and is 0.5-15.0 mm; and the thickness of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure is 1-5 mm.

[0066] In addition, on the basis of the above-mentioned embodiment, the preferred embodiment is that, in each mouth-shaped unit corresponding to the weaving area of the AgNWs / MXene-TPU@TPU composite fiber, the side length of the outer square is 5.5 mm, the side length of the inner square is 2.3 mm, the distance between adjacent mouth-shaped units is 1.0 mm, the thickness of each single-layer fabric is 1.5 mm, and the preset number of layers is two.

[0067] The wave-absorbing effect of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure obtained by the preferred embodiment can be seen from Figure 4 Figure 4 which is the absorption efficiency diagram of the mouth-shaped wave-absorbing fabric calculated by the finite element method in the embodiment of the present application. Figure 4 In the diagram, the horizontal axis represents frequency (Freq), and the vertical axis represents reflection loss (Reflection Loss). As can be seen, the wave-absorbing frequency range of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure includes 8.0-14.9 GHz, and the maximum reflection loss is -30.3 dB.

[0068] Specifically, Figure 4 In the diagram, the maximum reflection loss RL max is -30.3 dB, indicating that about 99.9% of electromagnetic waves can be absorbed. The wave-absorbing frequency is 8.0-14.9 GHz, which covers the entire X-band (about 8-12 GHz). The wave-absorbing frequency range, i.e., the waveband with a reflection loss RL less than -10 dB, is 6.9 GHz. As can be seen, the wave-absorbing efficiency of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure is high, and the wave-absorbing frequency range is wide.

[0069] In summary, the embodiment of the present application provides an elastic multifunctional wave-absorbing fabric based on a metamaterial structure, which can realize the functional integration of microwave absorption and pressure sensing, ensure the tensile properties and mechanical stability, further improve the air permeability and skin friendliness of the multifunctional wave-absorbing device, and is suitable for electromagnetic protection and pressure sensing applications in the field of wearable devices.

[0070] In a second aspect, the embodiment of the present application provides a preparation method of an elastic multifunctional wave-absorbing fabric based on a metamaterial structure, which is used to prepare the elastic multifunctional wave-absorbing fabric based on the metamaterial structure in the first aspect. Please refer to Figure 5 ​The method comprises the following steps:

[0071] S1, synthesizing an AgNWs dispersion liquid;

[0072] Embodiments of the present application can obtain an AgNWs dispersion liquid by using any existing method for synthesizing an AgNWs dispersion liquid, which is not specifically limited here.

[0073] In an optional embodiment, the synthesized AgNWs dispersion liquid can comprise:

[0074] Silver nitrate AgNO3 is used as a silver source, polyvinylpyrrolidone PVP is used as a coating agent, ethylene glycol EG is used as a solvent and reducing agent, sodium chloride NaCl and sodium bromide NaBr are used as nucleating agents, and silver nanowires AgNWs are synthesized by a polyol method at a certain temperature; and the synthesized AgNWs are filtered and dispersed to prepare an AgNWs dispersion liquid with a first concentration.

[0075] For the specific implementation process of the above-mentioned method, those skilled in the art can understand it in combination with related technologies, and detailed description is not given here.

[0076] The specific value of the first concentration can be set as needed, or multiple AgNWs dispersion liquids with different first concentrations can be prepared for use, which is reasonable.

[0077] In an optional embodiment, when synthesizing the AgNWs dispersion liquid, the certain temperature used can be 160℃-182℃.

[0078] In an optional embodiment, when synthesizing the AgNWs dispersion liquid, the mass ratio of silver ions Ag + to bromide ions Br - may be 20-60, and the mass ratio of silver ions Ag + to chloride ions Cl - may be 12-38.

[0079] S2, synthesizing an MXene dispersion liquid;

[0080] Embodiments of the present application can obtain an MXene dispersion liquid by using any existing method for synthesizing an MXene dispersion liquid, which is not specifically limited here.

[0081] In an optional embodiment, the synthesized MXene dispersion liquid comprises:

[0082] HCl / LiF is obtained as an etching liquid;

[0083] MAX phase Ti3AlC2 powder is added to the etching solution, and after sufficient etching, the precipitate is obtained by centrifugation, and the extracted precipitate is dispersed in water to prepare a MXene dispersion liquid of a second concentration.

[0084] HCl / LiF is obtained by mixing lithium fluoride LiF and hydrogen chloride (commonly known as hydrochloric acid) HCl solution in a certain proportion. For details, please refer to the relevant technical understanding, which will not be described in detail here.

[0085] MAX phase Ti3AlC2 and etching solution also have a certain proportion, and sufficient etching is usually a long etching time, which can be selected according to the empirical value.

[0086] For the specific implementation process of the above-mentioned manner, those skilled in the art can combine the relevant technical understanding, and will not be described in detail here.

[0087] Among them, the specific value of the second concentration can be set as needed, or a plurality of MXene dispersion liquids of different second concentrations can be configured for use, which is reasonable.

[0088] In an optional implementation, when synthesizing the MXene dispersion liquid, the ratio of HCl to LiF in the etching solution is 5ml:0.5g-25ml:2g. Among them, ml represents milliliter, and g represents gram.

[0089] In an optional implementation, when synthesizing the MXene dispersion liquid, the mesh number of Ti3AlC2 in the MAX phase Ti3AlC2 is 200-350.

[0090] In an optional implementation, when synthesizing the MXene dispersion liquid, the ratio of MAX phase Ti3AlC2 to etching solution is 1g:10mL-1g:20mL.

[0091] In an optional implementation, when synthesizing the MXene dispersion liquid, the sufficient etching time is 12h-36h. Among them, h represents hour.

[0092] S3, using the AgNWs dispersion liquid, the MXene dispersion liquid and TPU, preparing an AgNWs / MXene-TPU spinning liquid; and using TPU to prepare a TPU spinning liquid;

[0093] In an optional implementation, S3 can include the following steps:

[0094] S31, adding a TPU solution solvent to the MXene dispersion liquid, and adding the AgNWs dispersion liquid, stirring uniformly, then adding a certain mass of TPU particles, and stirring to obtain an AgNWs / MXene-TPU spinning liquid;

[0095] S32, a certain mass of TPU particles is added into the TPU solution solvent to be stirred and dissolved to obtain a TPU spinning solution.

[0096] In an optional embodiment, the TPU solution solvent can include at least one of N,N-dimethylformamide DMF, tetrahydrofuran THF, dimethyl sulfoxide DMSO and acetone.

[0097] In an optional embodiment, the concentration of the AgNWs dispersion liquid used in S3 can be 1 mg / ml-20 mg / ml; the concentration of the MXene dispersion liquid can be 2 mg / ml-25 mg / ml; when preparing the AgNWs / MXene-TPU spinning solution, the mass ratio of the AgNWs dispersion liquid and the MXene dispersion liquid added can be 1:1-1:10.

[0098] In an optional embodiment, the concentration of the AgNWs / MXene-TPU spinning solution can be 5 mg / ml-25 mg / ml.

[0099] In an optional embodiment, the mass of the TPU particles added in the AgNWs / MXene-TPU spinning solution and the TPU spinning solution is 3-15 g.

[0100] S4, the AgNWs / MXene-TPU spinning solution and the TPU spinning solution are respectively prepared into AgNWs / MXene-TPU as-spun fibers and TPU fibers by using a wet spinning process; and the AgNWs / MXene-TPU as-spun fibers are wrapped with a layer of TPU by using a dip coating process to form a coaxial structure, thereby obtaining AgNWs / MXene-TPU@TPU composite fibers.

[0101] In an optional embodiment, S4 can include the following steps:

[0102] S41, the AgNWs / MXene-TPU spinning solution and the TPU spinning solution are respectively added into needle tubes and pushed out through a spinning nozzle at a preset speed to form AgNWs / MXene-TPU as-spun fibers and TPU fibers in a coagulation bath.

[0103] S42, the AgNWs / MXene-TPU as-spun fibers are dipped in the TPU spinning solution for multiple times to wrap a layer of TPU on the outside to form a coaxial structure, thereby obtaining AgNWs / MXene-TPU@TPU composite fibers.

[0104] S4 is to obtain TPU fibers and AgNWs / MXene-TPU@TPU composite fibers by using a wet spinning process.

[0105] In an optional implementation, the diameter of the spinning nozzle can be 100-900 um; wherein um represents micrometers. In this way, the diameter of the TPU fiber and the AgNWs / MXene-TPU core body is 100-900 um.

[0106] In an optional implementation, the push-out speed of the AgNWs / MXene-TPU spinning solution or the TPU spinning solution, i.e., the preset speed, can be 100-1000 uL / min; wherein uL / min represents microliters per minute.

[0107] In an optional implementation, the solvent of the coagulation bath can include at least one of methanol, ethanol, and isopropanol.

[0108] In an optional implementation, the AgNWs / MXene-TPU as-spun fiber can be immersed in the TPU spinning solution for 1-5 times, and each time can be 1-60 seconds. In this way, the thickness of the TPU shell layer can be 100-250 um.

[0109] S5, according to the structure parameters obtained from the finite element simulation performed in advance, using the AgNWs / MXene-TPU@TPU composite fiber and the TPU fiber as raw materials, using a weaving machine to perform patterned weaving to obtain a single-layer fabric; and overlapping the same positions of a preset number of layers of single-layer fabrics up and down to obtain an elastic multifunctional wave-absorbing fabric based on a metamaterial structure; wherein the structure parameters represent the parameter information of the metamaterial structure corresponding to the single-layer fabric; the single-layer fabric includes a TPU fiber weaving area and a plurality of AgNWs / MXene-TPU@TPU composite fiber weaving areas arranged periodically and all being preset patterns.

[0110] In an optional implementation, the wave-absorbing frequency band of the elastic multifunctional wave-absorbing fabric based on a metamaterial structure covers 8-18 GHz, and the maximum reflection loss is -20 dB to -35 dB. For the obtaining method of the above parameter range, please refer to the related description of the first aspect.

[0111] In an optional implementation, the preset pattern includes:

[0112] a mouth-shaped pattern, a back-shaped pattern, a cross-shaped pattern, and a circular ring-shaped pattern.

[0113] In an optional implementation, the mouth-shaped pattern corresponds to the single-layer fabric of the elastic multifunctional wave-absorbing fabric based on a metamaterial structure, as shown in Figure 1 , and please refer to the related content of the first aspect for understanding.

[0114] In an optional embodiment, when the preset pattern is a mouth-shaped pattern, in each mouth-shaped unit corresponding to the weaving area of the AgNWs / MXene-TPU@TPU composite fiber, the side length of the outer square is 3.0-18.0 mm, the side length of the inner square is 2.0-16.0 mm, and the distance between adjacent mouth-shaped units is the same and is 0.5-15.0 mm; the thickness of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure is 1-5 mm.

[0115] In an optional embodiment, in each mouth-shaped unit corresponding to the weaving area of the AgNWs / MXene-TPU@TPU composite fiber, the side length of the outer square is 5.5 mm, the side length of the inner square is 2.3 mm, the distance between adjacent mouth-shaped units is 1.0 mm, the thickness of each single-layer fabric is 1.5 mm, and the preset number of layers is two.

[0116] For the preset pattern being a mouth-shaped pattern, when the above structure parameters are used, in an optional embodiment, the wave-absorbing frequency range of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure includes 8.0-14.9 GHz, and the maximum reflection loss is -30.3 dB. For the obtaining method of the above parameter range, see the related description of the first aspect.

[0117] The specific content of the above several optional embodiments can be seen from the related description of the first aspect, which will not be repeated here.

[0118] It should be noted that the optional embodiments in S1-S5 are only optional and can be selected alone or in combination, but these optional embodiments do not constitute a limitation on the embodiments of the present application.

[0119] The preparation method of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure provided in the embodiment of the application can prepare the elastic wave-absorbing fabric with high wave-absorbing efficiency and integrated pressure sensing function by using the wet spinning process and adopting the electromagnetic metamaterial structure. The elastic wave-absorbing fabric can not only complete the intended function of the device and endow the device with corresponding characteristics, but also reduce the number of elements of the flexible electronic system and reduce electromagnetic interference from the source. The macroscopic assembly of the MXene-AgNWs nanometer conductive material by using the wet spinning process in the embodiment of the application can form the elastic fiber with stable mechanical properties and stretchability, and can realize efficient wave-absorbing and pressure sensing. The addition of AgNWs can not only improve the stretchability of the conductive system, but also form an intercalation structure with MXene to avoid the agglomeration of the MXene nanometer material. Moreover, unlike the currently widely used resistance type sensor, the embodiment of the application proposes to use the junction capacitance between the fibers to form a capacitive pressure sensor array, which can detect slight deformation and fill the research gap of the wave-absorbing fabric with capacitive pressure sensing in the industry. For the related effects of the elastic multifunctional wave-absorbing fabric based on the metamaterial structure prepared in the embodiment of the application, please refer to the related content of the first aspect, which will not be repeated here.

[0120] A specific embodiment is given below to specifically illustrate the specific steps of the method of the embodiment of the application.

[0121] For S1, specifically, PVP solution is added to 12.1 L of EG, stirring is started, and the temperature is set to 30 DEG C and the stirring rate is set to 1105 rpm. Nitrogen is introduced, and the flow rate is set to 200 mL / min; AgNO3 solution is added, and 3 min later, NaBr solution and NaCl solution are added in sequence, and stirring is performed for 30 min.

[0122] The heating power of the mold temperature machine is set to 24 kW, the heating temperature is set to 170 DEG C, the solution temperature is raised to 170 DEG C by heating for 28 min, stirring is stopped, and the reaction is continued for 1 h; after the reaction is completed, the solution is cooled to room temperature and stored; the synthesized and filtered AgNWs are prepared into a solution with a concentration of 5 mg / ml for use. Wherein, rpm is the unit of rotation speed; mL / min represents milliliter per minute; kW represents kilowatt; mg / ml represents milligram per milliliter.

[0123] For S2, specifically, 2 g of LiF is dispersed in 5 mL of 10 mol / L HCl solution, stirred at 30°C for 15 min, then 1 g of MAX phase Ti3AlC2 is slowly added, and stirred at 35°C for 24 h to make it fully etched by Al; then the dispersion is centrifuged at 3500 rpm for 5 min each time, and the lower precipitate is taken until the pH value of the dispersion is 6; the precipitate is collected and dispersed in water, shaken uniformly, centrifuged at 3500 rpm for 15 min, and then the precipitate is taken and prepared into a 5 mg / ml MXene dispersion for use. Wherein, mol / L represents moles per liter.

[0124] For S3, specifically, DMF is added to the 5 mg / ml MXene dispersion, then 5 mg / ml AgNWs dispersion is added, and the mass ratio of the MXene dispersion and the AgNWs dispersion is 1:1. The mixture is stirred for 30 min to obtain an AgNWs / MXene dispersion; then 3 g of TPU is added and stirred at 70°C to obtain an AgNWs / MXene-TPU spinning solution, wherein the proportion of AgNWs / MXene in the system is 5%; and 5 g of TPU is added to DMF and stirred to dissolve to obtain a TPU spinning solution.

[0125] For S4, specifically, the AgNWs / MXene-TPU spinning solution is extruded at a speed of 200 uL / min through a spinning nozzle with a diameter of 800 um, and is formed into a primary fiber in a 10 wt% water / methanol solution coagulation bath to obtain an AgNWs / MXene-TPU primary fiber; then the AgNWs / MXene-TPU primary fiber is immersed in the TPU spinning solution for 3 times, each time for 30 s, and is dried to obtain an AgNWs / MXene-TPU@TPU composite fiber; and the TPU spinning solution is extruded at a speed of 600 uL / min through a spinning nozzle with a diameter of 800 um, and is formed into a TPU fiber in a 10 wt% water / methanol solution coagulation bath and is dried. Wherein, wt% is the unit of weight mass percentage, indicating the weight ratio and the proportion of a substance in a mixture.

[0126] For S5, specifically, according to the structure parameters obtained from the finite element simulation performed in advance, the AgNWs / MXene-TPU@TPU composite fiber and the TPU fiber are used as raw materials to perform patterned weaving by using a weaving machine to obtain a Figure 1The single-layer fabric of the shown mouth-shaped structure, wherein the structure parameters are: in each mouth-shaped unit, the outer square side length is 5.5 mm; the inner square side length is 2.3 mm; the spacing of adjacent mouth-shaped units is 1.0 mm; the thickness of each single-layer fabric is 1.5 mm; and according to the preset number of layers being two layers, the same positions of two single-layer fabrics are overlapped upward and downward, that is, the same position mouth-shaped units are aligned and overlapped upward and downward, to obtain the elastic multifunctional wave-absorbing fabric based on the metamaterial structure.

[0127] It can be seen that the elastic multifunctional wave-absorbing fabric based on the metamaterial structure is constructed by setting specific process parameters through the wet spinning process, has high wave-absorbing efficiency, good skin-friendly and breathable properties, excellent tensile properties, and can integrate a better pressure sensing function on a plane, and can be applied to wearable devices.

[0128] The above only describes preferred embodiments of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A flexible multi-functional wave-absorbing fabric based on a metamaterial structure, characterized in that, The elastic multifunctional wave-absorbing fabric based on the super material structure comprises: a preset number of single-layer fabrics stacked on the same position, each single-layer fabric comprising a TPU fiber woven area and a plurality of AgNWs / MXene-TPU@TPU composite fiber woven areas arranged periodically and in a preset pattern; wherein the TPU fiber woven area and the AgNWs / MXene-TPU@composite TPU fiber woven area are woven by a TPU fiber and an AgNWs / MXene-TPU@TPU composite fiber respectively by using a warp knitting machine; the TPU fiber and the AgNWs / MXene-TPU@TPU composite fiber are obtained based on a wet spinning process; the AgNWs / MXene-TPU@TPU composite fiber has a coaxial structure and comprises an AgNWs / MXene-TPU core and a TPU shell; different AgNWs / MXene-TPU@TPU composite fibers are subjected to capacitive pressure sensing detection by junction capacitances formed by an upper AgNWs / MXene-TPU as an upper electrode, a middle TPU as a dielectric and a lower AgNWs / MXene-TPU as a lower electrode at the woven connection in the warp and weft directions, and an array formed by the junction capacitances of all the woven connections forms a capacitive pressure sensor array; wherein the preparation process of the AgNWs / MXene-TPU@TPU composite fiber comprises: synthesizing an AgNWs dispersion liquid; synthesizing an MXene dispersion liquid; preparing an AgNWs / MXene-TPU spinning liquid by using the AgNWs dispersion liquid, the MXene dispersion liquid and TPU, and preparing a TPU spinning liquid by using TPU; obtaining an AgNWs / MXene-TPU as-spun fiber and a TPU fiber respectively by using a wet spinning process on the AgNWs / MXene-TPU spinning liquid and the TPU spinning liquid, and forming a coaxial structure by wrapping the AgNWs / MXene-TPU as-spun fiber with a layer of TPU by using a dip coating process to obtain an AgNWs / MXene-TPU@TPU composite fiber.

2. The elastic multi-functional metamaterial structure-based wave-absorbing fabric according to claim 1, characterized in that, The diameters of the TPU fiber and the AgNWs / MXene-TPU core are 100-900 um, and the thickness of the TPU shell is 100-250 um.

3. The elastic multi-functional wave-absorbing fabric based on metamaterial structure according to claim 1 or 2, characterized in that, The preset pattern comprises: a mouth-shaped pattern, a back-shaped pattern, a cross-shaped pattern and a circular ring-shaped pattern.

4. The elastic multi-functional metamaterial structure-based wave-absorbing fabric according to claim 1, characterized in that, The wave-absorbing frequency band of the elastic multifunctional wave-absorbing fabric based on the super material structure covers 8 GHz-18 GHz, and the maximum reflection loss is-20 dB--35 dB.

5. The elastic multi-functional metamaterial structure-based wave-absorbing fabric according to claim 3, characterized in that, When the preset pattern is a mouth-shaped pattern, in each mouth-shaped unit corresponding to each AgNWs / MXene-TPU@TPU composite fiber woven area, the outer square has a side length of 3.0-18.0 mm, the inner square has a side length of 2.0-16.0 mm, and the distance between adjacent mouth-shaped units is the same and is 0.5-15.0 mm; and the thickness of the elastic multifunctional wave-absorbing fabric based on the super material structure is 1 mm-5 mm.

6. A method for preparing an elastic multi-functional wave-absorbing fabric based on a metamaterial structure, characterized in that, The method for preparing the elastic multifunctional wave-absorbing fabric based on metamaterial structure according to any one of claims 1-5 comprises: Synthesizing an AgNWs dispersion liquid; Synthesizing an MXene dispersion liquid; Using the AgNWs dispersion liquid, the MXene dispersion liquid and TPU to prepare an AgNWs / MXene-TPU spinning liquid; and using TPU to prepare a TPU spinning liquid; Using the AgNWs / MXene-TPU spinning liquid and the TPU spinning liquid respectively to obtain AgNWs / MXene-TPU primary fibers and TPU fibers by using a wet spinning process; and using the AgNWs / MXene-TPU primary fibers to coat a layer of TPU outside by using a dip coating process to form a coaxial structure, thereby obtaining AgNWs / MXene-TPU@TPU composite fibers; Using the AgNWs / MXene-TPU@TPU composite fibers and the TPU fibers as raw materials to perform patterned weaving by using a weaving machine according to structure parameters obtained from a finite element simulation in advance, thereby obtaining a single-layer fabric; and stacking the same positions of a preset number of layers of single-layer fabrics one on top of another, thereby obtaining an elastic multifunctional wave-absorbing fabric based on metamaterial structure; wherein the structure parameters represent parameter information of a metamaterial structure corresponding to the single-layer fabric; and the single-layer fabric comprises a TPU fiber weaving area and a plurality of AgNWs / MXene-TPU@TPU composite fiber weaving areas arranged periodically and in a preset pattern.

7. The method of claim 6, wherein the method further comprises the step of: The method for synthesizing the AgNWs dispersion liquid comprises: Using silver nitrate AgNO3 as a silver source, polyvinylpyrrolidone PVP as a coating agent, ethylene glycol EG as a solvent and a reducing agent, sodium chloride NaCl and sodium bromide NaBr as nucleating agents, and synthesizing silver nanowires AgNWs by using a polyol method at a certain temperature; and after filtering and dispersing the synthesized AgNWs, an AgNWs dispersion liquid with a first concentration is prepared.

8. The method of claim 7, wherein the method further comprises the step of: The method for synthesizing the MXene dispersion liquid comprises: Obtaining HCl / LiF as an etching liquid; Adding MAX phase Ti3AlC2 powder to the etching liquid, centrifuging the precipitate after sufficient etching, dispersing the extracted precipitate in water, and preparing an MXene dispersion liquid with a second concentration.

9. The method of claim 8, wherein the method further comprises the step of: The method for preparing the AgNWs / MXene-TPU spinning liquid using the AgNWs dispersion liquid, the MXene dispersion liquid and TPU comprises: The method for preparing the TPU spinning liquid using TPU comprises: Adding a TPU solution solvent to the MXene dispersion liquid, adding the AgNWs dispersion liquid, stirring uniformly, adding a certain amount of TPU particles, and stirring and dissolving to obtain an AgNWs / MXene-TPU spinning liquid; Adding a certain amount of TPU particles to a TPU solution solvent, stirring and dissolving to obtain a TPU spinning liquid.

10. The method of claim 9, wherein the method further comprises the step of: The AgNWs / MXene-TPU spinning solution and the TPU spinning solution are respectively prepared by using a wet spinning process, so as to obtain AgNWs / MXene-TPU as-spun fibers and TPU fibers; and the AgNWs / MXene-TPU as-spun fibers are coated with a layer of TPU by using a dip coating process to form a coaxial structure, so as to obtain AgNWs / MXene-TPU@TPU composite fibers, including: ​ The AgNWs / MXene-TPU spinning solution and the TPU spinning solution are respectively added into needle tubes and pushed out through a spinning nozzle at respective preset speeds, and are shaped into AgNWs / MXene-TPU as-spun fibers and TPU fibers through a coagulation bath; The AgNWs / MXene-TPU as-spun fibers are dip coated in the TPU spinning solution for multiple times, so as to coat the outside of the AgNWs / MXene-TPU as-spun fibers with a layer of TPU to form a coaxial structure, thereby obtaining AgNWs / MXene-TPU@TPU composite fibers.

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