A preparation method of an ultra-wideband terahertz composite fabric based on Ti 3 C 2 T x materials

Abstract

The present invention belongs to the field of terahertz absorbing materials, and specifically provides a preparation method of an ultra-wideband terahertz composite fabric based on Ti3C2T x materials, aiming to solve the problems existing in terahertz absorbing materials, such as narrow absorption bandwidth, large thickness and poor practicability. The present invention prepares a Ti3C2T x composite fabric with strong electromagnetic absorption and ultra-wideband through a simple and reliable process route. A suede cloth with rich fiber microstructures on the surface is used, and Ti3C2T x nanosheets are attached to the suede cloth by the dipping method. When the concentration of the Ti3C2T x dispersion is 1.0 - 3.0 mg / ml, the absorption efficiency of the Ti3C2T x composite fabric can reach 100% in the range of 0.3 - 1.2 THz; moreover, the reflection loss of the Ti3C2T x composite fabric still remains at about -10 dB in the low-frequency part of 20 - 300 GHz, and the lowest reflection loss is -34.8 dB at 79.2 GHz; in addition, after the Ti3C2T x composite fabric has undergone 500 times of bending and folding, the reflection loss is still below -30 dB, and the change in conductivity before and after is small.

Description

Technical Field

[0001] The present invention belongs to the field of terahertz absorbing materials and specifically provides a Ti-based 3 C 2 T x Preparation method of ultra-wideband terahertz composite fabric of material. Background Art

[0002] Terahertz waves (0.1-10THz) are between microwaves and infrared rays, and have many unique properties, such as good optical resolution, strong penetration and wide spectrum. At present, the research on terahertz technology is mainly focused on terahertz radiation, terahertz detection, terahertz communication and terahertz imaging. However, with the rapid development of various digital and high-frequency electronic and electrical equipment, a large amount of terahertz waves are radiated into space during operation, which leads to the emergence of problems such as terahertz electromagnetic interference (EMI). EMI not only affects the normal operation of electronic equipment, but also harms human health and the environment. Terahertz absorbing materials can convert incident electromagnetic waves into heat or other forms of energy for dissipation, thereby reducing the harm of electromagnetic radiation. They are used to reduce or prevent electromagnetic interference between electrical equipment, reduce electromagnetic pollution, protect the ecological environment and human health, and can also be used as equipment stealth materials. It can be seen that terahertz absorbing materials are the key guarantee for promoting the application of terahertz technology. Cheap, broadband, efficient and environmentally tolerant terahertz absorbing materials have become one of the main goals of terahertz technology research.

[0003] At present, researchers have designed a variety of terahertz absorbing materials with high electromagnetic shielding efficiency, but the loss mechanism of most terahertz absorbing materials is based on the conductivity loss of the material itself. Such absorbing materials will produce a large amount of reflected electromagnetic waves, causing secondary pollution; and traditional electromagnetic interference shielding materials such as metals and metal composites have problems such as high density, poor corrosion resistance, and high cost, and have limitations in environmental adaptability, portability, and tailorability. 3 C 2 T x The material refers to a two-dimensional layered material composed of transition metal carbides, which has a high specific surface area and rich polar functional groups, and provides a large number of dipole loss centers, making it considered to be an excellent terahertz absorber. For example, Wan et al. proposed a Ti based on copolymer-polyacrylic acid emulsion (PAL) 3 C 2 T xWater-based coating (Wan H, Liu N, Tang J, et al. ACS nano, 2021, 15(8): 13646-13652.), EMI SE on quartz reached 64.9dB, and reflection loss of -32.8dB was obtained on sponge foam; Li et al. reported an ultrathin broadband Ti 3 C 2 T x / rGO composite film (Li S, Xu S, Pan K, et al. Carbon, 2022, 194: 127-139.), which exhibits an excellent shielding effectiveness of 54.2dB, with a maximum reflection loss value of -57.7dB, and an effective absorption bandwidth covering 0.37~2.0THz; however, carbon-based materials are too fragile, easily oxidized, and have poor environmental tolerance, making it difficult to meet the needs of various environmental applications.

[0004] Using fiber microstructure as the skeleton of terahertz absorbing material can not only obtain good impedance matching characteristics, but also has the function of carrying absorbing material, so that more electromagnetic waves can enter the interior of the material and be absorbed; and the absorbing shielding fabric has the advantages of being relatively light, easy to bend, can be cut at will, non-toxic and environmentally friendly, and has broad application prospects in life and special fields; however, there is currently little research on absorbing shielding fabrics, and there are problems such as narrow absorption bandwidth and large thickness, which limit the scope of its practical application; therefore, the present invention is based on Ti 3 C 2 T x The conductivity loss and ohmic loss of the material are combined with the fiber microstructure in the suede cloth. A Ti-based 3 C 2 T x The ultra-wideband terahertz composite fabric of the material is used to achieve ultra-wideband absorption and shielding in the terahertz frequency band. Summary of the invention

[0005] The purpose of the present invention is to address the shortcomings of terahertz absorption materials such as narrow absorption bandwidth, large thickness and poor practicality, and to propose a Ti-based 3 C 2 T x The preparation method of ultra-wideband terahertz composite fabric of the material is to prepare Ti with strong electromagnetic absorption and ultra-wideband through a simple and reliable process route. 3 C 2 T x The composite fabric is a suede fabric with rich fiber microstructure on the surface. Ti 3 C 2 T x Nanosheets are attached to suede cloth. 3 C2 T x When the dispersion concentration ranges from 1 to 3.0 mg / ml, Ti 3 C 2 T x The absorption efficiency of the composite fabric in the range of 0.3 to 1.2 THz can reach 100%; and 3 C 2 T x The reflection loss of the composite fabric in the low-frequency part of 20 to 300 GHz remains at about -10 dB, and the lowest reflection loss is -34.8 dB at 79.2 GHz. 3 C 2 T x After the composite fabric was bent and folded 500 times, the reflection loss was still below -30dB, and the conductivity changed little before and after.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A Ti-based 3 C 2 T x The method for preparing an ultra-wideband terahertz composite fabric of a material is characterized by comprising the following steps:

[0008] Step 1: Pretreatment of suede cloth;

[0009] Fluffy cloth (FC) is used as Ti 3 C 2 T x As the carrier of the nanosheets, the suede cloth needs to be cut into a preset shape and cleaned for use in advance;

[0010] Step 2: Ti 3 C 2 T x Synthesis of (MXene) dispersions;

[0011] A mixture of hydrofluoric acid (HF) and hydrochloric acid (HCl) was used to treat Ti 3 AlC 2 Selective etching is performed to synthesize Ti 3 C 2 T x Dispersion, Ti 3 C 2 T x The concentration of the dispersion is 1 to 3.0 mg / ml;

[0012] Step 3: Ti 3 C 2 T x Preparation of composite fabrics;

[0013] Ti 3 C 2 T x The dispersion liquid is used as the soaking liquid, and the suede cloth is soaked by the soaking method, and the ultra-wideband terahertz composite fabric is obtained after drying.

[0014] Furthermore, in step 1, the suede cloth is cleaned by using ethanol and deionized water in sequence, and then drying for standby use.

[0015] Furthermore, the specific process of step 2 is:

[0016] First, 2-4 mL HF, 12-24 mL HCl, and 6-12 mL deionized (DI) water are mixed to obtain a mixed acid solution;

[0017] Then, 1-2 g Ti 3 AlC 2 The powder was slowly added to the mixed solution and stirred in a constant temperature water bath at 450 rpm for 24 h at 35 °C for selective etching. After etching, the solution was centrifuged at 8000 rpm for 10 min and washed with DI water until pH>6 to obtain a multilayer Ti 3 C 2 T x Sediment;

[0018] Then, the obtained multilayer Ti 3 C 2 T x The precipitate was mixed with 1-2 g LiCl in 50-100 mL DI water and stirred in a constant temperature water bath at 450 rpm at 35 °C for 4 h, then centrifuged at 3500 rpm for 10 min and washed with DI water to swell the precipitate to obtain a monolayer Ti 3 C 2 T x Sediment;

[0019] Finally, the single layer Ti 3 C 2 T x The precipitate was dispersed in DI water and centrifuged at 7500 rpm for 8 min to obtain a uniformly dispersed Ti 3 C 2 T x Dispersion.

[0020] Furthermore, the specific process of step 3 is as follows:

[0021] First, Ti 3 C 2 Tx The dispersion was placed in a magnetic stirring water bath, the speed was set to 600-800 rpm, the water bath temperature was set to 30°C and stirred for 1 h (to avoid agglomeration);

[0022] Then, the stirred Ti 3 C 2 T x Pour the dispersion into the soaking container, the water level should be 2-4mm higher than the thickness of the suede cloth, and then spread the suede cloth and soak it in Ti 3 C 2 T x In the dispersion, use a roller to roll the suede cloth back and forth 5 to 8 times;

[0023] Finally, the suede cloth was taken out and placed on a dry glass plate to dry for 24 h to obtain an ultra-wideband terahertz composite fabric (Ti 3 C 2 T x composite fabric).

[0024] Based on the above technical solution, the beneficial effects of the present invention are:

[0025] The present invention provides a Ti-based 3 C 2 T x The preparation method of ultra-wideband terahertz composite fabric of the material is simple and reliable. The Ti 3 C 2 T x Nanosheets attached to suede cloth to form Ti 3 C 2 T x Composite fabric, Ti 3 C 2 T x The fiber surface of the composite fabric forms a rich Ti 3 C 2 T x Membrane structure, good impedance matching based on fiber surface and Ti 3 C 2 T x The conductivity loss and ohmic loss of the nanosheets achieve ultra-wideband absorption in the range of 0.3 to 1.2 THz. 3 C 2 T x Ti concentration of 1-3.0 mg / ml 3 C 2 T xThe absorption efficiency of the composite fabric can reach 100%; and its reflection loss in the low-frequency part of 20 to 300 GHz is still maintained at about -10dB, and the lowest reflection loss is -34.8dB at 79.2GHz. 3 C 2 T x The composite fabric has excellent bending strain capacity. After 500 times of bending and folding, its reflection loss is still below -30dB, and the conductivity changes little before and after. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 In the embodiment of the present invention, based on Ti 3 C 2 T x Schematic diagram of the process for preparing ultra-wideband terahertz composite fabrics of materials.

[0027] Figure 2 Ti in the embodiment of the present invention 3 C 2 T x Microstructure diagram of the material, where (a) is a single layer of Ti 3 C 2 T x SEM image of nanosheets, (b) Ti 3 C 2 T x HRTEM image of a single layer, (c) is Ti 3 AlC 2 -MAX phase and Ti 3 C 2 T x XRD patterns of the films.

[0028] Figure 3 In the embodiment of the present invention, based on Ti 3 C 2 T x Optical image and surface SEM image of the ultra-wideband terahertz composite fabric of the material, where (a) is the optical image and (b) is the surface SEM characterization image.

[0029] Figure 4 Graph showing the reflection efficiency of multiple fabric materials in the range of 0.3 to 1.2 THz in an embodiment of the present invention (ML: cotton, FC: suede).

[0030] Figure 5 Graph showing transmission efficiency of multiple fabric materials in the range of 0.3 to 1.2 THz in an embodiment of the present invention (ML: cotton, FC: suede).

[0031] Figure 6FIG. 1 is a graph showing the absorption efficiency of multiple fabric materials in the range of 0.3 to 1.2 THz in an embodiment of the present invention (ML: cotton, FC: suede).

[0032] Figure 7 In the embodiment of the present invention, based on Ti 3 C 2 T x Schematic diagram of the electromagnetic absorption loss mechanism of the ultra-wideband terahertz composite fabric of the material.

[0033] Figure 8 The Ti concentrations in the embodiments of the present invention are 3 C 2 T x The results of the absorption performance of ultra-wideband terahertz composite fabrics under dispersion liquid, where (a) is the terahertz reflection time-domain spectrum and (b) is the terahertz transmission time-domain spectrum.

[0034] Fig. 9 The Ti concentrations in the embodiments of the present invention are 3 C 2 T x Reflection efficiency diagram of ultra-wideband terahertz composite fabric in the range of 0.2 to 1.2 THz under dispersion liquid.

[0035] Fig.10 The Ti concentrations in the embodiments of the present invention are 3 C 2 T x Transmission efficiency diagram of ultra-wideband terahertz composite fabric in the range of 0.2 to 1.2 THz under dispersion liquid.

[0036] Fig.11 This is a time-domain spectrum diagram of terahertz reflection of the ultra-wideband terahertz composite fabric in the range of 0.2 to 1.2 THz at multiple incident angles in an embodiment of the present invention.

[0037] Fig.12 In the embodiment of the present invention, based on Ti 3 C 2 T x The reflection loss results of the ultra-wideband terahertz composite fabric of the material under the incident electromagnetic waves of 20 to 300 GHz.

[0038] Fig.13 In the embodiment of the present invention, based on Ti 3 C 2 T x A graph showing how the surface resistance of the material's ultra-wideband terahertz composite fabric changes with bending and twisting.

[0039] Fig.14 In the embodiment of the present invention, based on Ti 3 C 2 Tx The reflection loss results of the ultra-wideband terahertz composite fabric of the material before and after bending and twisting 500 times, where (a) is the reflection loss result before and after bending 500 times, and (b) is the reflection loss result before and after twisting 500 times. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0041] This embodiment provides a method based on Ti 3 C 2 T x Ultra-broadband terahertz composite fabric of materials (hereinafter referred to as Ti 3 C 2 T x The preparation method of composite fabric) is as follows: Figure 1 As shown, the following steps are included:

[0042] Step 1: Pretreatment of suede cloth;

[0043] Fluffy cloth (FC) is mainly composed of polyester fiber, which has the advantages of environmental protection, comfort and durability. First, the FC is cut into squares of 10×10 cm. Then, it is washed with anhydrous ethanol and deionized water in turn. Finally, it is dried for standby use.

[0044] Step 2: Ti 3 C 2 T x Synthesis of (MXene) dispersions;

[0045] Ti was treated with a mixture of hydrofluoric acid (HF) and hydrochloric acid (HCl). 3 AlC 2 (MAX phase) selective etching, synthesis of Ti 3 C 2 T x Dispersion liquid;

[0046] First, 2-4 mL HF, 12-24 mL HCl, and 6-12 mL deionized (DI) water were mixed; then, 1-2 g Ti 3 AlC 2 The powder was slowly added to the solution and stirred at 35 °C for 24 h for selective etching. After etching, the solution was centrifuged at 8000 rpm for 10 min and washed with DI water until pH>6 to obtain a multilayer Ti 3 C 2 T xprecipitate; then, the obtained precipitate was mixed with 1-2 g LiCl in 50-100 mL DI water and stirred for 4 hours, and then centrifuged at 3500 rpm for 10 min using a centrifuge, and washed with DI water to swell the precipitate to obtain a single layer of Ti 3 C 2 T x Finally, the expanded precipitate was dispersed in DI water and centrifuged at 7500 rpm for 8 min to obtain a uniformly dispersed Ti 3 C 2 T x Dispersion liquid;

[0047] Step 3: Ti 3 C 2 T x Preparation of composite fabrics;

[0048] First, the prepared Ti 3 C 2 T x The dispersion was placed in a magnetic stirring water bath, the speed was set to 600 rpm, the water bath temperature was set to 30 °C and stirred for 1 h (to avoid agglomeration); then, the stirred Ti 3 C 2 T x Pour the dispersion into the culture dish, with the horizontal surface height 2 to 4 mm higher than the thickness of the suede cloth to ensure uniform dispersion; then spread the suede cloth and soak it in Ti 3 C 2 T x In the dispersion, use a roller to roll the suede cloth back and forth 5 to 8 times to 3 C 2 T x The dispersion was squeezed into the suede cloth; finally, the suede cloth was taken out with tweezers and placed on a dry glass plate to dry for 24 hours to obtain Ti 3 C 2 T x Composite fabric.

[0049] Therefore, in this embodiment, Ti having a large number of functional groups on the surface is immersed 3 C 2 T x Dispersions (-OH, -F and -Cl, etc.) can make Ti 3 C 2 T x The nanosheets are effectively adsorbed on the flannel fibers, which is conducive to the formation of many Ti 3 C 2 T x film, thereby achieving high electromagnetic shielding absorption effect.

[0050] The following describes the Ti-based 3 C 2 T x Microstructure of ultra-wideband terahertz composite fabrics of materials;

[0051] like Figure 2 (a) shows the prepared single-layer Ti 3 C 2 T x Scanning electron microscope (SEM) image of the nanosheets shows the prepared Ti 3 C 2 T x The lateral size of the nanosheet is 1.96 μm; further, Figure 2 (b) shows Ti 3 C 2 T x High-resolution transmission electron microscopy (HRTEM) images of nanosheets show that Ti 3 C 2 T x The nanosheets are very thin and transparent, with a thickness of about 0.26nm; Figure 2 (c) shows Ti 3 AlC 2 (MAX phase) and Ti 3 C 2 T x From the XRD pattern, it can be seen that after etching, the original Ti 3 AlC 2 The characteristic peak (39.2°) of Ti 3 C 2 T x The characteristic peak (8.3°) of Ti 3 AlC 2 Already converted to Ti 3 C 2 T x ;

[0052] like Figure 3 (a) shows Ti 3 C 2 T x Optical image of the composite fabric showing the prepared Ti 3 C 2 T x The composite fabric has light flexibility and large specific surface area; Figure 3(b) shows Ti 3 C 2 T x Surface SEM characterization image of the composite fabric. Under the driving force of van der Waals force and hydrogen bond, Ti 3 C 2 T x The material is firmly adsorbed on the fiber surface of the suede cloth, bridging and connecting with adjacent fibers, and forming a rich Ti 3 C 2 T x The membrane structure improves the absorption loss characteristics of the fabric through multiple reflection attenuation inside the material.

[0053] The following is an explanation of the working principle of the Ti-based 3 C 2 T x The electromagnetic absorption characteristics and intrinsic mechanism of ultra-wideband terahertz composite fabrics of materials;

[0054] When electromagnetic waves are incident on the surface of an object, reflected waves usually occur due to the impedance discontinuity of the surface, and the absorbing material has the ability to absorb and lose electromagnetic waves. Therefore, if it is assumed that the total energy of the incident electromagnetic waves is 1, the reflected power R(ω), transmitted power T(ω), and absorbed power A(ω) of the absorbing material will have the following relationship:

[0055] T(ω)+R(ω)+A(ω)=1

[0056] Among them, the power coefficients of R(ω), T(ω), and A(ω) can be calculated by the scattering parameter S 11 , S 12 , S 21 , S 22 The calculation method is as follows:

[0057] R=|S 11 | 2 =|S 22 | 2

[0058] T=|S 21 | 2 =|S 12 | 2

[0059] According to the above formula, if we want to improve the absorbing performance and shielding efficiency of electromagnetic absorbing materials, we must try to reduce the transmission coefficient and reflection coefficient of the material. For absorbing materials, achieving broadband strong absorption generally requires the following two conditions to be met at the same time: 1) good impedance matching characteristics, 2) strong intrinsic loss. First, in order to achieve the minimum surface reflection power, it is necessary to ensure that the electromagnetic wave can enter the absorber as much as possible. According to the principle of electromagnetic wave propagation, the material reflection impedance matching and vertical incidence expressions can be derived as follows:

[0060] R=(ZZ 0 ) / (Z+Z 0 )

[0061]

[0062]

[0063] Where R is the reflection coefficient, Z is the wave impedance at the material interface, and Z 0 ≈377Ω is the free space impedance, E and H are the electric field strength and magnetic field strength respectively, μ r and μ 0 Represent the relative magnetic permeability of the absorbing material and the magnetic permeability of vacuum, ε r and ε 0 represent the relative dielectric constant of the absorbing material and the dielectric constant of vacuum respectively; therefore, in order to minimize the reflection of electromagnetic waves, it is necessary to ensure that Z and Z 0 To maximize the match, that is, μ r ≈ε r ; For electromagnetic waves incident on the surface of the absorbing material, the reflection loss (RL) can be calculated by transmission line theory, which can be obtained by the following formula:

[0064]

[0065] It can be seen that the reflection of electromagnetic waves on the surface of the material is closely related to the impedance of the material surface. At the same time, electromagnetic absorption and reflection losses are also affected by the dielectric constant and magnetic permeability of the absorbing material.

[0066] For Ti 3 C 2 T x Electromagnetic absorption performance of composite fabrics, Ti 3 C 2 T x The electromagnetic absorption performance of the composite fabric in the range of 0.3 to 1.2 THz was carefully studied, revealing its absorption mechanism and testing its bending strain capacity. Fiber suede is a natural insulating material. The original textile is almost completely transparent to the incident terahertz wave and has no reflection, such as Figure 4 and 5 As shown; and compared with muslin (ML), the transmission of fluffy cloth (FC) is stronger, that is, the impedance matching performance of fluffy cloth is better. 3 C 2 T x The transmission efficiency of electromagnetic waves in the terahertz frequency band of the two textiles soaked in Ti dispersion is close to 0, while the reflection efficiency of cotton textiles increases, which will cause secondary pollution caused by reflected electromagnetic waves; therefore, the method of soaking Ti 3 C 2 T x The suede cloth with dispersion liquid can not only shield the penetration of electromagnetic waves, but also reduce reflection and increase electromagnetic shielding efficiency. Figure 6 As shown, Ti 3 C 2 @ML's absorption efficiency is significantly reduced in the low-frequency part. This is because the cotton product has less fiber content inside, and the impedance does not match the free space at low frequencies, resulting in a large amount of electromagnetic reflection; while Ti 3 C 2 @FC fabric has greatly improved electromagnetic absorption performance, and the electromagnetic absorption efficiency is close to 100%, proving that the use of flannel fiber microstructure as Ti 3 C 2 T x The skeleton can obtain good impedance matching characteristics, which can allow more electromagnetic waves to enter the interior of the material and be absorbed; it can be seen that a large amount of Ti is formed on the surface of the suede fiber. 3 C 2 T x The incident electromagnetic wave undergoes a process of "absorption-reflection-reabsorption" in the velvet.

[0067] like Figure 7 The Ti in this embodiment is shown 3 C 2 T x Absorption loss mechanism of composite fabrics, Ti 3 C 2 T x The absorption and attenuation ability of the nanosheet to the incident electromagnetic wave mainly depends on the conductivity loss and ohmic loss, which are respectively composed of Ti 3 C 2 T x The high conductivity and dielectric properties of Ti 3 C 2 T x The rich interface contact between Ti and velvet fibers can be considered as a polarized capacitor structure, which absorbs the incident electromagnetic wave through conduction loss. 3 C 2 Tx The nanosheet has a lateral structure. When electromagnetic waves are incident into the layer, the carriers are emitted and migrated, forming a microcurrent, generating ohmic losses and consuming the incident electromagnetic energy. In addition, the velvet fiber surface is rich in Ti 3 C 2 T x membrane, which will trigger the Ti 3 C 2 T x Multiple reflections of the incident electromagnetic waves between layers extend the path of the electromagnetic waves, generate more interface polarization, increase the internal ohmic loss and dielectric loss, and further enhance the electromagnetic wave absorption and attenuation capability.

[0068] Furthermore, by changing the immersion Ti 3 C 2 T x The concentration of the dispersion is compared in this example. 3 C 2 T x The effect of concentration on electromagnetic absorption attenuation, such as Figure 8 As shown in the figure, as Ti 3 C 2 T x As the concentration increases, the electric field intensity in the terahertz transmission time-domain spectrum gradually decreases, and the reflection spectrum intensity is almost 0. Fig. 9 and Fig.10 As shown, we can further see that Ti 3 C 2 T x The effect of concentration on the reflection and transmission efficiency of suede cloth; As can be seen from the figure, Ti 3 C 2 T x With the increase of Ti concentration, the transmission efficiency of electromagnetic waves in the 0.3-1.2 THz frequency band continues to decrease. 3 C 2 T x When the concentration reaches 1.5mg / ml, Ti 3 C 2 T x The composite fabric can achieve transmission and reflection close to 0, that is, the absorption efficiency is close to 100%. 3 C 2 T x The concentration of Ti will lead to excessive conductivity inside the textile, causing enhanced low-frequency reflection. 3 C 2 T x The interaction between Ti and the velvet fibers produces more interfacial polarization. 3 C 2 T xThe conductivity loss caused by nanosheets increases, so high concentrations of Ti 3 C 2 T x The composite fabric has a lower reflectivity. Furthermore, for 1.5 mg / ml Ti 3 C 2 T x Composite fabric, this embodiment compares the impact of the incident angle of electromagnetic waves on its reflection efficiency, such as Fig.11 As shown, as the incident angle increases, the reflection efficiency remains almost unchanged.

[0069] Furthermore, the present invention tested 1 mm thick Ti 3 C 2 T x The reflection loss of composite fabrics under incident electromagnetic waves of 20 to 300 GHz, such as Fig.12 As shown in the figure, it can be seen that the reflection loss of the low-frequency part is still maintained at about -10dB, and the lowest reflection loss is -34.8dB at 79.2GHz, which confirms that Ti 3 C 2 T x The composite fabric also has good absorption performance at lower frequencies and even in the millimeter wave band. 3 C 2 T x Mechanical durability of composite fabrics. This example characterizes the 3 C 2 T x The relationship between the surface resistance of the composite fabric and bending and twisting, such as Fig.13 As shown in the figure, after 200 bending and twisting cycles, the surface resistance increases slightly and changes slightly, such as Fig.13 As shown in (a); after 300 bending and twisting, Ti 3 C 2 T x The surface resistance of the composite fabric gradually increased from 20.2±4.2Ω / □ at the beginning to 37.1±6.4Ω / □ and 41.2±8.2Ω / □. The stable surface resistance is due to the flannel fiber and Ti 3 C 2 T x Due to the strong interaction between the fibers, the fiber composite fabric plays a certain protective role. Furthermore, since the conductivity has a certain influence on the absorption attenuation, this example also compares the Ti 3 C 2 T x The reflection loss of the composite fabric before and after bending and twisting 500 times, such as Fig.14 As shown, it can be seen that Ti 3 C2 T x The reflection loss of the composite fabric changes little before and after the cycle, and the reflection loss is still below -30dB, and the conductivity does not change much before and after, which means that the absorption material Ti inside the composite fabric 3 C 2 T x It is still adsorbed on the fiber surface, has strong anti-bending properties, and plays a role in stable absorption.

[0070] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A Ti3C2T based x The method for preparing an ultra-wideband terahertz composite fabric of a material is characterized in that: The following steps are involved: Step 1: Pretreatment of suede cloth; A suede cloth is used as a carrier, specifically a fiber suede cloth, and the suede cloth is cut into a preset shape and washed for later use; Step 2: Ti3C2T x Synthesis of dispersions; Ti3AlC2 was selectively etched using a mixture of hydrofluoric acid and hydrochloric acid to synthesize Ti3C2T x Dispersion, Ti3C2T x The concentration of the dispersion is 1 to 3.0 mg / ml; Step 3: Ti3C2T x Preparation of composite fabrics; Ti3C2T x The dispersion liquid is used as the soaking liquid, and the suede cloth is soaked by the soaking method, and the ultra-wideband terahertz composite fabric is obtained after drying; the specific process is: First, Ti3C2T x The dispersion was placed in a magnetic stirring water bath, the speed was set to 600-800 rpm, the water bath temperature was set to 30°C and stirred for 1 h; Then, the stirred Ti3C2T x Pour the dispersion into the soaking container, the water level should be 2-4 mm higher than the thickness of the suede cloth, and then spread the suede cloth and soak it in the Ti3C2T x In the dispersion, use a roller to roll the suede cloth back and forth 5 to 8 times; Finally, the suede cloth was taken out and placed on a dry glass plate to dry for 24 hours to obtain an ultra-wideband terahertz composite fabric. Ti3C2T x Membrane structure.

2. The Ti3C2T based on claim 1 x The method for preparing an ultra-wideband terahertz composite fabric of a material is characterized in that: In step 1, the suede cloth is cleaned by using ethanol and deionized water in sequence, and then drying for standby use.

3. The Ti3C2T based on claim 1 x The method for preparing an ultra-wideband terahertz composite fabric of a material is characterized in that: The specific process of step 2 is: First, 2-4 mL HF, 12-24 mL HCl, and 6-12 mL deionized water are mixed to obtain a mixed acid solution; Then, 1-2 g of Ti3AlC2 powder was slowly added to the mixed solution and stirred in a constant temperature water bath at 450 rpm at 35 °C for 24 h for selective etching; After etching, the samples were centrifuged at 8000 rpm for 10 min and washed with DI water until pH>6 to obtain multilayer Ti3C2T x Sediment; Then, multilayer Ti3C2T x The precipitate was mixed with 1-2 g LiCl in 50-100 mL DI water and stirred in a constant temperature water bath at 35 °C at 450 rpm for 4 h. The mixture was then centrifuged at 3500 rpm for 10 min and washed with DI water to obtain a single layer of Ti3C2T x Sediment; Finally, the single layer Ti3C2T x The precipitate was dispersed in DI water and centrifuged at 7500 rpm for 8 min to obtain uniformly dispersed Ti3C2T x Dispersion.

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