A T-ZnO@PANI / Ti3C2T x Electromagnetic shielding material, method of making and use thereof

Abstract

The application relates to the technical field of flexible electromagnetic shielding materials, in particular to a T-ZnO@PANI / Ti3C2T x An electromagnetic shielding material, a preparation method and application thereof. The preparation method of the electromagnetic shielding material comprises the following steps: adding Ti3C2T x The electromagnetic shielding material prepared by the method has the characteristics of wide-frequency strong absorption, low filler loading, high mechanical flexibility and no secondary pollution, and can be used as a flexible electromagnetic shielding material.

Description

Technical Field

[0001] This invention relates to the field of flexible electromagnetic shielding materials, specifically to a T-ZnO@PANI / Ti3C2T x Electromagnetic shielding materials, their preparation methods, and applications. Background Technology

[0002] With the rapid popularization of 5G, the Internet of Things (IoT), and smart terminal devices, the scale and frequency of information interaction between electronic devices have increased significantly, and human society's dependence on the electromagnetic environment has continued to rise. However, the booming development of electromagnetic wave technology has also brought about an increasingly serious problem of electromagnetic radiation pollution. Electromagnetic radiation has been recognized as the "fourth largest source of pollution" after water pollution, air pollution, and noise pollution. It not only causes electromagnetic interference to the normal operation of electronic devices, threatening the safety of aerospace, precision medicine, and other fields, but may also pose potential hazards to human health through thermal effects, non-thermal effects, and cumulative effects. Therefore, developing new electromagnetic protection materials that combine high-efficiency electromagnetic protection capabilities, lightweight, high flexibility, and environmental friendliness has become a key issue that urgently needs to be addressed.

[0003] Two-dimensional transition metal carbides MXene (in the form of Ti3C2T) x With its excellent metal-like conductivity, abundant surface functional groups, and unique layered structure, MXene has shown great application potential in the field of electromagnetic protection. However, single MXene materials still face many bottlenecks in practical applications: on the one hand, its excessively high conductivity easily leads to impedance mismatch, causing a large number of electromagnetic waves to be reflected on the material surface, making it difficult to penetrate into the interior for effective absorption; on the other hand, the van der Waals forces between MXene nanosheets make them prone to self-stacking, significantly reducing the effective specific surface area and active sites, thus limiting the full utilization of loss capacity; in addition, a single loss mechanism is difficult to meet the requirements of broadband and high-efficiency wave absorption.

[0004] To address these issues, researchers have attempted to optimize impedance matching and construct heterojunctions to enhance polarization loss by introducing dielectric materials or magnetic components. However, existing strategies largely rely on component superposition and structural optimization, and the regulation of charge behavior at the interface remains in a passive response state, making it difficult to achieve a leap from "passive polarization" to "actively induced polarization."

[0005] In recent years, the introduction of built-in electric field theory has provided new insights into heterogeneous interface engineering: when materials with different work functions are in close contact, electrons spontaneously migrate in a directional manner, forming a space charge region, i.e., a built-in electric field, at the interface. This can induce strong interfacial polarization relaxation under alternating electromagnetic fields, thereby significantly improving electromagnetic energy dissipation efficiency. However, existing microwave absorbing material designs based on built-in electric fields are mostly single heterogeneous interface systems, with limited enhancement effects. Even when constructing dual heterogeneous interfaces, due to the randomness of component contact and the uncertainty of assembly order, charge transfer paths are often discontinuous, the directions of the built-in electric fields are inconsistent, the synergistic effect is not fully realized, and there is still considerable room for improvement in microwave absorption performance.

[0006] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of existing technologies. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the primary objective of this invention is to provide a T-ZnO@PANI / Ti3C2T x The preparation method of electromagnetic protection materials is simple and easy to operate.

[0008] The second objective of this invention is to provide a T-ZnO@PANI / Ti3C2T x Electromagnetic shielding materials have the characteristics of wide-band strong absorption, low filler load, high mechanical flexibility and no secondary pollution, and can be used as flexible electromagnetic shielding materials.

[0009] The third objective of this invention is to provide a T-ZnO@PANI / Ti3C2T x The application of electromagnetic protection materials has broad prospects.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A type of T-ZnO@PANI / Ti3C2T x The preparation method of electromagnetic shielding materials includes the following steps: To Ti3C2T x The zinc oxide@polyaniline composite material is added to the dispersion, ultrasonically dispersed, and then freeze-dried to obtain the final product.

[0011] Tetraneous zinc oxide whiskers (T-ZnO) are a typical wide-bandgap n-type semiconductor with a unique three-dimensional spatial configuration, consisting of four single-crystal needles extending outward from a central core. This naturally anisotropic structure not only allows them to overlap and form a macroscopic conductive network within a polymer matrix, but also acts as a microscopic "backbone" to suppress Ti3C2T. x The self-stacking of Ti3C2T. Meanwhile, T-ZnO, as a semiconductor, possesses a moderate dielectric constant and low conductivity, which can effectively modulate Ti3C2T. xExcessively high conductivity necessitates optimized system impedance matching. More importantly, Ti3C2T x There is a significant difference in work function between it and T-ZnO. When the two are in close contact, they will induce directional charge transfer at the interface, which can build a single built-in electric field and further enhance the interface polarization loss.

[0012] In this invention, polyaniline (PANI) acts as an electronic medium and bridge, firstly forming a tight core-shell interface with tetraneedle-shaped zinc oxide (T-ZnO) through in-situ polymerization, thus constructing the first built-in electric field of T-ZnO→PANI; then, through the interaction of PANI and Ti3C2T... x The close contact of PANI to construct Ti3C2T x The second built-in electric field. The two built-in electric fields are aligned in direction and follow continuous paths, forming a continuous dual built-in electric field with a stronger synergistic effect. This effectively improves carrier separation efficiency and enhances interfacial polarization relaxation loss under alternating electromagnetic fields. See the schematic diagram of charge transfer and the characteristics of the continuous dual built-in electric field. Figure 1 .

[0013] Furthermore, the zinc oxide@polyaniline, Ti3C2T x The mass ratio is 1:(0.025-0.1); the Ti3C2T x The concentration of the dispersion is 0.5-2 mg / mL.

[0014] Furthermore, the preparation method of the zinc oxide@polyaniline composite material is as follows: Add the dopant and stabilizer to water to obtain a mixed solution; add aniline monomer to the mixed solution, then add an oxidant solution to carry out a first polymerization reaction, then add a tetra-needle zinc oxide dispersion to carry out a second polymerization reaction, and after purification, the product is obtained.

[0015] Furthermore, the mass ratio of the aniline monomer, dopant, stabilizer, oxidant, and tetraneedle zinc oxide is 0.465:(2-2.2):(0.45-0.55):(1.1-1.2):(1.3-1.5); the dopant is dodecylbenzenesulfonic acid; the stabilizer is polyvinylpyrrolidone; and the oxidant is ammonium persulfate.

[0016] Furthermore, the concentration of the stabilizer in the mixed solution is 0.01-0.02 g / mL; the concentration of the oxidant solution is 0.2-0.3 g / mL; and the concentration of the tetraneedle-shaped zinc oxide dispersion is 0.09-0.1 g / mL.

[0017] Furthermore, the temperature of the first polymerization reaction is 0-5℃ and the time is 1.5-2.5 h; the temperature of the second polymerization reaction is 0-5℃ and the time is 1-2 h; and the time of the ultrasound is 10-20 min.

[0018] A type of T-ZnO@PANI / Ti3C2T x Electromagnetic shielding material is prepared using the above-described preparation method.

[0019] The above T-ZnO@PANI / Ti3C2T x The application of electromagnetic protection materials is used to prepare flexible electromagnetic protection products.

[0020] Furthermore, the flexible electromagnetic protection product is a flexible absorbing film or absorbing coating; the substrate of the flexible electromagnetic protection product is water-based polyurethane, rubber, or paraffin wax.

[0021] Furthermore, in flexible electromagnetic protection products, Ti3C2T x The nanosheets account for 0.5-1.5 wt% of the matrix.

[0022] The beneficial technical effects of this invention are as follows: 1. This invention uses in-situ polymerization to uniformly coat polyaniline onto the surface of tetrapter-shaped zinc oxide, forming a T-ZnO@PANI core-shell structure, and then applies Ti3C2T... x Nanosheets were tightly attached to the core-shell surface, successfully constructing T-ZnO@PANI / Ti3C2T x Electromagnetic shielding material. SEM, TEM, and mapping characterization confirmed that PANI is uniformly coated on the T-ZnO surface to form a core-shell structure, Ti3C2T. x The nanosheets are tightly adhered to the core-shell surface, exhibiting strong interfacial bonding. XPS electron transfer analysis further confirmed the presence of the "T-ZnO→PANI→Ti3C2T" sequence within the system. x The electron transfer path of "" conforms to the formation characteristics of a continuous dual built-in electric field.

[0023] 2. The electromagnetic protection material of the present invention has the characteristics of wide-band strong absorption, low filler load, high mechanical flexibility and no secondary pollution, and can be used as a flexible electromagnetic wave absorbing material.

[0024] 3. This invention analyzes the electromagnetic parameters of electromagnetic protection materials, and the results show that the appropriate introduction of Ti3C2T... x It can optimize the impedance matching of the system and enhance the attenuation capability. Among them, the ZPT1 sample exhibits the best absorption performance in the paraffin matrix: at a matching thickness of 1.48 mm, RL min Achieving -58.98 dB; EAB when the matched thickness is adjusted to 1.57 mm. maxThe 5.2 GHz band almost covers the entire Ku band (12.8–18.0 GHz). These results indicate that the "continuous dual built-in electric field" constructed based on the core-shell structure helps to enhance the synergistic effect between multiple interface polarization losses and conductivity losses.

[0025] 4. This invention also utilizes T-ZnO@PANI / Ti3C2T x A flexible composite film was prepared by incorporating a composite material into a polyurethane (WPU) matrix. Performance testing results showed that the composite film exhibited a high RL (reflectivity, ductility, and elasticity) at a thickness of 1.92 mm. min The electromagnetic induction voltage (EMV) reached -52.84 dB, maintaining excellent electromagnetic attenuation capability. Its tensile strength was 7.5 MPa, and its elongation at break remained above 500%, demonstrating excellent flexible deformation capability. Cross-sectional morphology showed that the filler was uniformly dispersed in the WPU matrix without significant agglomeration, and the interfacial bonding was good, indicating that this invention successfully prepared a flexible electromagnetic shielding film with both high microwave absorption performance and high flexibility.

[0026] 5. This invention also relates to T-ZnO@Ti3C2T x The absorption mechanism of the / PANI electromagnetic shielding material was investigated, and the results showed that: Ti3C2T x Nanosheets and PANI conductive shells overlap to form a three-dimensional continuous conductive network. Under the action of an alternating electric field, charge carriers migrate directionally, generating an induced current. Electromagnetic energy is dissipated in the form of Joule heating, providing the basic dielectric loss of the material. T-ZnO / PANI, PANI / Ti3C2T x The dual heterogeneous interface induces interfacial polarization loss; the difference in work function among the three components creates the "T-ZnO→PANI→Ti3C2T" pattern. x "The continuous dual built-in electric field significantly enhances polarization relaxation losses. Furthermore, Ti3C2T..." x The dipole centers formed by the polar functional groups, lattice defects, and defects on the PANI chains on the surface compensate for broadband losses through high-frequency orientation relaxation. Simultaneously, the T-ZnO three-dimensional framework and Ti3C2T... x The layered structure effectively extends the transmission path of electromagnetic waves, dissipating energy through multiple reflections and scattering. The synergistic effect of these multiple mechanisms enables the ZPT1 sample to achieve a strong absorption of -58.98 dB and a wideband response of 5.2 GHz at low addition levels, providing core support for its flexible applications. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the charge transfer and continuous dual built-in electric field characteristics of the present invention; Figure 2 It is Ti3C2T x SEM, TEM, and XRD images of nanosheets; Figure 3 The T-ZnO@PANI and T-ZnO@Ti3C2T obtained in Example 1 x SEM image of / PANI; Figure 4 The T-ZnO@PANI and T-ZnO@Ti3C2T obtained in Example 1 x TEM image of / PANI; Figure 5 This is a mapping analysis diagram of T-ZnO@PANI obtained in Example 1; Figure 6 It is the T-ZnO@Ti3C2T obtained in Example 1 x Mapping analysis diagram of / PANI; Figure 7 The T-ZnO@PANI and T-ZnO@Ti3C2T obtained in Example 1 x XRD pattern of / PANI; Figure 8 The T-ZnO@PANI and T-ZnO@Ti3C2T obtained in Example 1 x FTIR plot of / PANI; Figure 9 The T-ZnO@PANI and T-ZnO@Ti3C2T obtained in Example 1 x XPS graph of / PANI; Figure 10 The graph shows the electromagnetic wave absorption performance of various ZPT / PW composite materials. Figure 11 This is a graph showing the electromagnetic parameters of the ZPT / PW composite material. Figure 12 The graph shows the attenuation constant α and normalized impedance Z of each ZPT / PW composite material. Figure 13 These are the results of polarization relaxation behavior in various ZPT / PW composite material systems; Figure 14 This is a schematic diagram of the microwave absorption mechanism of ZPT / PW composite material; Figure 15 This is a diagram showing the electromagnetic attenuation capability of the ZPT / WPU composite film; Figure 16 These are the mechanical properties of the ZPT / WPU composite film; Figure 17 This is a topographic image of the fracture surface of a ZPT / WPU composite film sample; Figure 18 This is a SEM image of the liquid nitrogen brittle fracture surface of the ZPT / NR composite material; Figure 19This is a graph showing the electromagnetic wave absorption performance of the ZPT / NR composite material. Detailed Implementation

[0028] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0029] The solid content of the polyurethane emulsion (WPU) of this invention is 55 wt.%.

[0030] In this invention, Ti3C2T x The preparation method of nanosheets is as follows: 8 g of LiF was dissolved in 100 mL of 9 mol / L hydrochloric acid solution, and after stirring for 15 min, 5 g of 400 mesh Ti3AlC2 powder was slowly added. The mixture was stirred at 40 °C for 42 h. After stirring, the mixture was centrifuged at 3500 rpm for 1 min, and the precipitate was repeatedly washed with deionized water until the pH of the supernatant reached 5-6. Then, the mixture was sonicated in an ice-water bath and under an inert atmosphere for 1 h. After sonication, it was centrifuged at 3500 rpm for 45 min, and the supernatant was collected to obtain a monolayer of Ti3C2T. x Nanosheet dispersion. Monolayer Ti3C2T was prepared using a freeze dryer. x The nanosheet dispersion was freeze-dried to obtain Ti3C2T. x The nanosheets were stored in a refrigerator at 3°C ​​under a nitrogen atmosphere until they were ready for use.

[0031] Example 1 A type of T-ZnO@PANI / Ti3C2T x The preparation method of electromagnetic shielding materials includes the following steps: 0.008g Ti3C2T x Nanosheets were added to 10 mL of deionized water and ultrasonically dispersed under ice-water bath conditions to prepare a uniform and stable 0.8 mg / mL Ti3C2T solution. x Dispersion; Weigh 0.16 g of tetraneedle-shaped zinc oxide@polyaniline composite material (T-ZnO@PANI) and slowly add it to Ti3C2T x In the dispersion, continue ultrasonic dispersion for 15 min to allow the T-ZnO@PANI particles to react with Ti3C2T. xThe nanosheets were thoroughly mixed to form a homogeneous blend suspension. Finally, the blend suspension was pre-frozen in liquid nitrogen and then freeze-dried to obtain T-ZnO@PANI / Ti3C2T. x The powder was named ZPT1.

[0032] The preparation method of the above T-ZnO@PANI composite material is as follows: To prepare an ammonium persulfate (APS) solution: Dissolve 1.14 g of APS in 5 mL of deionized water and cool to 0 °C. Preparation of tetraneedle-shaped zinc oxide (T-ZnO) dispersion: Disperse 1.4 g of T-ZnO ultrasonically in 15 mL of deionized water to obtain the solution. 2.04 g of dodecylbenzenesulfonic acid (DBSA) was dissolved in 50 mL of deionized water, and 0.5 g of polyvinylpyrrolidone (PVP K30) was added. The mixture was stirred for 15 min until completely dissolved to obtain a mixed solution. Then, 0.005 mol of ANI (aniline) purified by vacuum distillation was added to the above mixed solution, and the mixture was stirred thoroughly for 30 min to ensure uniform dispersion. The mixture was then cooled to 0°C using an ice-water bath. APS aqueous solution was then slowly added dropwise, with the dropping rate controlled and the reaction temperature maintained at 4°C. After 2 h of reaction, T-ZnO dispersion was slowly added to the reaction system, and the reaction was continued for 1.5 h. After the reaction was completed, the mixture was vacuum filtered. The resulting filter cake was washed repeatedly with anhydrous ethanol and deionized water to remove unreacted monomers and impurities. Finally, the mixture was dried in a vacuum drying oven at 60°C for 24 h and then ground to obtain the T-ZnO@PANI composite material.

[0033] A type of T-ZnO@PANI / Ti3C2T x Electromagnetic shielding material is prepared using the above-described preparation method.

[0034] Example 2 A type of T-ZnO@PANI / Ti3C2T x The preparation method of electromagnetic shielding materials includes the following steps: 0.016g Ti3C2T x Nanosheets were added to 10 mL of deionized water and ultrasonically dispersed under ice-water bath conditions to prepare a homogeneous and stable 1.6 mg / mL Ti3C2T solution. x Dispersion; Weigh 0.16 g of tetraneedle-shaped zinc oxide@polyaniline composite material (T-ZnO@PANI) and slowly add it to Ti3C2T x In the dispersion, continue ultrasonic dispersion for 15 min to allow the T-ZnO@PANI particles to react with Ti3C2T. xThe nanosheets were thoroughly mixed to form a homogeneous blend suspension. Finally, the blend suspension was pre-frozen in liquid nitrogen and then freeze-dried to obtain T-ZnO@PANI / Ti3C2T. x The powder was named ZPT2.

[0035] The preparation method of the above T-ZnO@PANI composite material is as follows: To prepare an ammonium persulfate (APS) solution: Dissolve 1.14 g of APS in 5 mL of deionized water and cool to 0 °C. Preparation of tetraneedle-shaped zinc oxide (T-ZnO) dispersion: Disperse 1.4 g of T-ZnO ultrasonically in 15 mL of deionized water to obtain the solution. 2.04 g of dodecylbenzenesulfonic acid (DBSA) was dissolved in 50 mL of deionized water, and 0.5 g of polyvinylpyrrolidone (PVP K30) was added. The mixture was stirred for 15 min until completely dissolved to obtain a mixed solution. Then, 0.005 mol of ANI purified by vacuum distillation was added to the mixed solution, and the mixture was stirred thoroughly for 30 min to ensure uniform dispersion. The mixture was then cooled to 0 °C using an ice-water bath. APS aqueous solution was then slowly added dropwise, with the dropping rate controlled and the reaction temperature maintained at 4 °C. After 2 h of reaction, T-ZnO dispersion was slowly added to the reaction system, and the reaction was continued for 1.5 h. After the reaction was completed, the mixture was vacuum filtered. The resulting filter cake was washed repeatedly with anhydrous ethanol and deionized water to remove unreacted monomers and impurities. Finally, the mixture was dried in a vacuum drying oven at 60 °C for 24 h and then ground to obtain the T-ZnO@PANI composite material.

[0036] A type of T-ZnO@PANI / Ti3C2T x Electromagnetic shielding material is prepared using the above-described preparation method.

[0037] Example 3 A T-ZnO@PANI / Ti3C2T-based x The method for preparing electromagnetic shielding materials includes the following steps: 0.004g Ti3C2T x Nanosheets were added to 10 mL of deionized water and ultrasonically dispersed under ice-water bath conditions to prepare a homogeneous and stable 0.4 mg / mL Ti3C2T solution. x Dispersion; Weigh 0.16g T-ZnO@PANI and slowly add it to Ti3C2T x In the dispersion, continue ultrasonic dispersion for 20 min to allow the T-ZnO@PANI particles to react with Ti3C2T. xThe nanosheets were thoroughly mixed to form a homogeneous blend suspension. Finally, the blend suspension was pre-frozen in liquid nitrogen and then freeze-dried to obtain T-ZnO@PANI / Ti3C2T. x The powder was named ZPT3.

[0038] The preparation method of the above T-ZnO@PANI composite material is as follows: To prepare ammonium persulfate (APS) solution: Dissolve 1.2 g APS in 5 mL of deionized water and cool to 0 °C. Preparation of tetraneedle-shaped zinc oxide (T-ZnO) dispersion: Disperse 1.5g of T-ZnO ultrasonically in 15mL of deionized water to obtain the solution. 2.2 g DBSA was dissolved in 50 mL of deionized water, and 0.55 g PVP K30 was added. The mixture was stirred for 15 min until completely dissolved to obtain a mixed solution. Then, 0.005 mol of ANI purified by vacuum distillation was added to the mixed solution, and the mixture was stirred thoroughly for 30 min to ensure uniform dispersion. The mixture was then cooled to 0 °C using an ice-water bath. APS aqueous solution was then slowly added dropwise, with the dropping rate controlled and the reaction temperature maintained at 0 °C. After 2.5 h of reaction, T-ZnO dispersion was slowly added to the reaction system, and the reaction was continued for another 2 h. After the reaction was completed, the mixture was vacuum filtered. The resulting filter cake was washed repeatedly with anhydrous ethanol and deionized water to remove unreacted monomers and impurities. Finally, the mixture was dried in a vacuum drying oven at 60 °C for 24 h and then ground to obtain the T-ZnO@PANI composite material.

[0039] A type of T-ZnO@PANI / Ti3C2T x Electromagnetic shielding material is prepared using the above-described preparation method.

[0040] Example 4 A type of T-ZnO@PANI / Ti3C2T x The preparation method of electromagnetic shielding materials includes the following steps: 0.012g Ti3C2T x Nanosheets were added to 10 mL of deionized water and ultrasonically dispersed under ice-water bath conditions to prepare a homogeneous and stable 1.2 mg / mL Ti3C2T solution. x Dispersion; Weigh 0.16g T-ZnO@PANI and slowly add it to Ti3C2T x In the dispersion, continue ultrasonic dispersion for 10 min to allow the T-ZnO@PANI particles to react with Ti3C2T. x The nanosheets were thoroughly mixed to form a homogeneous blend suspension. Finally, the blend suspension was pre-frozen in liquid nitrogen and then freeze-dried to obtain T-ZnO@PANI / Ti3C2T. xThe powder was named ZPT4.

[0041] The preparation method of the above T-ZnO@PANI composite material is as follows: To prepare ammonium persulfate (APS) solution: Dissolve 1.1 g APS in 5 mL of deionized water and cool to 0 °C. Preparation of tetraneedle-shaped zinc oxide (T-ZnO) dispersion: Disperse 1.3g of T-ZnO ultrasonically in 15 mL of deionized water to obtain the solution. 2.1 g DBSA was dissolved in 50 mL of deionized water, and 0.45 g PVP K30 was added. The mixture was stirred for 15 min until completely dissolved to obtain a mixed solution. Then, 0.005 mol of ANI purified by vacuum distillation was added to the mixed solution, and the mixture was stirred thoroughly for 30 min to ensure uniform dispersion. The mixture was then cooled to 0 °C using an ice-water bath. APS aqueous solution was then slowly added dropwise, with the dropping rate controlled and the reaction temperature maintained at 5 °C. After reacting for 1.5 h, T-ZnO dispersion was slowly added to the reaction system, and the reaction was continued for another 1 h. After the reaction was completed, the mixture was vacuum filtered. The resulting filter cake was washed repeatedly with anhydrous ethanol and deionized water to remove unreacted monomers and impurities. Finally, the mixture was dried in a vacuum drying oven at 60 °C for 24 h and then ground to obtain the T-ZnO@PANI composite material.

[0042] A type of T-ZnO@PANI / Ti3C2T x Electromagnetic shielding material is prepared using the above-described preparation method.

[0043] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that Ti3C2T was not added. x The nanosheets were named ZPT0.

[0044] Comparative Example 2 Weigh out 8.0 mg Ti3C2T x Nanosheets were dispersed in 10 mL of deionized water and sonicated in an ice-water bath for 30 min to redisperse them uniformly, yielding stable Ti3C2T. x An aqueous dispersion (concentration 0.8 mg / mL) was prepared. 126.0 mg of T-ZnO powder was added to this dispersion, and the mixture was sonicated for 15 min to ensure homogeneity. Subsequently, 34.0 mg of PANI nanofiber powder (calculated according to the PANI to T-ZnO ratio in Preparation Example 1) was added, and the mixture was magnetically stirred for 15 min. Finally, the resulting mixture was pre-frozen in liquid nitrogen and then freeze-dried at -50℃ and <10 Pa for 48 h to obtain T-ZnO / Ti3C2T. x PANI powder, denoted as ZTP.

[0045] Experimental Example 1 The prepared Ti3C2T was analyzed using field emission scanning electron microscopy (SEM), field emission transmission electron microscopy (TEM), and X-ray diffraction (XRD). x The morphology of the nanosheets was observed, and the results are as follows: Figure 2 As shown.

[0046] Figure 2 It is Ti3C2T x SEM, TEM, and XRD images of the nanosheets. (a) is the SEM image of Ti3AlC2. As can be seen from the image, Ti3AlC2 exhibits a blocky, layered structure with a relatively rough surface and tightly packed layers. Figure (b) shows the Ti3C2 nanosheets after freeze-drying. x The SEM images show that, compared to the original Ti3AlC2, after fluoride salt etching and ultrasonic ablation, the Al layer in Ti3AlC2 was selectively etched away, forming Ti3C2T with obvious interlayer exfoliation characteristics. x Furthermore, there are certain gaps between the layers, indicating that the layered material has been successfully exfoliated. Figure (c) shows Ti3C2T x The TEM image further confirms Ti3C2T x The successful fabrication of nanosheets, as shown in the image, reveals large-sized, transparent, and wrinkled sheet structures, indicating the successful preparation of monolayer Ti3C2T. x Nanosheets. Figure (d) shows the original MAX phase Ti3AlC2 and the exfoliated Ti3C2T. x The XRD pattern of Ti3AlC2. Several clear characteristic diffraction peaks, such as (002), (004), and (100), can be observed in the XRD pattern of Ti3C2. After etching and stripping, Ti3C2T x In the XRD spectrum of Ti3AlC2, several characteristic diffraction peaks weakened or even disappeared, and the diffraction peak corresponding to the (002) crystal plane shifted towards smaller angles, from 2θ≈9.7° to about 7.5°. According to the Bragg equation 2dsinθ = nλ, the shift of the diffraction angle towards smaller angles (i.e., the decrease of 2θ) implies an increase in the interplanar spacing d, indicating that after etching, Ti3C2T x The interlayer spacing increased, indicating effective exfoliation between the Ti3AlC2 layers. Simultaneously, the (002) diffraction peak broadened, further supporting the evidence for the increased interlayer spacing of Ti3C2. x Successful preparation.

[0047] Experiment Example 2 The T-ZnO@PANI and T-ZnO@PANI / Ti3C2T samples obtained in Example 1 were analyzed by field emission scanning electron microscopy (SEM). x The morphological characteristics were observed, and the results are shown in [reference]. Figure 3 .

[0048] Figure 3 The T-ZnO@PANI and T-ZnO@Ti3C2T obtained in Example 1 x SEM images of PANI. Figure (a) shows the SEM image of T-ZnO, which has a smooth and flat surface with sharp edges. Figure (b) shows the SEM image of T-ZnO@PANI. After in-situ chemical oxidation polymerization coating with PANI, the T-ZnO@PANI composite material still retains the original four-needle skeleton structure, but the surface becomes significantly rougher and is accompanied by granular deposits. This indicates that PANI has been successfully and uniformly polymerized and coated on the T-ZnO surface. Figure (c) shows the further introduction of Ti3C2T x The SEM morphology of the ZPT composite material prepared by nanosheets shows that a thin film-like substance is attached to the rough T-ZnO@PANI framework surface, indicating that the two-dimensional Ti3C2T x The nanosheets formed a good bond with T-ZnO@PANI.

[0049] Experimental Example 3 The T-ZnO@PANI and T-ZnO@PANI / Ti3C2T samples obtained in Example 1 were analyzed by field emission transmission electron microscopy (TEM). x The microstructure was observed, and the results are shown in [reference]. Figure 4 .

[0050] Figure 4 The T-ZnO@PANI and T-ZnO@PANI / Ti3C2T obtained in Example 1 x TEM images of the original T-ZnO are shown in Figure (a). This image further confirms the tetraneedle-like structure of T-ZnO, consistent with the morphology observed by SEM. Figure (b) shows a TEM image of the T-ZnO@PANI composite material. The material exhibits an extremely dark solid outline inside, corresponding to the T-ZnO core with high electron density, while the edges show a translucent rough layer, confirming the presence of the PANI polymer coating layer. Figure (c) further demonstrates in the high-resolution TEM image that an ultrathin two-dimensional sheet-like structure is tightly attached to the darker substrate edge. This phenomenon intuitively proves the existence of Ti3C2T x MXene nanosheets and T-ZnO@PANI particles achieved a tight interfacial bond, successfully constructing T-ZnO@PANI / Ti3C2T x Composite system.

[0051] Experiment Example 4 The T-ZnO@PANI and T-ZnO@PANI / Ti3C2T obtained in Example 1 x A mapping analysis was performed; the results can be found here. Figure 5-6 .

[0052] Figure 5 This is a mapping analysis diagram of T-ZnO@PANI. (a) represents Zn elements, (b) represents O elements, (c) represents C elements, and (d) represents N elements. Figure 6 It is T-ZnO@PANI / Ti3C2T x The mapping analysis diagram is shown below. (a) represents Zn elements, (b) represents O elements, (c) represents N elements, (d) represents C elements, and (e) represents Ti elements. From... Figure 5 It can be clearly observed that the signals of Zn and O elements reveal the tetrapod-like framework outline of the internal T-ZnO. Simultaneously, C and N elements, representing the PANI component, are also uniformly distributed throughout the tetrapod-like structure. The consistent spatial distribution of Zn, O, C, and N elements indicates that PANI has successfully coated the surface of T-ZnO, forming a T-ZnO@PANI core-shell structure. Figure 6 In addition to the existing Zn, O, N, and C elements, Ti was also observed. Ti was observed as Ti3C2T. x The characteristic elements of MXene show that their elemental signal distribution is basically consistent with that of Zn, O, C, and N. This indicates that after ultrasonic and freeze-drying treatment, Ti3C2T... x MXene nanosheets have been successfully introduced into the system and uniformly adhered to the surface of T-ZnO@PANI. EDS analysis results are consistent with SEM and TEM morphology characterization results, jointly confirming the T-ZnO@PANI / Ti3C2T... x Successful construction of a ternary composite system.

[0053] Experimental Example 5 X-ray diffraction (XRD) was used to analyze the T-ZnO@PANI and T-ZnO@PANI / Ti3C2T samples obtained in Example 1. x Structural analysis was performed; results can be found in [link to relevant documentation]. Figure 7 .

[0054] Figure 7 The T-ZnO@PANI and T-ZnO@PANI / Ti3C2T obtained in Example 1 x The XRD pattern. Observe. Figure 7 It is known that in the T-ZnO@PANI binary composite, the main diffraction peak of T-ZnO is well preserved without significant shift, indicating that the PANI coating does not destroy the crystal structure of ZnO itself. The introduction of Ti3C2T... x Afterwards, T-ZnO@PANI / Ti3C2T xSignificant changes occurred in the XRD pattern, with a novel diffraction peak appearing in the low-angle region at 2θ≈6.9°, corresponding to Ti3C2T. x The (002) crystal plane, which is a characteristic peak of layered MXene, proves that Ti3C2T x It was successfully introduced into the system. At the same time, a broad diffraction peak appeared in the range of 2θ ≈ 10~20°, which is a typical characteristic peak of amorphous PANI. Its signal enhancement may be related to the interfacial interaction between PANI and MXene surface.

[0055] Experimental Example 6 Fourier transform infrared spectroscopy (FTIR) was used to analyze the T-ZnO@PANI and T-ZnO@PANI / Ti3C2T samples obtained in Example 1. x Structural analysis was performed; results can be found in [link to relevant documentation]. Figure 8 .

[0056] Figure 8 The T-ZnO@PANI and T-ZnO@PANI / Ti3C2T obtained in Example 1 x The FTIR plot. Observe. Figure 8 It is known that pure T-ZnO at 510 cm⁻¹ -1 Characteristic Zn-O stretching vibration peaks can be observed nearby. After the introduction of PANI, a typical PANI absorption band appears in the binary composite system, at 1560 cm⁻¹. -1 The -C=N stretching vibration peak of the quinone ring at 1300 cm⁻¹ -1 The peak at 1130 cm⁻¹ corresponds to the -CN stretching vibration of aromatic secondary amines. -1 The strong absorption peak at this point is attributed to the N=Q=N vibration of the polaron structure in the conductive state of PANI (emerald green imine salt), indicating that PANI is in a conductive active state. Furthermore, at approximately 3400 cm⁻¹... -1 A -NH stretching vibration peak appears at T-ZnO@PANI / Ti3C2T. x In the FTIR spectrum of the ternary composite material, the characteristic absorption peaks of PANI and ZnO were retained, indicating that each component maintained the integrity of its chemical structure during the composite process.

[0057] Experimental Example 7 The T-ZnO@PANI and T-ZnO@PANI / Ti3C2T obtained in Example 1 x XPS analysis was performed; results can be found here. Figure 9 .

[0058] Figure 9 The T-ZnO@PANI and T-ZnO@PANI / Ti3C2T obtained in Example 1 xXPS images are shown. (a) is the full spectrum scan, (b) is the C 1s spectrum, (c) is the Ti 2p spectrum, (d) is the N 1s spectrum, and (e) is the O 1s spectrum. Observing Figure (a), the characteristic peaks of Zn 2p, O 1s, C 1s, and N 1s are clearly visible in the full spectrum of T-ZnO@PANI, indicating good recombination between T-ZnO and PANI. The introduction of Ti3C2T... x Afterwards, T-ZnO@PANI / Ti3C2T x The full spectrum shows new Ti 2p peaks at approximately 458 eV and F 1s peaks at approximately 685 eV, corresponding to Ti3C2T, respectively. x The presence of Ti element and its surface -F functional groups preliminarily confirms the T-ZnO@PANI / Ti3C2T x The ternary composite system was successfully constructed. Next, the core elements were analyzed. In the C 1s spectrum, T-ZnO@PANI / Ti3C2T... x In addition to retaining the typical CC / C=C (approximately 284.8 eV) and CN / CO (approximately 286.2 eV) characteristic peaks of PANI, a clear peak corresponding to Ti3C2T is visible at 281.5 eV. x The presence of C-Ti and C-Ti-O bonds confirms that MXene has been successfully introduced into the system and interacts with PANI at the interface. Simultaneously, in the Ti 2p spectrum, Ti3C2T... x Multivalent characteristics (Ti-C, Ti) 2+ Ti 3+ The presence of Ti-O and Ti-O is still present, but the proportion and binding energy position of some Ti-O and high-valence Ti peaks have been slightly adjusted, indicating that oxygen-containing end groups (-OH, -O) on the MXene surface participate in the bonding process of the heterostructure interface.

[0059] The redistribution of interfacial charges was further confirmed in the N 1s and O 1s spectra. Compared with the binary system T-ZnO@PANI, the N 1s main peak of PANI in the ternary system shifted significantly towards higher binding energies (from 399.00 eV to 400.82 eV), with a significant decrease in the intensity of the -N= peak, while the polaron / protonated nitrogen (-NH- / -NH) peak at 401 eV was significantly reduced. + -) The peak becomes the dominant component. The increase in the N 1s binding energy implies a decrease in the electron cloud density around the nitrogen atom, indicating that PANI acts as an "electron bridge" in the heterostructure interface, accepting electrons from low work function T-ZnO on the one hand, and receiving electrons from high work function Ti3C2T on the other. xDriven by MXene, a large number of electrons transfer to MXene, resulting in an electron-deficient state in PANI. Furthermore, the O 1s spectrum also confirms this electron transfer process. In the binary system, the lattice oxygen (Zn-O) peak of T-ZnO is located at approximately 530.5 eV, while in the ternary system, this peak shifts towards a lower binding energy direction to approximately 529.6 eV, indicating an increase in the electron cloud density around the lattice oxygen. This phenomenon does not signify a reversal of the electron flow direction, but rather reflects the regulatory effect of MXene on the charge distribution at the heterostructure interface. Combining the changes in the orbitals of each element, it can be inferred that the electron transfer order in the ternary composite material is T-ZnO → PANI → Ti3C2T. x PANI acts as an electronic mediator and bridge, promoting the formation of the built-in electric field at the interface and improving the efficiency of charge carrier separation, thereby optimizing the overall charge transport performance of the material.

[0060] Experimental Example 8 To visually evaluate the electromagnetic wave absorption performance of the prepared ZPT / PW samples, the RL of each composite material in the frequency range of 2-18 GHz was calculated based on transmission line theory. The specific experimental procedure is as follows: 0.8g of paraffin wax was heated and melted, and then the ZPT composite materials obtained in Examples 1-2 and Comparative Example 1 were added respectively. The mixture was continuously stirred to ensure uniform dispersion in the paraffin matrix. Then, it was pressed into a coaxial mold while hot. After cooling and molding, ZPT / PW composite coaxial test rings were obtained. Based on the naming of the examples or comparative examples, they were named ZPT0 / PW, ZPT1 / PW, and ZPT2 / PW respectively. Their electromagnetic wave absorption performance was evaluated, and the results are as follows: Figure 10 As shown.

[0061] Figure 10 This is a graph showing the electromagnetic wave absorption performance of various ZPT / PW composite materials. For example... Figure 10 (ac) shows the implementation without the introduction of Ti3C2T x The absorption performance of the ZPT0 sample is shown in the figure. It can be seen that its electromagnetic wave attenuation capability is limited, even at a relatively large thickness of 5.00 mm. min It can only reach -14.45 dB, EAB max The frequency band is only 2.84 GHz, and the absorption band is significantly discontinuous. This indicates that relying solely on a single binary heterostructure is insufficient to build an effective conductive network within the material and leverage the synergistic effect of multiple interfaces. Figure 10 (df) indicates that: with the introduction of an appropriate amount of Ti3C2T x After forming the ternary composite material, the microwave absorption performance of the ZPT1 sample was significantly improved. As can be visually observed from the three-dimensional RL surface plot in Figure (e), the RL of ZPT1 at a thickness of 1.48 mm... minIt reached -58.98 dB, demonstrating extremely strong electromagnetic wave attenuation capability. Furthermore, the 2D contour plot in Figure (f) further confirms that when the thickness is adjusted to 1.57 mm, its EAB... max Reaching 5.2 GHz (covering 12.8-18.0 GHz), it basically achieves effective coverage of the entire Ku band. Figure 10 (gi) indicates that the RL of ZPT2 min -27.98 dB, EAB max It is 3.58 GHz.

[0062] Experimental Example 9 To reveal the underlying mechanism of the differences in microwave absorption performance of the ZPT / PW composite system, a vector network analyzer was used to test the changes in electromagnetic parameters of the ZPT / PW composite film in the 2-18 GHz frequency band at room temperature using the waveguide method. The sample size was 20 mm × 35 mm. During the test, each sample was carefully fixed to the fixture with transparent tape. The preparation method of the ZPT / PW composite material was the same as in Experiment 7. The results are as follows. Figure 11 As shown.

[0063] Figure 11 Figures (b) and (d) show the electromagnetic parameters of the ZPT / PW composite material. As shown in Figures (b) and (d), within the 2-18 GHz test frequency band, the real part of the permeability (μ′) of all samples fluctuates slightly around 1.0, the imaginary part (μ′′) is approximately zero, and the magnetic loss tangent (tanδ) is relatively low. μ Extremely low (Figure f). This is consistent with Ti3C2T x The fact that PANI and T-ZnO are all non-magnetic materials with consistent properties proves that the electromagnetic attenuation of this composite system mainly depends on the dielectric loss mechanism.

[0064] Figures (a) and (c) show the variation of ε′ and ε′′ of the samples with frequency. Overall, ε′ and ε′′ of all samples exhibit typical dispersion characteristics, gradually decreasing with increasing frequency. Simultaneously, it can be clearly observed that the magnitude of the dielectric parameter significantly affects the performance of Ti3C2T. x The doping level is highly sensitive. Specifically, ZPT0 samples lacking a continuous conductive network exhibit low ε′ and ε′′ values. When Ti3C2T is introduced... x Subsequently, a three-dimensional microcurrent network was constructed within the system. According to the free electron theory, the increase in macroscopic conductivity manifests as an increase in the ε′′ value, indicating that the material's conductivity loss capability is enhanced. Typically, the dielectric loss tangent (tanδ) is used... ε This measures the overall efficiency of a material in converting electromagnetic energy into thermal energy. Figure e shows that although Ti3C2T... x The ZPT2 with high content has the highest ε′′ value, but exhibits the highest tanδ.ε However, the ZPT1 sample exhibits the best absorption performance. Careful observation reveals that the tanδ of ZPT1 in Figure (c) is... ε Multiple broadband resonance peaks appeared near 8 GHz, 13 GHz, and 15 GHz in the curves and ε′′ curves. The manifestation of these multiple resonance peaks in macroscopic electromagnetic parameters is actually a mapping of the interaction between multiple heterostructures and the dual built-in electric field (DBEIF) at the microscopic scale. This is due to the interfacial polarization relaxation excited by the built-in electric field, and the interaction between PANI and Ti3C2T. x The two microscopic mechanisms, namely, dipole polarization induced by surface end groups (-OH, -F, etc.), together lay the foundation for the excellent microwave absorption performance of the ZPT1 sample.

[0065] Experimental Example 10 The actual absorption performance of the material depends on the trade-off between its internal electromagnetic energy dissipation capability (high α value) and impedance matching characteristics (Z≈1.0). The attenuation constant α and normalized impedance Z of each ZPT / PW composite material were measured. The preparation method of the ZPT / PW composite material was the same as in Experiment 7. The results are as follows: Figure 12 As shown.

[0066] Figure 12 This is a graph showing the attenuation constant α and normalized impedance Z of each ZPT / PW composite material. (Example:) Figure 12 As shown, the attenuation capability of all samples increases with increasing frequency. ZPT0 exhibits the lowest α value due to the lack of a continuous conductive network and sufficient heterojunction. The introduction of Ti3C2T... x Subsequently, the α values ​​of both ZPT1 and ZPT2 increased significantly. It is noteworthy that, although the Ti3C2T of ZPT1... x While its content is lower than that of ZPT2, its α curve exhibits a significant broadband attenuation resonance peak in the mid-to-low frequency range of 6-10 GHz, with the peak value approaching that of ZPT2. Based on the microscopic analysis described above, it is speculated that this localized enhanced attenuation originates from the DBEIF mechanism within the system, which contributes a substantial amount of interfacial polarization loss, thereby giving the ZPT1 sample superior electromagnetic wave attenuation capabilities.

[0067] Although ZPT2 has the highest α value, its macroscopic wave absorption performance is worse than ZPT1. This may be due to impedance mismatch; ideal impedance matching requires a Z value close to 1.0 to allow electromagnetic waves to penetrate as much as possible into the material. Figure 11 As shown in (b), at the optimal matching thickness (1.27 mm), the Z-value curve of ZPT2 is generally below 1.0. This is likely due to the excess Ti3C2T. xThe excessively high ε′ of the ZPT2 sample induces the skin effect, resulting in the reflection of a large amount of electromagnetic waves at the material surface. In contrast, the ZPT1, with an extremely thin thickness of 1.48 mm, exhibits a Z-value curve that closely approximates the Z = 1.0 baseline within the 12-18 GHz range, indicating optimized impedance matching. In summary, the ZPT1 composite material achieves strong absorption and wide bandwidth at a relatively thin thickness due to its well-balanced impedance matching characteristics and multiple loss mechanisms.

[0068] Experimental Example 11 Based on the Debye relaxation model, the polarization relaxation behavior of each ZPT / PW composite system was further analyzed using Cole-Cole curves. The preparation method of the ZPT / PW composite was the same as in Experiment 7, and the results are as follows: Figure 13 As shown.

[0069] Figure 13 These are the results of polarization relaxation behavior in various ZPT / PW composite material systems. For example... Figure 13 As shown in (a), the Cole-Cole curve of the ZPT0 sample does not exhibit a distinct semicircular characteristic, indicating its weak polarization relaxation response. Figure 13 As shown in (b), in the ZPT1 system, the curve exhibits multiple continuous Cole-Cole semicircles, connected at the tail by a straight line with a moderate slope. The existence of multiple semicircles proves the presence of abundant polarization centers within the system, which is attributed to a suitable amount of Ti3C2T. x The introduction of [a specific element] induces the construction of the DBEIF. Under the influence of an electromagnetic field, the space charge bound at the heterogeneous interface undergoes displacement and high-frequency oscillation, triggering a multi-interfacial polarization relaxation effect. For example... Figure 13 As shown in (c), the dipole orientation polarization of the MXene surface functional groups and PANI polar groups under an alternating electric field also contributes to the formation of the semicircle. When Ti3C2T in the system... x When the content is too high, the curve appears as a small semicircle followed by a dominant straight line tail. This indicates an excess of Ti3C2T. x A highly interconnected conductive network is formed, causing conduction losses to mask polarization relaxation behavior. This aligns with the conclusion in impedance matching analysis that "excessive conductivity induces the skin effect." In summary, the microwave absorption mechanism of ZPT1 is not a single energy dissipation mode, but rather relies on a suitable conductive network to ensure impedance matching and utilizes dual built-in electric fields to excite high-intensity multi-interface polarization relaxation. The effective synergy between conduction losses and multi-polarization losses jointly endows the material with excellent microwave absorption characteristics.

[0070] Based on the above analysis of electromagnetic parameter evolution, attenuation characteristics, and dielectric relaxation behavior, T-ZnO@PANI / Ti3C2T x The microwave absorption mechanism of the composite material is as follows: Ti3C2Tx Nanosheets and PANI conductive shells overlap to form a three-dimensional continuous conductive network. Under the influence of an alternating electric field, charge carriers migrate directionally, generating an induced current. This current dissipates electromagnetic energy as Joule heating, providing the material's fundamental dielectric loss. The difference in work function among the three components creates the "T-ZnO→PANI→Ti3C2T" pattern. x "The continuous dual built-in electric field significantly enhances polarization relaxation losses. Furthermore, Ti3C2T..." x The dipole centers formed by the polar functional groups, lattice defects, and defects on the PANI chains on the surface compensate for broadband losses through high-frequency orientation relaxation. Simultaneously, the T-ZnO three-dimensional framework and Ti3C2T... x The layered structure effectively extends the electromagnetic wave propagation path, dissipating energy through multiple reflections and scattering. The synergistic effect of these multiple mechanisms enables the ZPT1 sample to achieve a strong absorption of -58.98 dB and a wideband response of 5.2 GHz even with low addition levels, providing core support for its flexible applications. See the corresponding mechanism diagram below. Figure 14 As shown.

[0071] Experimental Example 12 The dried ZPT composite materials from Example 1 and Comparative Example 1 were mixed evenly with WPU emulsion, then transferred to a non-invasive slurry homogenizer for degassing for 2 minutes. The mixture was then carefully poured into a polytetrafluoroethylene mold and dried at 50°C for 36 hours. After complete evaporation of moisture, the film was peeled off the mold to obtain the film, which was named ZPT0 / WPU and ZPT1 / WPU (Ti3C2T) according to the naming conventions of the examples or comparative examples. x The microwave absorption properties of the composite material in a flexible polymer matrix were investigated (using 1 wt% of the WPU solid content). The results are as follows: Figure 15 As shown.

[0072] Figure 15 This is a diagram showing the electromagnetic attenuation capability of the composite thin film. Specifically, (a) is the 2D RL diagram of the reflection loss of the ZPT0 / WPU thin film, (b) is the 3D RL diagram of the ZPT0 / WPU thin film, (c) is the 2D contour RL diagram of the ZPT0 / WPU thin film, (d) is the 2D RL diagram of the reflection loss of the ZPT1 / WPU thin film, (e) is the 3D RL diagram of the ZPT1 / WPU thin film, and (f) is the 2D contour RL diagram of the ZPT1 / WPU thin film. Figure 15 It can be seen that the ZPT1 / WPU composite film maintains good electromagnetic attenuation capability. When the matching thickness is 1.92 mm, its RL... minThe impedance reached -52.84 dB. Compared to the ZPT0 / WPU sample without MXene (optimal matching thickness 4.82 mm), the matching thickness of ZPT1 / WPU was significantly reduced, indicating that the addition of MXene helps improve the impedance matching of the system and effectively reduce the thickness. It is worth noting that due to the different dielectric constants of the WPU matrix and paraffin, the overall impedance matching conditions of the composite film change, resulting in broadband absorption (EAB) for ZPT1 / WPU. max The matching thickness (corresponding to 2.66 GHz) was shifted to 3.46 mm. Overall, the ZPT1 filler can still effectively attenuate electromagnetic waves in the WPU matrix, and the prepared composite film exhibits a thin matching thickness and strong absorption intensity, which meets the design requirements of thin and light absorbing materials.

[0073] Experimental Example 13 The dried ZPT composite materials from Examples 1 and Comparative Examples 1-2 were mixed evenly with WPU emulsion, then transferred to a non-invasive slurry homogenizer for degassing for 2 minutes. The mixture was then carefully poured into a polytetrafluoroethylene mold and dried at 50°C for 36 hours. After complete evaporation of moisture, the film was peeled off the mold to obtain the film, which was named ZPT0 / WPU, ZPT1 / WPU, and ZPT / WPU, respectively, according to the naming conventions of the examples or comparative examples.

[0074] The tensile strength and elongation at break of the ZPT / WPU composite film were tested using an electronic universal testing machine. The sample size was 75 mm × 12.5 mm × 0.3 mm, and the tensile rate was 50.0 mm / min. Five sets of tests were performed on each sample in parallel, and the morphology of the fracture surface of the samples was observed. The results are as follows: Figure 16-17 As shown.

[0075] Figure 16 This is a graph showing the mechanical properties of the ZPT / WPU composite film. Figure 17 This is a morphological image of the fracture surface of a ZPT / WPU composite film sample. (Observation) Figure 16It is known that the tensile strength of pure WPU is 7.9 MPa and the elongation at break is 640%; the tensile strength of ZPT0 / WPU is 7.4 MPa and the elongation at break is 550%, which are 6.3% and 14.1% lower than that of pure WPU, respectively; the tensile strength of ZPT1 / WPU of this invention is 7.5 MPa and the elongation at break is 540%, which are 5.1% and 15.6% lower than that of pure WPU, respectively; the tensile strength of ZTP / WPU prepared by the physical mixing method is 7.4 MPa and the elongation at break is 530%, which are 6.3% and 17.2% lower than that of pure WPU, respectively. Under low load conditions with a total filler content not exceeding 22 wt.%, the elongation at break of all composite films remains above 500%, exhibiting excellent flexible deformation capability. Among them, ZPT1 / WPU has the best mechanical property retention rate, and its tensile strength is slightly higher than that of ZPT0 / WPU containing only binary core-shell fillers, and significantly better than that of ZTP / WPU obtained by the physical mixing method. Cross-sectional morphology and interface compatibility analysis ( Figure 17 Further analysis shows that the pure WPU fracture surface is smooth and flat, without obvious defects, exhibiting typical ductile fracture characteristics; the ZPT0 / WPU fracture surface shows a few fine wrinkles, indicating that there is a certain interfacial interaction between the T-ZnO@PANI core-shell filler and the WPU matrix, but local stress concentration is still present; the ZPT1 / WPU fracture surface of this invention is dense and uniform, and no obvious filler agglomerates and interface debonding phenomenon were observed, indicating that the T-ZnO@PANI / Ti3C2T constructed by interfacial sequence control... x The composite filler exhibits excellent dispersibility in the WPU matrix, primarily due to the enhanced hydrogen bonds formed between the PANI shell and the WPU molecular chains, which strengthen the filler-matrix interfacial interaction. Simultaneously, the high aspect ratio of the two-dimensional Ti3C2T... x Nanosheets can effectively transfer applied stress and alleviate stress concentration; however, the cross-section of ZTP / WPU shows a small number of micropores and filler agglomerates, and the interfacial bonding is relatively loose, which is the main reason why its mechanical properties are slightly lower than those of ZPT1 / WPU.

[0076] Example 14 According to the formula, T-ZnO@PANI accounts for 20 wt% of natural rubber (NR) and Ti3C2T xMXene was added at a ratio of 1 wt% of natural rubber. The ZPT composite material obtained in Example 1 or the comparative example was mixed with natural rubber on a two-roll mill at room temperature for 15 min to ensure uniform dispersion of the filler in the rubber matrix. Subsequently, sulfur (2 wt% of rubber mass), zinc oxide (5 wt% of rubber mass), and stearic acid (2 wt% of rubber mass) were added to the mixture, and mixing continued for 5 min until homogeneous. The resulting mixture was then hot-pressed and vulcanized on a flat vulcanizing machine at 150°C and 15 MPa for 15 min. After cooling, a flexible electromagnetic shielding composite film was obtained. Following the naming convention of the examples or comparative examples, these films were named ZPT0 / NR and ZPT1 / NR, respectively. The morphology of the fracture surface of the samples was observed, and their electromagnetic wave absorption performance was evaluated. The results are as follows: Figure 18-19 As shown.

[0077] Figure 18 The image shows a SEM image of the liquid nitrogen brittle fracture surface of the ZPT / NR composite material. As can be seen from Figure (a), ZPT... 0 / The NR cross-section exhibits an irregular torn morphology, and obvious filler agglomerates can be observed in localized areas. 1 wt.% Ti3C2T was introduced. x The ZPT1 / NR composite material (Figure b) exhibits a dense and uniform fracture surface with no obvious large-sized pores or filler agglomeration. The surface is covered with numerous wrinkles and tear ridges, displaying typical ductile fracture characteristics. The fracture morphology suggests that the introduction of two-dimensional MXene nanosheets improved the dispersibility and interfacial bonding of the filler in the NR matrix, inhibiting both the agglomeration of T-ZnO@PANI particles and the formation of Ti3C2T... x The abundant functional groups (-OH, -O, -F) on the surface can interact with NR molecular chains, enhancing interfacial bonding strength and improving stress transfer efficiency. This optimization of the microstructure lays the foundation for improving the mechanical properties of composite materials. Figure 19 This is a graph showing the electromagnetic wave absorption performance of the ZPT / NR composite material. For the ZPT0 / NR composite material (ac), it exhibits extremely strong electromagnetic wave attenuation capability at a matched thickness of 4.19 mm. min Reaching -50.98 dB, corresponding to an electromagnetic wave absorption rate exceeding 99.999%. The EAB of the composite material. max It has a current of 1.7 GHz, covering a single continuous frequency band of 9.15-10.85 GHz. At a thickness of 1 mm, RL min >-10 dB, no significant effective absorption. For the ZPT1 / NR composite (df), the optimal matching thickness is significantly reduced to 2.9 mm, corresponding to RL min The EAB is -40.78 dB. Notably, at an ultrathin thickness of 1 mm, the EAB of ZPT1 / NR is... maxIt can reach 2.3 GHz, covering two discontinuous frequency bands of 8.2-10.35 GHz and 11.75-12.2 GHz, achieving almost effective coverage at both ends of the X-band.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A T-ZnO@PANI / Ti3C2T x The method for preparing electromagnetic shielding materials is characterized by, Includes the following steps: To Ti3C2T x The zinc oxide@polyaniline composite material is added to the dispersion, ultrasonically dispersed, and then freeze-dried to obtain the final product.

2. The T-ZnO@PANI / Ti3C2T according to claim 1 x The method for preparing electromagnetic shielding materials is characterized by, The zinc oxide@polyaniline, Ti3C2T x The mass ratio is 1:(0.025-0.1); the Ti3C2T x The concentration of the dispersion is 0.5-2 mg / mL.

3. The T-ZnO@PANI / Ti3C2T according to claim 2 x The method for preparing electromagnetic shielding materials is characterized by, The preparation method of the zinc oxide@polyaniline composite material is as follows: Add the dopant and stabilizer to water to obtain a mixed solution; add aniline monomer to the mixed solution, then add an oxidant solution to carry out a first polymerization reaction, then add a tetra-needle zinc oxide dispersion to carry out a second polymerization reaction, and after purification, the product is obtained.

4. The T-ZnO@PANI / Ti3C2T according to claim 3 x The method for preparing electromagnetic shielding materials is characterized by, The mass ratio of the aniline monomer, dopant, stabilizer, oxidant, and tetraneedle zinc oxide is 0.465:(2-2.2):(0.45-0.55):(1.1-1.2):(1.3-1.5); the dopant is dodecylbenzenesulfonic acid; the stabilizer is polyvinylpyrrolidone; and the oxidant is ammonium persulfate.

5. The T-ZnO@PANI / Ti3C2T according to claim 3 x The method for preparing electromagnetic shielding materials is characterized by, The concentration of the stabilizer in the mixed solution is 0.01-0.02 g / mL; the concentration of the oxidant solution is 0.2-0.3 g / mL; and the concentration of the tetraneedle-shaped zinc oxide dispersion is 0.09-0.1 g / mL.

6. The T-ZnO@PANI / Ti3C2T according to claim 3 x The method for preparing electromagnetic shielding materials is characterized by, The temperature of the first polymerization reaction is 0-5℃ and the time is 1.5-2.5 h; the temperature of the second polymerization reaction is 0-5℃ and the time is 1-2 h; the ultrasonic dispersion time is 10-20 min.

7. A T-ZnO@PANI / Ti3C2T x Electromagnetic shielding material, characterized in that, It is prepared by the preparation method according to any one of claims 1-6.

8. The T-ZnO@PANI / Ti3C2T as described in claim 7 x The application of electromagnetic shielding materials is characterized by, Used to manufacture flexible electromagnetic protection products.

9. The T-ZnO@PANI / Ti3C2T according to claim 8 x The application of electromagnetic shielding materials is characterized by, The flexible electromagnetic protection product is a flexible absorbing film or absorbing coating; the substrate of the flexible electromagnetic protection product is water-based polyurethane, rubber or paraffin.

10. The T-ZnO@PANI / Ti3C2T according to claim 9 x The application of electromagnetic shielding materials is characterized by, In flexible electromagnetic protection products, Ti3C2T x The nanosheets account for 0.5-1.5 wt% of the matrix.

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