Preparation method of magnetoelectric coupling gel for absorbing electromagnetic waves under dynamic deformation

Abstract

The invention provides a preparation method of magnetoelectric coupling gel for absorbing electromagnetic waves under dynamic deformation. The method comprises the following steps: preparing Cu2O octahedral particles, Cu2O coated CuS, hollow Cu2O coated CuS particles and Ag / CuO coated CuS particles, and preparing the magnetoelectric coupling gel. The invention further provides application. The magnetoelectric coupling gel for absorbing the electromagnetic waves under the dynamic deformation is used for preparing an electromagnetic protection product. According to the invention, a composite gel system with a reconfigurable'magnetic-electric-dielectric 'multidimensional coupling network can be constructed, broadband efficient wave absorption in a static state is realized, meanwhile, the problems of performance maintenance and regulation in a dynamic deformation process are solved, and the material can still keep stable electromagnetic wave absorption performance under dynamic deformation such as stretching and the like; and a material foundation is laid for practical and high-performance electromagnetic protection products.

Description

Technical Field

[0001] This invention belongs to the field of functional materials and electromagnetic wave absorption technology, specifically relating to a method for preparing and applying a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation. Background Technology

[0002] With the rapid popularization of 5G mobile communication, the Internet of Things (IoT), and artificial intelligence (AI) technologies, human society is entering a highly interconnected and ubiquitous intelligent era. Simultaneously, the electromagnetic environment is becoming increasingly complex and intense. From communication base stations and mobile terminals to various electronic devices, the density and intensity of electromagnetic signals in space have significantly increased, forming broadband, high-intensity complex electromagnetic fields. This environment may not only interfere with the normal operation of precision electronic equipment and lead to a decline in communication quality, but may also have potential cumulative effects on human health. Therefore, developing high-performance electromagnetic wave absorbing materials to achieve effective electromagnetic protection has become an urgent need to ensure the reliability of electronic systems, information security, and human health.

[0003] At the other end of the technology application spectrum, flexible electronics and wearable devices are developing rapidly. From health monitoring bracelets and flexible displays to electronic skin and implantable medical devices, these devices need to fit closely to the human body or move with mechanical structures, thus constantly facing dynamic deformations such as stretching, bending, and folding. This places unprecedented demands on the functional materials integrated within them: materials must not only possess excellent performance under static conditions, but also maintain functional stability and reliability during repeated and significant deformations. The traditional evaluation system centered on "static performance" is no longer adequate to meet the stringent requirements of "dynamic robustness" in the field of flexible wearables.

[0004] This contradiction is particularly prominent in the field of electromagnetic wave absorbing materials. An ideal flexible absorbing material should simultaneously meet two major objectives: first, to achieve efficient absorption over a wide frequency range; and second, to maintain stable absorption performance during deformation. However, most existing material systems have significant shortcomings in this regard. Many materials, while performing well in a static state, are prone to internal structural damage or disordered reorganization once subjected to stretching or complex deformation, leading to electromagnetic parameter mismatch, deterioration of impedance conditions, and ultimately a significant decrease or even failure of absorption performance. This phenomenon of "deformation equals failure" severely limits the application of flexible absorbing materials in real-world dynamic scenarios.

[0005] Therefore, current research focus has shifted from simply improving static performance to constructing a new generation of flexible materials that combine efficient absorption with deformation stability. This requires materials to possess reconfigurable and adaptive structural properties at the microscopic level, and to maintain electromagnetic functionality for a long time during deformation at the macroscopic level. Solving this challenge is crucial for advancing flexible microwave absorbing materials from the laboratory to practical applications, and is also a key prerequisite for their widespread application in wearable devices, smart skins, and adaptive stealth systems. This invention aims to provide an innovative material solution that can stably maintain efficient broadband microwave absorption performance under dynamic deformation.

[0006] Traditional electromagnetic wave absorbing / shielding materials are mainly rigid materials such as ferrites, metal alloys, and carbon-based composites. To meet the requirements for flexibility, researchers have attempted to introduce functional fillers such as carbon nanotubes, graphene, and magnetic nanoparticles into flexible polymer matrices such as silicone rubber, polyurethane, and hydrogels, developing a series of flexible composite materials. Current research mostly focuses on testing the static properties of materials under a "fixed deformation state," and has not yet established an active "deformation-performance" control system starting from the material design source.

[0007] Disadvantages of existing technology: 1. Defects of traditional rigid materials: Ferrites, metal alloys, and carbon-based composite materials generally suffer from high rigidity and brittleness, making them difficult to adapt to dynamic deformation requirements such as bending, stretching, and twisting. Under dynamic deformation, the microstructure is prone to cracks or even fractures, leading to the destruction of the conductive / magnetic loss network and a sharp decline or even complete failure of electromagnetic performance, thus failing to meet the requirements of flexible and wearable applications.

[0008] 2. Existing core challenges in flexible materials: ① Multi-mechanism failure under deformation: The realization of high-performance microwave absorption efficiency is highly dependent on the synergistic coupling effect of multiple physical field loss mechanisms such as dielectric polarization, magnetic loss, and conductive loss. During dynamic deformation, the spatial configuration of each functional phase undergoes disordered evolution and phase separation, causing the pre-constructed multi-dimensional loss coupling network to deconstruct, and the matching relationship between various loss mechanisms to become unbalanced, ultimately resulting in a cliff-like decrease in the microwave absorption performance of the material under deformation conditions.

[0009] ② Dynamic impedance matching detuning: The prerequisite for efficient absorption of electromagnetic waves is good impedance matching, which allows electromagnetic waves to penetrate the material to the maximum extent possible rather than being reflected. When existing flexible materials undergo deformation, their equivalent complex permittivity and complex permeability often change in a non-coordinated manner, leading to impedance matching detuning over a wide frequency band, a significant increase in reflection loss (RL), and a narrowing or even disappearance of the effective absorption bandwidth (EAB).

[0010] ③ Lack of proactive control strategies: Current research mostly focuses on testing the static properties of materials under a "fixed deformation state," and has not yet established a theoretical system and methodology that starts from the material design stage and uses proactive "deformation engineering" to predict, control, and stabilize the electromagnetic response. The performance changes of materials under deformation are passive and uncontrollable.

[0011] 3. Overall performance shortcomings: Most flexible absorbing materials are "flexible but not strong" (can only be bent but not stretched) or "fail upon deformation," falling far short of the requirement for "dynamic applicability." They cannot maintain the continuity and stability of the magnetoelectric network structure under various dynamic deformation conditions, making it difficult to ensure the long-term effectiveness of the synergistic effect of multiple loss mechanisms. Summary of the Invention

[0012] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing and applying a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation. This method can construct a composite gel system with a reconfigurable "magnetic-electrical-dielectric" multidimensional coupling network, achieving broadband and efficient wave absorption under static conditions. At the same time, it solves the problem of performance maintenance and control during dynamic deformation, ensuring that the material can maintain stable electromagnetic wave absorption performance under dynamic deformation such as stretching, thus laying a material foundation for practical and high-performance electromagnetic protection products.

[0013] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation, the method being as follows: Preparation of S1 and Cu2O octahedral particles: CuCl2·2H2O and polyvinylpyrrolidone were added to deionized water and stirred for 30-40 minutes. Then, NaOH aqueous solution was added dropwise. After stirring for 30-40 minutes at 55-65°C, ascorbic acid aqueous solution was added dropwise. The mixture was then reacted at 55-65°C for 3-4 hours. The resulting precipitate was filtered, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain Cu2O octahedral particles. Preparation of S2 and Cu2O@CuS: The Cu2O octahedral particles obtained in S1 were dispersed in deionized water, ultrasonically treated, and then Na2S aqueous solution was added dropwise. After stirring for 30 min to 40 min, the precipitate was collected by vacuum filtration. The precipitate was washed with deionized water and anhydrous ethanol in sequence, and then dried under vacuum to obtain octahedral particles with a core-shell structure, denoted as Cu2O@CuS. S3. Preparation of hollow Cu2O@CuS particles: The Cu2O@CuS obtained in S2 was dispersed in an ethanol aqueous solution. After ultrasonic dispersion, Na2S2O3 aqueous solution was added and stirred for 30 min to 40 min. The precipitate was collected by vacuum filtration. The precipitate was washed with deionized water and anhydrous ethanol in sequence and dried under vacuum to obtain hollow Cu2O@CuS particles, denoted as H-Cu2O@CuS. Preparation of S4 and Ag / CuO@CuS particles: The H-Cu2O@CuS obtained in S3 was dispersed in deionized water, ultrasonically treated, and then AgNO3 aqueous solution and ascorbic acid aqueous solution were added. The mixture was stirred at room temperature for 30 min to 40 min, and the precipitate was collected by vacuum filtration. The precipitate was washed with deionized water and anhydrous ethanol in sequence, and then dried under vacuum to obtain Ag / CuO@CuS particles, denoted as ACS. S5. Preparation of magnetoelectric coupling gel: After uniformly mixing acrylamide monomer, acrylic acid monomer, crosslinking agent N,N'-methylenebisacrylamide, and photoinitiator I2959, the mixture was dissolved in 1-ethyl-3-methylimidazolium sulfate ionic liquid. Then, Ag / CuO@CuS particles obtained from graphene oxide, multi-walled carbon nanotubes, Fe3O4, and S4 were added. After stirring in an ice bath, the mixture was ultrasonically treated to obtain a prepolymer solution, which was transferred to a polytetrafluoroethylene mold. A glass plate was then placed on the polytetrafluoroethylene mold, and free radical polymerization was initiated under a 365 nm ultraviolet lamp for 30 min to obtain a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation.

[0014] Preferably, the ratio of CuCl2·2H2O, polyvinylpyrrolidone, deionized water, NaOH aqueous solution, and ascorbic acid aqueous solution in S1 is (0.686~0.8) g : (13.32~15) g : 400 mL : 40 mL : 40 mL; the concentration of the NaOH aqueous solution is 2.0 mol / L; and the concentration of the ascorbic acid aqueous solution is 0.6 mol / L.

[0015] Preferably, the number of times deionized water is washed in S1 to S4 is 3 to 4 times, and the number of times anhydrous ethanol is washed is 3 to 4 times; the vacuum drying conditions in S1 to S4 are 60℃ for 4 to 6 hours.

[0016] Preferably, the ultrasound conditions in S2 to S4 are 400~500W for 10min~20min.

[0017] Preferably, the ratio of Cu2O octahedral particles, deionized water, and Na2S aqueous solution in S2 is (0.151~0.16) g: 200 mL: 100 mL; and the concentration of the Na2S aqueous solution is 2.5 mmol / L.

[0018] Preferably, the ratio of Cu2O@CuS, ethanol aqueous solution, and Na2S2O3 aqueous solution in S3 is (0.081~0.09) g: 200 mL: 80 mL; the volume fraction of the ethanol aqueous solution is 50%; and the concentration of the Na2S2O3 aqueous solution is 1.0 mol / L.

[0019] Preferably, the ratio of H-Cu2O@CuS, deionized water, AgNO3 aqueous solution and ascorbic acid aqueous solution in S4 is (0.02~0.03) g: 100 mL: 10 mL: 10 mL; the concentration of AgNO3 aqueous solution is 0.3 mol / L, and the concentration of ascorbic acid aqueous solution is 0.1 mol / L.

[0020] Preferably, the ratio of the monomer acrylamide, monomer acrylic acid, crosslinking agent N,N'-methylenebisacrylamide, photoinitiator I2959, 1-ethyl-3-methylimidazolium sulfate ethyl ionic liquid, graphene oxide, multi-walled carbon nanotubes, Fe3O4 and Ag / CuO@CuS particles in S5 is 4g:2g:30mg:20mg:10mL:0.01g:0.01g:0.02g.

[0021] Preferably, the stirring conditions in S5 are: rotation speed 800 r / min, 5 min to 10 min; the ultrasonic treatment conditions in S5 are: working time 10 min; working cycle 6 s, interval 3 s, power 800 W to 1000 W.

[0022] This invention also provides the application of the magnetoelectric coupling gel prepared by the above preparation method for absorbing electromagnetic waves under dynamic deformation, wherein the magnetoelectric coupling gel for absorbing electromagnetic waves under dynamic deformation is used to prepare electromagnetic protection products.

[0023] Compared with the prior art, the present invention has the following advantages: 1. The static absorption performance of the magnetoelectric coupling gel prepared by this invention for electromagnetic wave absorption under dynamic deformation: it has excellent broadband absorption and high loss synergy.

[0024] This magnetoelectric coupling gel, designed for electromagnetic wave absorption under dynamic deformation, exhibits superior electromagnetic wave absorption capabilities under static conditions. The material is based on a P(AM-co-AA) polymer network, combined with a GO / MWCNTs three-dimensional conductive framework, Fe3O4 magnetic nanoparticles, and an ACS dielectric nanoparticle array to construct a continuous and stable multidimensional magnetoelectric coupling network. This structure achieves efficient synergy between conductive loss, magnetic loss, and interfacial polarization loss, demonstrating excellent static wave absorption and broadband stealth potential.

[0025] 2. Dynamic wave absorption response of the magnetoelectric coupling gel prepared by the present invention for electromagnetic wave absorption under dynamic deformation: deformation adaptive matching and stability maintenance.

[0026] During dynamic stretching, the material exhibits excellent deformation tolerance and performance stability. The introduction of ionic liquid enhances the dynamic reconfigurability of the network, enabling conductive pathways and magnetic particles to adaptively reconfigure under strain. This ensures that multiple loss mechanisms continue to work synergistically during deformation, overcoming the bottleneck of traditional flexible microwave absorbing materials where "deformation leads to failure."

[0027] 3. The structural response mechanism of the magnetoelectric coupling gel prepared by this invention for electromagnetic wave absorption under dynamic deformation: the performance evolution is driven by a reconfigurable magnetoelectric coupling network.

[0028] The excellent dynamic and static properties of the magnetoelectric coupling gel prepared in this invention for electromagnetic wave absorption under dynamic deformation stem from its reconfigurable multidimensional magnetoelectric coupling network. During stretching, the polymer chains drive the slippage of the GO layer and the tilting of MWCNTs, while Fe3O4 and ACS particles undergo distribution and recombination, forming a dynamically reconfigured conductive and magnetic array. This adaptive structural mechanism directly regulates impedance matching and electromagnetic parameters, ensuring that the material maintains macroscopic structural integrity and electromagnetic function continuity under dynamic conditions, providing a new design path for flexible electromagnetic control materials.

[0029] 4. Material Structure Innovation (Reconfigurable Magnetoelectric Coupling Network): Unlike the simple mechanical blending of functional fillers in flexible matrices in existing technologies, this invention constructs a three-dimensional interconnected, stress-responsive "magnetic-electrical-dielectric" multidimensional coupling network in situ by multi-level synergistic dispersion and assembly of specific one-dimensional / two-dimensional conductive frameworks (multi-walled carbon nanotubes and graphene oxide), magnetic nanoparticles (Fe3O4), and dielectric nanoparticle arrays (Ag / CuO@CuS) in an ionic liquid prepolymer system. This network exhibits structural continuity and reconfigurability within the polymer gel matrix, providing a microstructural basis for maintaining a stable electromagnetic loss synergistic effect under dynamic deformation.

[0030] 5. Innovative Performance Mechanism (Deformation-Adaptive Impedance Matching): Unlike existing flexible absorbing materials that suffer from impedance matching detuning under deformation, this invention utilizes the aforementioned special network structure to enable coordinated and directional rearrangement of the internal conductive pathways, magnetic particles, and dielectric polarization units when the material is stretched. This drives the co-evolution of the material's equivalent complex permittivity and complex permeability. This inherent "deformation-electromagnetic parameter" coupling mechanism can dynamically maintain good impedance matching conditions over a wide frequency range, effectively overcoming the problems of increased reflectivity and narrowed absorption bandwidth caused by deformation.

[0031] 6. Comprehensive Performance Innovation (Broadband High-Efficiency Wave Absorption under Dynamic Deformation): Unlike most "pseudo-flexible" materials that only exhibit static bending properties or whose performance degrades significantly under small strain, the magnetoelectric coupling gel prepared in this invention for electromagnetic wave absorption under dynamic deformation demonstrates excellent dynamic applicability. Experiments show that this material can maintain an ultra-high effective absorption bandwidth even after experiencing tensile strains of up to 50%, and its optimal absorption thickness can be adaptively adjusted with deformation. This achieves a performance leap from "static flexibility" to "dynamic applicability."

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 This invention describes the preparation process of a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation.

[0034] Figure 2 The images shown are: (a) SEM image; (b) TEM image; (c) HR-TEM image; (d) energy-dispersive X-ray spectroscopy (EDS) image; and (e) selected area electron diffraction (SAED) image of Cu2O@CuS prepared in step S2 of Example 1 of this invention.

[0035] Figure 3 The images shown are: (a) SEM image; (b) TEM image; (c) HR-TEM image; (d) energy dispersive X-ray spectroscopy (EDS) image; and (e) selected area electron diffraction (SAED) image of the hollow Cu2O@CuS prepared in step S3 of Example 1 of this invention.

[0036] Figure 4 The images shown are: (a) SEM image; (b) TEM image; (c) element ratio in the grid area; (d) energy-dispersive X-ray spectroscopy (EDS) image; and (e) selected area electron diffraction (SAED) image of Ag / CuO@CuS prepared in step S4 of Example 1 of this invention.

[0037] Figure 5 In Embodiment 1 of the present invention, step S5 (a, b) is a SEM image before polymerization, where a and b are images from different angles; (c) is a cross-sectional SEM image of the polymerized magnetoelectric coupling gel.

[0038] Figure 6 These are the absorption performance diagrams of the magnetoelectric coupling gel prepared in Example 1 of this invention for electromagnetic wave absorption under dynamic deformation in the unstretched state. Among them, (a) is the three-dimensional-RL diagram; (b) is the two-dimensional-RL diagram; and (c) is the impedance matching diagram.

[0039] Figure 7This is a graph showing the absorption performance of the magnetoelectric coupling gel prepared in Example 1 of this invention for electromagnetic wave absorption under dynamic deformation in the X-band (8.2-12.4 GHz) under unstretched (first row) and 50% stretched (second row) conditions. (a1) and (a2) are two-dimensional -RL plots for unstretched and 50% stretched conditions, respectively; (b1) and (b2) are impedance matching plots for unstretched and 50% stretched conditions, respectively; and (c1) and (c2) are three-dimensional RCS simulation plots for unstretched and 50% stretched conditions, respectively. Detailed Implementation

[0040] Example 1 The preparation method of the magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation in this embodiment is as follows: Figure 1 The method is as follows: Preparation of S1 and Cu2O octahedral particles: 0.686 g CuCl2·2H2O and 13.32 g polyvinylpyrrolidone (PVP) were added to 400 mL of deionized water and stirred for 30 min to obtain a dark brown solution. Then, 40 mL of 2.0 mol / L NaOH aqueous solution was added dropwise. After stirring at 55 °C for 30 min, 40 mL of 0.6 mol / L ascorbic acid aqueous solution was added dropwise. After reacting at 55 °C for 3 h, the precipitate was filtered and washed three times with deionized water and three times with anhydrous ethanol. After vacuum drying at 60 °C for 4 h, Cu2O octahedral particles were obtained. Preparation of S2 and Cu2O@CuS: 0.151 g of Cu2O octahedral particles obtained from S1 were dispersed in 200 mL of deionized water. After ultrasonic treatment for 10 min using a cell disruptor at 400 W, 100 mL of 2.5 mmol / L Na2S aqueous solution was added dropwise to induce a sulfidation reaction in the Cu2O template. After stirring for 30 min, the precipitate was collected by vacuum filtration. The precipitate was washed three times with deionized water and three times with anhydrous ethanol. After vacuum drying at 60 °C for 4 h, octahedral particles with a core-shell structure were obtained, denoted as Cu2O@CuS. like Figure 2 As shown, Figure 2 (a) is a SEM image of the prepared Cu2O@CuS, in which the sheet-like CuS is densely and uniformly inserted into the Cu2O surface; Figure 2 (b) is a TEM image, which clearly shows the core-shell structure of Cu2O@CuS; Figure 2 (c) is an HR-TEM image, and the lattice fringe width indicates that it is CuS; Figure 2(d) Energy dispersive X-ray spectroscopy (EDS) diagram, the elemental distribution of which indicates that the nanoparticles have a core-shell structure; Figure 2 (e) is a selected area electron diffraction (SAED) pattern, where the 105 and 220 crystal planes represent Cu2O and CuS, respectively, further proving the crystal structures of Cu2O and CuS.

[0041] S3. Preparation of hollow Cu2O@CuS particles: 0.081 g of Cu2O@CuS obtained from S2 was dispersed in 200 mL of 50% ethanol aqueous solution. After ultrasonic dispersion for 10 min at 400 W, 80 mL of 1.0 mol / L Na2S2O3 aqueous solution was added and stirred for 30 min. The precipitate was collected by vacuum filtration. The precipitate was washed three times with deionized water and three times with anhydrous ethanol. After vacuum drying at 60 °C for 4 h, hollow Cu2O@CuS particles were obtained, denoted as H-Cu2O@CuS. The thin Cu2O layer retained inside the CuS shell provided conditions for the uniform introduction of Ag particles. like Figure 3 As shown, Figure 3 (a) is a SEM image of the prepared hollow Cu2O@CuS. The sheet-like CuS is densely and uniformly inserted into the Cu2O surface, and the structure is complete. Figure 3 (b) is a TEM image, which clearly shows the hollow structure; Figure 3 (c) is an HR-TEM image, and the lattice fringe width indicates that it is CuS; Figure 3 (d) is the energy dispersive X-ray spectroscopy (EDS) diagram, whose elemental distribution indicates that the nanoparticles have a hollow structure and the CuO thin layer can be clearly seen; Figure 3 (e) is selected area electron diffraction (SAED), where the 111, 220 and 103, 110 crystal planes represent Cu2O and CuS, respectively, further proving the crystal structures of Cu2O and CuS.

[0042] Preparation of S4 and Ag / CuO@CuS particles: H-Cu2O@CuS obtained from 0.02g of S3 was dispersed in 100mL of deionized water and ultrasonically treated for 10min at 400W. Then, 10mL of 0.3mol / L AgNO3 aqueous solution and 10mL of 0.1mol / L ascorbic acid aqueous solution were added. The mixture was stirred at room temperature for 30min, and the precipitate was collected by vacuum filtration. The precipitate was washed three times with deionized water and three times with anhydrous ethanol. After vacuum drying at 60℃ for 4h, Ag / CuO@CuS particles with a particle size of 1.2μm were obtained, denoted as ACS. like Figure 4As shown, Figure 4 (a) is a SEM image of the prepared ACS. Many nanosheets appear in the middle of the particles. These nanosheets connect the individual particles together and maintain an appropriate spacing between the particles. The particles still maintain a regular octahedron. Figure 4 (b) is a TEM image, which clearly shows the hollow structure and nanosheets; Figure 4 (c) represents the elemental ratio, indicating that Ag is the main component in the nanosheets; Figure 4 (d) is the energy dispersive X-ray spectroscopy (EDS) diagram, whose elemental distribution indicates that the nanoparticles have a hollow structure and a nanosheet structure of Ag. Figure 4 (e) shows selected area electron diffraction (SAED), where the 002, 101 and 111 crystal planes represent CuO, CuS and Ag, respectively, further proving the crystal structures of CuO, CuS and Ag.

[0043] S5. Preparation of magnetoelectric coupling gel: 4g of monomeric acrylamide (AM), 2g of monomeric acrylic acid (AA), 30mg of crosslinking agent N,N'-methylenebisacrylamide (MBA), and 20mg of photoinitiator I2959 were mixed thoroughly and then dissolved in 10mL of 1-ethyl-3-methylimidazolium sulfate ([EMI]). + [ES] - In an ionic liquid, 0.01 g of graphene oxide (GO), 0.01 g of multi-walled carbon nanotubes (MWCNTs), 0.01 g of Fe3O4, and 0.02 g of Ag / CuO@CuS particles obtained from S4 were added. The mixture was stirred for 5 min in an ice bath at a speed of 800 r / min, followed by ultrasonic treatment for 10 min (6 s working cycle, 3 s interval, 800 W power) to obtain a prepolymer solution. This solution was then transferred to a polytetrafluoroethylene (PTFE) mold with a depth of 1 mm. A glass plate was then placed over the PTFE mold to ensure a smooth surface. Free radical polymerization was initiated under a 365 nm UV lamp for 30 min to obtain a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation.

[0044] In this embodiment, monomers acrylamide (AM) and acrylic acid (AA) constitute a P(AM-co-AA) ionogel network, which serves as a polymer matrix to provide stretchability and structural support. A three-dimensional conductive network constructed from graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) serves as a conductive framework. Fe3O4 nanoparticles are uniformly distributed in the conductive framework and serve as a magnetic component. Ag / CuO@CuS (ACS) nanoparticle array enhances interfacial polarization and serves as a dielectric component; Ionic liquids ([EMI]) +[ES] - It serves as a medium for conductivity and polarization regulation.

[0045] The magnetoelectric coupling gel structure for electromagnetic wave absorption under dynamic deformation in this embodiment has the following characteristics: GO and MWCNTs form a three-dimensional conductive network, and Fe3O4 and ACS are uniformly distributed on its surface to construct a "magnetic-electrical-dielectric" multidimensional coupling channel; The polymer network provides elastic support, while the ionic liquid acts as a dynamic medium, synergistically regulating conductivity and polarization behavior. During stretching, the network undergoes controllable reconstruction, and the magnetic particles and conductive pathways are redistributed, achieving adaptive impedance matching under deformation.

[0046] like Figure 5 As shown, Figure 5 (a, b) are SEM images of GO, MWCNTs, ACS, Fe3O4, and Fe3O4 before polymerization from different angles. Fe3O4, ACS, and MWCNTs are uniformly dispersed on the surface of GO, and some particles are encapsulated inside GO. The dispersion of each component and the formation of a network structure are shown. Figure 5 (c) is a SEM cross-sectional image of the polymerized magnetoelectric coupling gel, showing a clear network structure with high connectivity between pores, forming a three-dimensional conductive network. The red and blue marked areas represent the uniform distribution of Fe3O4 nanoparticles and ACS nanoparticles, while the purple marked areas represent nanosheets in ACS, constructing a "magnetic-electrical-dielectric" multidimensional coupling channel. The smooth pore walls are ionic liquids stably retained in the network structure, which interact with the P(AM-co-AA) chains. This demonstrates that the ionic liquid acts as a dynamic medium, providing conditions for strain, while the polymer network provides elastic support for this.

[0047] (i) Static performance test of the magnetoelectric coupling gel prepared in this embodiment for electromagnetic wave absorption under dynamic deformation.

[0048] In its unstretched state, the electromagnetic coupling gel prepared in this embodiment for electromagnetic wave absorption under dynamic deformation exhibits the following absorption properties: Figure 6 As shown, at a thickness of 2.9 mm, the material achieves a minimum reflection loss of -43.8 dB, meaning that over 99.99% of the incident electromagnetic waves at this frequency are absorbed. Figure 6 (a) With a thickness of 3.2mm, the EAB value reached 9.44 GHz, covering the commonly used radar frequency band of 8.56-18 GHz, demonstrating potential for practical application. Figure 6 (b) Furthermore, the combined effect of the ionic liquid and the electromagnetic components results in excellent impedance matching performance of the composite gel. Figure 6 (c) Finally, a composite gel with good static absorption properties was formed.

[0049] The magnetoelectric coupling gel prepared in this embodiment for electromagnetic wave absorption under dynamic deformation exhibits excellent broadband absorption and high loss synergy.

[0050] This magnetoelectric coupling gel, designed for electromagnetic wave absorption under dynamic deformation, exhibits superior electromagnetic wave absorption capabilities under static conditions. The material is based on a P(AM-co-AA) polymer network, combined with a GO / MWCNTs three-dimensional conductive framework, Fe3O4 magnetic nanoparticles, and an ACS dielectric nanoparticle array to construct a continuous and stable multidimensional magnetoelectric coupling network. This structure achieves highly efficient synergy between conductive loss, magnetic loss, and interfacial polarization loss, demonstrating strong comprehensive absorption performance in an ultra-wideband frequency range of 2-18 GHz. Furthermore, it achieves a minimum reflection loss of -43.8 dB at 6.68 GHz, showcasing excellent static absorption and broadband stealth potential.

[0051] (II) Dynamic performance test of the magnetoelectric coupling gel prepared in this embodiment for electromagnetic wave absorption under dynamic deformation - stretching 50%.

[0052] A tensile strain of 50% was applied to the magnetoelectric coupling gel prepared in this embodiment for electromagnetic wave absorption under dynamic deformation. Figure 7 Test results show that the material maintains excellent microwave absorption performance even under deformation, and the optimal absorption thickness of the material adaptively adjusts with tensile strain: its effective electromagnetic wave absorption region covers the entire X-band (8.4-12.2 GHz) with a thickness of about 3 mm, and the minimum reflection loss in this region is -19.9 dB. Figure 7 (a1). When the composite gel is stretched to 50%, the effective electromagnetic wave absorption region thickness is reduced to about 2 mm, and the corresponding minimum reflection loss is reduced to -12.45 dB, while still maintaining the above-mentioned broadband absorption performance. Figure 7 (a2). Comparison of the two-dimensional RL plot and impedance matching plot revealed that the impedance matching region of the original length composite gel basically coincides with the effective absorption region. Figure 7 (b1), as the elongation reaches 50%, the maximum impedance matching value is 0.66 ( Figure 7 (b2). Radar cross section (RCS) simulations further demonstrate that, with the adjusted thickness, the stretched material still achieves a reduction value below -10 dB over a wide incident angle range, proving its effectiveness and stability in real-world dynamic scenarios. Figure 7 (c1, c2). This result verifies the key contribution of the synergistic effect of the ionic liquid medium and the reconfigurable coupled network to maintaining performance under deformation.

[0053] The dynamic absorption response of the magnetoelectric coupling gel prepared in this embodiment for electromagnetic wave absorption under dynamic deformation: deformation adaptive matching and stability maintenance.

[0054] During dynamic stretching, the material exhibits excellent deformation tolerance and performance stability. Even with a stretch rate of 50%, its effective absorption bandwidth still covers the entire X-band, and with the thickness reduced to 2 mm, the minimum reflection loss remains at -12.45 dB. The introduction of ionic liquid enhances the dynamic reconfigurability of the network, enabling adaptive reconstruction of conductive pathways and magnetic particles under strain. This ensures the continuous synergy of multiple loss mechanisms during deformation, overcoming the bottleneck of traditional flexible microwave absorbing materials where "deformation equals failure."

[0055] The structural response mechanism of the magnetoelectric coupling gel prepared in this embodiment for electromagnetic wave absorption under dynamic deformation is: the performance evolution is driven by a reconfigurable magnetoelectric coupling network.

[0056] The excellent dynamic and static properties of the magnetoelectric coupling gel prepared in this embodiment for electromagnetic wave absorption under dynamic deformation stem from its reconfigurable multidimensional magnetoelectric coupling network. During stretching, the polymer chains drive the slippage of the GO layer and the tilting of MWCNTs, while Fe3O4 and ACS particles undergo distribution and recombination to form a dynamically reconfigured conductive and magnetic array. This structural adaptive mechanism directly regulates impedance matching and electromagnetic parameters, ensuring that the material maintains macroscopic structural integrity and electromagnetic function continuity under dynamic conditions, providing a new design path for flexible electromagnetic control materials.

[0057] In this embodiment, by applying tensile strain to the prepared magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation, the complex permittivity and complex permeability of the material are synergistically controlled by utilizing the directional reconstruction of the pre-constructed "magnetic-electrical-dielectric" coupling network inside the material, thereby actively maintaining or optimizing its broadband electromagnetic wave absorption performance under deformation.

[0058] Example 2 The method for preparing the magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation in this embodiment is as follows: Preparation of S1 and Cu2O octahedral particles: 0.8 g CuCl2·2H2O and 15 g polyvinylpyrrolidone (PVP) were added to 400 mL of deionized water and stirred for 40 min to obtain a dark brown solution. Then, 40 mL of 2.0 mol / L NaOH aqueous solution was added dropwise. After stirring at 60 °C for 40 min, 40 mL of 0.6 mol / L ascorbic acid aqueous solution was added dropwise. After reacting at 60 °C for 4 h, the precipitate was filtered and washed with deionized water 4 times and anhydrous ethanol 4 times. After vacuum drying at 60 °C for 6 h, Cu2O octahedral particles were obtained. Preparation of S2 and Cu2O@CuS: 0.16 g of Cu2O octahedral particles obtained from S1 were dispersed in 200 mL of deionized water. After ultrasonic treatment for 20 min using a cell disruptor at 500 W, 100 mL of 2.5 mmol / L Na2S aqueous solution was added dropwise to induce a sulfidation reaction in the Cu2O template. After stirring for 40 min, the precipitate was collected by vacuum filtration. The precipitate was washed four times with deionized water and four times with anhydrous ethanol. After vacuum drying at 60 °C for 6 h, octahedral particles with a core-shell structure were obtained, denoted as Cu2O@CuS. S3. Preparation of hollow Cu2O@CuS particles: 0.09 g of Cu2O@CuS obtained from S2 was dispersed in 200 mL of 50% ethanol aqueous solution. After ultrasonic dispersion for 20 min at 500 W, 80 mL of 1.0 mol / L Na2S2O3 aqueous solution was added and stirred for 40 min. The precipitate was collected by vacuum filtration. The precipitate was washed four times with deionized water and four times with anhydrous ethanol. After vacuum drying at 60 °C for 6 h, hollow Cu2O@CuS particles were obtained, denoted as H-Cu2O@CuS. The thin Cu2O layer retained inside the CuS shell provided conditions for the uniform introduction of Ag particles. Preparation of S4 and Ag / CuO@CuS particles: H-Cu2O@CuS obtained from 0.03g of S3 was dispersed in 100mL of deionized water and ultrasonically treated for 20min at 500W. Then, 10mL of 0.3mol / L AgNO3 aqueous solution and 10mL of 0.1mol / L ascorbic acid aqueous solution were added. The mixture was stirred at room temperature for 40min, and the precipitate was collected by vacuum filtration. The precipitate was washed with deionized water 4 times and anhydrous ethanol 4 times. After vacuum drying at 60℃ for 6h, Ag / CuO@CuS particles with a particle size of 1.4μm were obtained, denoted as ACS. S5. Preparation of magnetoelectric coupling gel: 5g of monomeric acrylamide (AM), 2g of monomeric acrylic acid (AA), 30mg of crosslinking agent N,N'-methylenebisacrylamide (MBA), and 20mg of photoinitiator I2959 were mixed thoroughly and then dissolved in 10mL of 1-ethyl-3-methylimidazolium sulfate ([EMI]). + [ES] - In an ionic liquid, 0.01 g of graphene oxide (GO), 0.01 g of multi-walled carbon nanotubes (MWCNTs), 0.01 g of Fe3O4, and 0.02 g of Ag / CuO@CuS particles obtained from S4 were added. The mixture was stirred for 10 min in an ice bath at a speed of 800 r / min, followed by ultrasonic treatment for 10 min (6 s working cycle, 3 s interval, 1000 W power) to obtain a prepolymer solution. This solution was then transferred to a polytetrafluoroethylene (PTFE) mold with a depth of 1 mm. A glass plate was then placed over the PTFE mold to ensure a smooth surface. Free radical polymerization was initiated under a 365 nm UV lamp for 30 min to obtain a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation.

[0059] This material retains excellent electromagnetic wave absorption performance under deformation conditions, and the optimal absorption thickness can be adaptively adjusted with tensile strain: at a matching thickness of approximately 3.1 mm, the effective electromagnetic wave absorption region of the original composite gel can fully cover the X-band (8.4-12.2 GHz), with a minimum reflection loss of -20 dB. When the composite gel is stretched to 50% strain, the matching thickness of its effective absorption region adaptively shrinks to approximately 2 mm, corresponding to a minimum reflection loss of -12 dB, and the broadband absorption characteristics of the X-band do not decrease, confirming that the material has good effectiveness and structural stability in dynamic practical applications.

[0060] This embodiment also provides the application of the magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation prepared by the above preparation method, which is used to prepare electromagnetic protection products.

[0061] Example 3 The method for preparing the magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation in this embodiment is as follows: Preparation of S1 and Cu2O octahedral particles: 0.743 g CuCl2·2H2O and 14.16 g polyvinylpyrrolidone (PVP) were added to 400 mL of deionized water and stirred for 35 min to obtain a dark brown solution. Then, 40 mL of 2.0 mol / L NaOH aqueous solution was added dropwise. After stirring at 65 °C for 35 min, 40 mL of 0.6 mol / L ascorbic acid aqueous solution was added dropwise. After reacting at 65 °C for 3.5 h, the precipitate was filtered and washed three times with deionized water and three times with anhydrous ethanol. After vacuum drying at 60 °C for 5 h, Cu2O octahedral particles were obtained. Preparation of S2 and Cu2O@CuS: 0.1555 g of Cu2O octahedral particles obtained from S1 were dispersed in 200 mL of deionized water. After ultrasonic treatment for 15 min using a cell disruptor at 450 W, 100 mL of 2.5 mmol / L Na2S aqueous solution was added dropwise to induce a sulfidation reaction in the Cu2O template. After stirring for 35 min, the precipitate was collected by vacuum filtration. The precipitate was washed three times with deionized water and three times with anhydrous ethanol. After vacuum drying at 60 °C for 5 h, octahedral particles with a core-shell structure were obtained, denoted as Cu2O@CuS. S3. Preparation of hollow Cu2O@CuS particles: 0.0855 g of Cu2O@CuS obtained from S2 was dispersed in 200 mL of 50% ethanol aqueous solution. After ultrasonic dispersion for 15 min at 450 W, 80 mL of 1.0 mol / L Na2S2O3 aqueous solution was added and stirred for 35 min. The precipitate was collected by vacuum filtration. The precipitate was washed three times with deionized water and three times with anhydrous ethanol. After vacuum drying at 60 °C for 5 h, hollow Cu2O@CuS particles were obtained, denoted as H-Cu2O@CuS. The thin Cu2O layer retained inside the CuS shell provided conditions for the uniform introduction of Ag particles. Preparation of S4 and Ag / CuO@CuS particles: 0.025 g of H-Cu2O@CuS obtained from S3 was dispersed in 100 mL of deionized water and ultrasonically treated for 15 min at 450 W. Then, 10 mL of 0.3 mol / L AgNO3 aqueous solution and 10 mL of 0.1 mol / L ascorbic acid aqueous solution were added. The mixture was stirred at room temperature for 35 min, and the precipitate was collected by vacuum filtration. The precipitate was washed three times with deionized water and three times with anhydrous ethanol. After vacuum drying at 60 °C for 5 h, Ag / CuO@CuS particles with a particle size of 1.3 μm were obtained, denoted as ACS. S5. Preparation of magnetoelectric coupling gel: 4.5g of monomeric acrylamide (AM), 2g of monomeric acrylic acid (AA), 30mg of crosslinking agent N,N'-methylenebisacrylamide (MBA), and 20mg of photoinitiator I2959 were mixed thoroughly and then dissolved in 10mL of 1-ethyl-3-methylimidazolium sulfate ([EMI]). + [ES] - In an ionic liquid, 0.01 g of graphene oxide (GO), 0.01 g of multi-walled carbon nanotubes (MWCNTs), 0.01 g of Fe3O4, and 0.02 g of Ag / CuO@CuS particles obtained from S4 were added. The mixture was stirred for 8 min in an ice bath at a speed of 800 r / min, followed by ultrasonic treatment for 10 min (6 s working cycle, 3 s interval, 900 W power) to obtain a prepolymer solution. This solution was then transferred to a polytetrafluoroethylene (PTFE) mold with a depth of 1 mm. A glass plate was then placed over the PTFE mold to ensure a smooth surface. Free radical polymerization was initiated under a 365 nm UV lamp for 30 min to obtain a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation.

[0062] This composite gel material exhibits both the ability to maintain its microwave absorption performance under deformation and the adaptability of its optimal absorption thickness to the strain: in its original state, a thickness of 3 mm is sufficient to achieve effective absorption across the entire X-band (8.4-12.2 GHz), with a minimum reflection loss of -18 dB; under 50% tensile strain, the effective absorption matching thickness is adjusted to 2.2 mm, with a minimum reflection loss of -13 dB, while maintaining the same broadband absorption performance in the X-band, fully demonstrating its microwave absorption effectiveness and structural stability in dynamic service scenarios.

[0063] This embodiment also provides the application of the magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation prepared by the above preparation method, which is used to prepare electromagnetic protection products.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation, characterized in that, The method is as follows: Preparation of S1 and Cu2O octahedral particles: CuCl2·2H2O and polyvinylpyrrolidone were added to deionized water and stirred for 30-40 minutes. Then, NaOH aqueous solution was added dropwise. After stirring for 30-40 minutes at 55-65°C, ascorbic acid aqueous solution was added dropwise. The mixture was then reacted at 55-65°C for 3-4 hours. The resulting precipitate was filtered, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain Cu2O octahedral particles. Preparation of S2 and Cu2O@CuS: The Cu2O octahedral particles obtained in S1 were dispersed in deionized water, ultrasonically treated, and then Na2S aqueous solution was added dropwise. After stirring for 30 min to 40 min, the precipitate was collected by vacuum filtration. The precipitate was washed with deionized water and anhydrous ethanol in sequence, and then dried under vacuum to obtain octahedral particles with a core-shell structure, denoted as Cu2O@CuS. S3. Preparation of hollow Cu2O@CuS particles: The Cu2O@CuS obtained in S2 was dispersed in an ethanol aqueous solution. After ultrasonic dispersion, Na2S2O3 aqueous solution was added and stirred for 30 min to 40 min. The precipitate was collected by vacuum filtration. The precipitate was washed with deionized water and anhydrous ethanol in sequence and dried under vacuum to obtain hollow Cu2O@CuS particles, denoted as H-Cu2O@CuS. Preparation of S4 and Ag / CuO@CuS particles: The H-Cu2O@CuS obtained in S3 was dispersed in deionized water, ultrasonically treated, and then AgNO3 aqueous solution and ascorbic acid aqueous solution were added. The mixture was stirred at room temperature for 30 min to 40 min, and the precipitate was collected by vacuum filtration. The precipitate was washed with deionized water and anhydrous ethanol in sequence, and then dried under vacuum to obtain Ag / CuO@CuS particles, denoted as ACS. S5. Preparation of magnetoelectric coupling gel: After uniformly mixing acrylamide monomer, acrylic acid monomer, crosslinking agent N,N'-methylenebisacrylamide, and photoinitiator I2959, the mixture was dissolved in 1-ethyl-3-methylimidazolium sulfate ionic liquid. Then, Ag / CuO@CuS particles obtained from graphene oxide, multi-walled carbon nanotubes, Fe3O4, and S4 were added. After stirring in an ice bath, the mixture was ultrasonically treated to obtain a prepolymer solution, which was transferred to a polytetrafluoroethylene mold. A glass plate was then placed on the polytetrafluoroethylene mold, and free radical polymerization was initiated under a 365 nm ultraviolet lamp for 30 min to obtain a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation.

2. The method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation according to claim 1, characterized in that, The ratio of CuCl2·2H2O, polyvinylpyrrolidone, deionized water, NaOH aqueous solution, and ascorbic acid aqueous solution in S1 is (0.686~0.8) g : (13.32~15) g : 400 mL : 40 mL : 40 mL; the concentration of the NaOH aqueous solution is 2.0 mol / L; and the concentration of the ascorbic acid aqueous solution is 0.6 mol / L.

3. The method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation according to claim 1, characterized in that, The number of times deionized water washing is performed in S1 to S4 is 3 to 4 times, and the number of times anhydrous ethanol washing is performed is 3 to 4 times; the vacuum drying conditions in S1 to S4 are 60℃, 4h to 6h.

4. The method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation according to claim 1, characterized in that, The ultrasound conditions in S2 to S4 are 400-500W for 10-20 minutes.

5. The method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation according to claim 1, characterized in that, The ratio of Cu2O octahedral particles, deionized water, and Na2S aqueous solution in S2 is (0.151~0.16) g: 200 mL: 100 mL; the concentration of the Na2S aqueous solution is 2.5 mmol / L.

6. The method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation according to claim 1, characterized in that, The ratio of Cu2O@CuS, ethanol aqueous solution, and Na2S2O3 aqueous solution in S3 is (0.081~0.09) g: 200 mL: 80 mL; the volume fraction of the ethanol aqueous solution is 50%; and the concentration of the Na2S2O3 aqueous solution is 1.0 mol / L.

7. The method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation according to claim 1, characterized in that, The ratio of H-Cu2O@CuS, deionized water, AgNO3 aqueous solution and ascorbic acid aqueous solution in S4 is (0.02~0.03) g: 100 mL: 10 mL: 10 mL; the concentration of AgNO3 aqueous solution is 0.3 mol / L and the concentration of ascorbic acid aqueous solution is 0.1 mol / L.

8. The method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation according to claim 1, characterized in that, The ratio of the monomer acrylamide, monomer acrylic acid, crosslinking agent N,N'-methylenebisacrylamide, photoinitiator I2959, 1-ethyl-3-methylimidazolium sulfate ethyl ionic liquid, graphene oxide, multi-walled carbon nanotubes, Fe3O4 and Ag / CuO@CuS particles in S5 is (4~5) g: 2 g: 30 mg: 20 mg: 10 mL: 0.01 g: 0.01 g: 0.02 g.

9. The method for preparing a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation according to claim 1, characterized in that, The stirring conditions in S5 are: rotation speed 800 r / min, 5 min to 10 min; the ultrasonic treatment conditions in S5 are: working time 10 min; working cycle 6 s, interval 3 s, power 800 W to 1000 W.

10. An application of a magnetoelectric coupling gel for electromagnetic wave absorption under dynamic deformation, prepared by the preparation method according to any one of claims 1-9, characterized in that, The magnetoelectric coupling gel used for electromagnetic wave absorption under dynamic deformation is used to prepare electromagnetic protection products.

Images