A material applicable to electromagnetic field space control and its application

Abstract

The application provides a material applicable to electromagnetic field space control and application thereof, and relates to the technical field of materials.The material is prepared from the following raw materials: 100 parts of poly(4-vinylpyridine)-b-polydimethylsiloxane, 30-60 parts of ionic liquid, 20-50 parts of Fe3O4 nanoparticles, 10-30 parts of MXene, 400-600 parts of mixed solvent, 1-5 parts of photoinitiator and 15-40 parts of polyethylene glycol diacrylate.The material takes poly(4-vinylpyridine)-b-polydimethylsiloxane block copolymer as a matrix, combines ionic liquid, Fe3O4 nanoparticles with surface modification of oleic acid and MXene, and constructs a composite system with excellent flexibility and structural stability, thereby supporting the further development of electromagnetic field space control technology.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a material applicable to spatial control of electromagnetic fields and its applications. Background Technology

[0002] With the rapid development of flexible electronics, smart communication devices, and integrated electromagnetic systems, the effective control of electromagnetic fields has become a core focus in the design and application of high-performance materials. In fields such as wearable electronics, smart sensing, high-precision imaging, stealth technology, and novel metamaterials, higher demands are being placed on materials with tunable electromagnetic response characteristics. These materials need to possess comprehensive properties such as lightweight, flexibility, controllable structure, and tunable electromagnetic parameters to meet the dynamic adjustment requirements of electromagnetic wave absorption, reflection, or transmission behavior in complex application scenarios.

[0003] Currently, research on electromagnetically modulated functional materials largely focuses on introducing conductive, magnetic, and other functional fillers into polymer matrices, aiming to achieve the electromagnetic response characteristics of composite materials by controlling the type, content, and distribution of the fillers. However, existing composite systems generally suffer from poor compatibility and uneven dispersion between the functional components and the matrix, which can easily lead to phase separation, interface defects, and carrier localization, thereby weakening the overall electromagnetic response efficiency and stability. Furthermore, achieving uniform dispersion of nanoscale functional units in the matrix while maintaining good material flexibility, and forming a controllable conductive or magnetic response network under external fields, remains a key bottleneck in current technological development.

[0004] Furthermore, existing fabrication processes largely rely on empirical control, limiting their ability to precisely construct the microstructure of materials. This makes it difficult to achieve precise design of electromagnetic properties and programmable control of spatial distribution, thus restricting their practical application in high-end fields such as intelligent electromagnetic shielding, tunable metamaterials, high-sensitivity electromagnetic sensing, and next-generation imaging devices.

[0005] Therefore, there is an urgent need to develop a new material system that combines excellent flexibility, highly dispersed functional units, adjustable structure, and designable electromagnetic response performance to support the further development of electromagnetic field spatial control technology.

[0006] Therefore, this invention is proposed. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a material applicable to electromagnetic field spatial control and its application. This material is a novel material system possessing excellent flexibility, highly dispersed functional units, adjustable structure, and designable electromagnetic response performance, thereby supporting the further development of electromagnetic field spatial control technology.

[0008] In order to achieve the objective of this invention, the following technical solution is adopted: This invention provides a material applicable to electromagnetic field spatial control, which is prepared from the following raw materials by mass parts: 100 parts of poly(4-vinylpyridine)-b-polydimethylsiloxane, 30-60 parts of ionic liquid, 20-50 parts of Fe3O4 nanoparticles, 10-30 parts of MXene, 400-600 parts of mixed solvent, 1-5 parts of photoinitiator, and 15-40 parts of polyethylene glycol diacrylate.

[0009] Furthermore, the mixture contains 100 parts of poly(4-vinylpyridine)-b-polydimethylsiloxane, 45 parts of ionic liquid, 35 parts of Fe3O4 nanoparticles, 20 parts of MXene, 500 parts of mixed solvent, 3 parts of photoinitiator, and 25 parts of polyethylene glycol diacrylate.

[0010] The molecular formula of poly(4-vinylpyridine)-b-polydimethylsiloxane is: .

[0011] Furthermore, the Fe3O4 nanoparticles are modified with oleic acid.

[0012] Furthermore, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt or 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0013] Furthermore, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0014] Furthermore, the photoinitiator is any one of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, or 2,2-dimethoxy-2-phenylacetophenone.

[0015] Furthermore, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0016] Furthermore, the MXene is Ti3C2T. x .

[0017] Furthermore, the mixed solvent is a mixture of chloroform, dichloromethane, and cyclohexane, and the volume ratio of the mixture of chloroform, dichloromethane, and cyclohexane is 3:1:1.

[0018] This invention also provides a method for preparing the above-mentioned material applicable to electromagnetic field spatial control, comprising the following steps: S1. Modify Fe3O4 nanoparticles to obtain Fe3O4 nanoparticle dispersion; S2. Disperse poly(4-vinylpyridine)-b-polydimethylsiloxane in a mixed solvent, add an ionic liquid, stir to dissolve, and obtain a mixed solution; S3. Add polyethylene glycol diacrylate, Fe3O4 nano-dispersion, and MXene sequentially to the mixture, disperse by ultrasonication, and stir until homogeneous; S4. Add photoinitiator to the product of S3, stir evenly in the dark, and degas under vacuum to obtain coating liquid; S5. Apply the coating liquid to the mold, place it in a magnetic field and let it stand. While maintaining the magnetic field, irradiate it with ultraviolet light under an inert atmosphere and dry it to obtain a material for electromagnetic field space control.

[0019] Furthermore, S1 specifically includes: Fe3O4 nanoparticles were dispersed in ethanol, oleic acid was added, and the mixture was refluxed and stirred at 60℃-80℃ for 2h-4h. After centrifugation and washing, the mixture was redispersed in a mixed solvent to obtain an oleic acid-modified Fe3O4 nanoparticle dispersion.

[0020] Furthermore, in step S5, the sample is placed in a magnetic field of 0.1T-0.5T and left to stand for 5-60 minutes.

[0021] The present invention also provides the application of the above-mentioned materials applicable to electromagnetic field spatial control in the fabrication of photodetectors, gas sensors, artificial synaptic devices or flexible logic circuits.

[0022] The present invention has the following technical effects: This invention utilizes a poly(4-vinylpyridine)-b-polydimethylsiloxane block copolymer as the matrix, combined with an ionic liquid, oleic acid-modified Fe3O4 nanoparticles, and MXene to construct a composite system exhibiting both excellent flexibility and structural stability. The block copolymer effectively improves the interfacial compatibility between the inorganic functional components and the organic matrix, suppressing phase separation and charge trapping. The oleic acid-modified Fe3O4 nanoparticles can achieve directional alignment under a magnetic field, synergistically forming an ordered conductive / magnetic response network with the highly conductive MXene, significantly enhancing the tunability of the material's electromagnetic parameters.

[0023] In terms of preparation method, this invention combines low-temperature stirring with ultrasonic dispersion to ensure uniform dispersion of functional fillers in the matrix; further, by combining controllable uniform magnetic field induction and curing processes, precise control and spatial programming of the material's internal microstructure are achieved. The resulting material, while maintaining good flexibility, exhibits excellent electromagnetic shielding effectiveness, tunable electromagnetic response characteristics, and environmental stability. It can be widely used in fields such as intelligent electromagnetic shielding, tunable metamaterials, electromagnetic sensors, imaging devices, and stealth coatings, providing reliable material support for spatial control of electromagnetic fields. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] In a first aspect, the present invention provides a material applicable to electromagnetic field spatial control, which is prepared from the following raw materials by mass parts: 100 parts of poly(4-vinylpyridine)-b-polydimethylsiloxane, 30-60 parts of ionic liquid, 20-50 parts of Fe3O4 nanoparticles, 10-30 parts of MXene, 400-600 parts of mixed solvent, 1-5 parts of photoinitiator, and 15-40 parts of polyethylene glycol diacrylate.

[0026] In some embodiments, 100 parts of poly(4-vinylpyridine)-b-polydimethylsiloxane, 45 parts of ionic liquid, 35 parts of Fe3O4 nanoparticles, 20 parts of MXene, 500 parts of mixed solvent, 3 parts of photoinitiator, and 25 parts of polyethylene glycol diacrylate are used.

[0027] The molecular formula of poly(4-vinylpyridine)-b-polydimethylsiloxane is: .

[0028] Poly(4-vinylpyridine)-b-polydimethylsiloxane (P4VP-b-PDMS) provides a flexible framework, while the pyridine groups can interact with ionic liquids and inorganic fillers to improve interfacial compatibility. Ionic liquids enhance ionic conductivity, improve dielectric response, and assist in filler dispersion. Fe3O4 nanoparticles provide magnetic responsiveness and can align themselves in a magnetic field. MXene, a highly conductive two-dimensional material, constructs a conductive network. Polyethylene glycol diacrylate forms a three-dimensional network under ultraviolet light, fixing the structure. The above formulation yields a flexible composite material with tunable electromagnetic parameters and stable structure. Furthermore, the functional components work synergistically to improve electromagnetic shielding, dielectric response, and magnetic response performance.

[0029] In some embodiments, the Fe3O4 nanoparticles are modified with oleic acid.

[0030] Oleic acid, as a surfactant, coats the surface of Fe3O4 nanoparticles, improving their dispersibility in organic solvents and polymer matrices, preventing agglomeration, thereby enhancing the interfacial compatibility between Fe3O4 and the polymer matrix, improving the uniformity of magnetic response unit distribution, and ultimately improving the overall electromagnetic performance stability of the material.

[0031] In some embodiments, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt or 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0032] In some embodiments, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0033] The aforementioned ionic conductivity can improve the dielectric constant and ionic conductivity of materials, and enhance their sensitivity to electromagnetic field response.

[0034] In some embodiments, the photoinitiator is any one of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, or 2,2-dimethoxy-2-phenylacetophenone.

[0035] In some embodiments, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0036] The aforementioned high-efficiency ultraviolet photoinitiator can generate free radicals under ultraviolet irradiation, initiating the cross-linking polymerization of polyethylene glycol diacrylate (PEGDA), achieving a rapid and controllable photocuring process, and ensuring that the material is rapidly cross-linked and fixed after the magnetic field induces structural shaping.

[0037] In some embodiments, the MXene is Ti3C2T x .

[0038] The material contains hydroxyl, oxygen, or fluorine functional groups on its surface, which readily interact with the polymer matrix to provide a highly conductive network, enhancing electromagnetic shielding and dielectric properties. Simultaneously, it synergizes with Fe3O4 to form a conductive-magnetic dual-response structure.

[0039] In some embodiments, the mixed solvent is a mixture of chloroform, dichloromethane, and cyclohexane, wherein the volume ratio of the mixture of chloroform, dichloromethane, and cyclohexane is 3:1:1.

[0040] Chloroform and dichloromethane are good organic solvents that can dissolve P4VP-b-PDMS and PEGDA; cyclohexane adjusts polarity and volatility, optimizing the film-forming process. It also improves the solubility and dispersion uniformity of each component. Furthermore, it allows control of the coating solution's viscosity and drying rate, which is beneficial for film quality.

[0041] Secondly, the present invention also provides a method for preparing the above-mentioned material applicable to electromagnetic field spatial control, comprising the following steps: S1. Modify Fe3O4 nanoparticles to obtain Fe3O4 nanoparticle dispersion; S2. Disperse poly(4-vinylpyridine)-b-polydimethylsiloxane in a mixed solvent, add an ionic liquid, stir to dissolve, and obtain a mixed solution; S3. Add polyethylene glycol diacrylate, Fe3O4 nano-dispersion, and MXene sequentially to the mixture, disperse by ultrasonication, and stir until homogeneous; S4. Add photoinitiator to the product of S3, stir evenly in the dark, and degas under vacuum to obtain coating liquid; S5. Apply the coating liquid to the mold, place it in a magnetic field and let it stand. While maintaining the magnetic field, irradiate it with ultraviolet light under an inert atmosphere and dry it to obtain a material for electromagnetic field space control.

[0042] In some embodiments, S1 specifically includes: Fe3O4 nanoparticles were dispersed in ethanol, oleic acid was added, and the mixture was refluxed and stirred at 60℃-80℃ for 2h-4h. After centrifugation and washing, the mixture was redispersed in a mixed solvent to obtain an oleic acid-modified Fe3O4 nanoparticle dispersion.

[0043] In some embodiments, in step S5, the object is placed in a magnetic field of 0.1T-0.5T and left to stand for 5-60 minutes.

[0044] The present invention also provides the application of the above-mentioned materials applicable to electromagnetic field spatial control in the fabrication of photodetectors, gas sensors, artificial synaptic devices or flexible logic circuits.

[0045] The following is a detailed explanation using specific embodiments: Example 1 Weigh: 100g of poly(4-vinylpyridine)-b-polydimethylsiloxane, 45g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 35g of Fe3O4 nanoparticles, 20g of MXene, 500g of mixed solvent (a mixture of chloroform, dichloromethane, and cyclohexane in a volume ratio of 3:1:1), 3g of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 25 parts of polyethylene glycol diacrylate.

[0046] Oleic acid-modified Fe3O4: Fe3O4 nanoparticles were added to ethanol and ultrasonically dispersed evenly. Oleic acid was added at 5%-20% (15% in this example) of the mass of Fe3O4 nanoparticles, and the mixture was refluxed and stirred at 60-80 °C for 2-4 hours. Then, the mixture was centrifuged and washed with ethanol 3-5 times to remove unadsorbed oleic acid. The washed product was redispersed in a mixed solvent to obtain an oleic acid-modified Fe3O4 nanoparticle dispersion.

[0047] Poly(4-vinylpyridine)-b-polydimethylsiloxane was dispersed in a mixed solvent, and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was added and stirred to dissolve, thus obtaining a mixed solution.

[0048] MXene Fe3O4 nano-dispersion was added to the mixture, ultrasonically dispersed, and stirred until homogeneous. Then, 2-hydroxy-2-methyl-1-phenyl-1-propanone was added and stirred until homogeneous in the dark. Vacuum degassing was performed to obtain a coating solution. The coating solution was coated onto a mold, placed in a magnetic field, and kept still while being irradiated with ultraviolet light under an inert atmosphere. The mold was then dried to obtain a material for electromagnetic field space control.

[0049] Experiment Example 1: Electromagnetic Performance Test 1.1 Electromagnetic shielding effectiveness Using a vector network analyzer, the thin film sample to be tested was cut into a standard size of 22.9 mm × 10.2 mm and placed in a waveguide sample holder. The test frequency range was 2-18 GHz. The total shielding effectiveness was calculated by testing the scattering parameters.

[0050] 1.2 Dielectric constant and dielectric loss An impedance analyzer was used to sputter gold electrodes onto both sides of the thin film sample. The test frequency range was 100Hz-1MHz. An AC voltage of 1 V was applied, and the changes in dielectric constant (ε') and dielectric loss (tan δ) with frequency were recorded.

[0051] 1.3 Magnetic property testing Using a vibrating sample magnetometer (VSM), the thin film sample was cut into 5mm×5mm pieces, and the room temperature hysteresis loops parallel to and perpendicular to the magnetic field direction were measured respectively. The magnetic field scanning range was -10kOe to 10kOe, and the saturation magnetization (Ms) and coercivity (Hc) were recorded.

[0052] 1.4 Conductivity Test A four-probe tester was used to place the thin film sample on the test stage, with the four probes making good contact with the sample surface. A constant current was applied, the voltage drop was measured, and the surface conductivity (σ) was calculated.

[0053] The experimental results are shown in Table 1.

[0054] Table 1: Electromagnetic performance test results Experiment Example 2: Mechanical Property Testing The film from Example 1 was cut into dumbbell-shaped standard strips (total length 35 mm, gauge length 10 mm, width 4 mm), and tensile tests were performed using a universal tensile testing machine at a tensile rate of 10 mm / min and an initial clamping distance of 20 mm. Five parallel samples were tested for each group of samples, and the average value was taken. The tensile strength (MPa) and elongation at break (%) were recorded. The experimental results are shown in Table 2.

[0055] Table 2: Mechanical Performance Test Results Experiment Example 3: Thermal Stability Test Thermal stability tests were performed using a thermogravimetric analyzer (TGA). 5-10 mg of sample was weighed and placed in an alumina crucible. Under a nitrogen atmosphere (flow rate 50 mL / min), the temperature was increased from 30℃ to 800℃ at a heating rate of 10℃ / min. The mass change curve of the sample with temperature was recorded, and the thermal decomposition temperature (Td, the temperature corresponding to a 5% mass loss) and the char residue at 800℃ were read.

[0056] Table 3: Thermal stability test results Experiment Example 4: Application Performance Verification The thin film sample was fixed on a flexible bending tester, with a bending radius of 5 mm and a bending angle of 180°. It was subjected to 1000 cyclic bending cycles at a frequency of 30 cycles / min. After every 200 bends, the EMISE (X-band) of the sample was tested using a vector network analyzer, and the performance retention rate was calculated (retention rate = EMISE after bending / initial EMISE × 100%). The experimental results are shown in Table 4.

[0057] Table 4: Application Performance Verification Results 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; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A material applicable to spatial control of electromagnetic fields, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts of poly(4-vinylpyridine)-b-polydimethylsiloxane, 30-60 parts of ionic liquid, 20-50 parts of Fe3O4 nanoparticles, 10-30 parts of MXene, 400-600 parts of mixed solvent, 1-5 parts of photoinitiator, and 15-40 parts of polyethylene glycol diacrylate.

2. The material applicable to electromagnetic field spatial control according to claim 1, characterized in that, The Fe3O4 nanoparticles were modified with oleic acid.

3. The material applicable to electromagnetic field spatial control according to claim 1, characterized in that, The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt or 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

4. The material applicable to electromagnetic field spatial control according to claim 1, characterized in that, The photoinitiator is any one of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, or 2,2-dimethoxy-2-phenylacetophenone.

5. The material applicable to electromagnetic field spatial control according to claim 1, characterized in that, The MXene is Ti3C2T x .

6. The material applicable to electromagnetic field spatial control according to claim 1, characterized in that, The mixed solvent is a mixture of chloroform, dichloromethane, and cyclohexane, and the volume ratio of the mixture of chloroform, dichloromethane, and cyclohexane is 3:1:

1.

7. A method for preparing a material applicable to electromagnetic field spatial control as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Modify Fe3O4 nanoparticles to obtain Fe3O4 nanoparticle dispersion; S2. Disperse poly(4-vinylpyridine)-b-polydimethylsiloxane in a mixed solvent, add an ionic liquid, stir to dissolve, and obtain a mixed solution; S3. Add polyethylene glycol diacrylate, Fe3O4 nano-dispersion, and MXene sequentially to the mixture, disperse by ultrasonication, and stir until homogeneous; S4. Add photoinitiator to the product of S3, stir evenly in the dark, and degas under vacuum to obtain coating liquid; S5. Apply the coating liquid to the mold, place it in a magnetic field and let it stand. While maintaining the magnetic field, irradiate it with ultraviolet light under an inert atmosphere and dry it to obtain a material for electromagnetic field space control.

8. The method for preparing a material applicable to electromagnetic field spatial control according to claim 7, characterized in that, S1 specifically includes: Fe3O4 nanoparticles were dispersed in ethanol, oleic acid was added, and the mixture was refluxed and stirred at 60℃-80℃ for 2h-4h. After centrifugation and washing, the mixture was redispersed in a mixed solvent to obtain an oleic acid-modified Fe3O4 nanoparticle dispersion.

9. The method for preparing a material applicable to electromagnetic field spatial control according to claim 7, characterized in that, In step S5, the sample is placed in a magnetic field of 0.1T-0.5T and left to stand for 5-60 minutes.

10. The application of a material applicable to electromagnetic field spatial control as described in any one of claims 1-6 in the fabrication of photodetectors, gas sensors, artificial synaptic devices, or flexible logic circuits.

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