Broadband electromagnetic wave absorbers are of great significance in military and civil fields. Absorbent coatings, although highly conformal, suffer from a narrow absorption band and a single absorption mechanism. In this work, inspired by the idea of bionics, we extracted the structural model of the moth-eye and designed the structure size by using electromagnetic simulation. Conductive graphite powder was selected as the wave absorbing agent due to its good dielectric and conductivity losses, and the final products were prepared according to the structural parameters obtained from the simulation. The result shows that the frequency bandwidth with absorption rate above 90% (reflection loss < -10 dB) of the products could reach 13 GHz, including C, X and Ku bands. The equivalent electromagnetic parameters of the bionic structure absorber were extracted by the inversion method, and its impedance gradient absorption mechanism was revealed by combining with the transmission line theory. In order to optimize low frequency (S-band) absorption, the introduction of Salisbury screen and bionic structure absorber combinations to form a composite absorber, the low-frequency absorption performance is effectively improved. The work shows that the combination of two absorption mechanisms, impedance gradient and interference, could effectively improve the absorption bandwidth of electromagnetic waves, providing a good idea for the design of the carbon based broadband absorber.

10.2139/ssrn.4199138

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Citations (1)

"Three-in-One" Multi-Scale Structural Design of Carbon Fiber-Based Composites for Personal Electromagnetic Protection and Thermal Management

Nano-Micro Letters (2023)

Ming Zhou Shujuan Tan Jingwen Wang Yue Wu Liang Leilei

Wearable devices with efficient thermal management and electromagnetic interference (EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers (CF) @ polyaniline (PANI) / silver nanowires (Ag NWs) composites with a "branch-trunk" interlocked micro/nanostructure were achieved through "three-in-one" multi-scale design. The reasonable assembly of the three kinds of one-dimensional (1D) materials can fully exert their excellent properties i.e., the superior flexibility of CF, the robustness of PANI, and the splendid conductivity of AgNWs. Consequently, the constructed flexible composite demonstrates enhanced mechanical properties with a tensile stress of 1.2 MPa, which was almost 6 times that of the original material. This is mainly attributed to the fact that the PNAI (branch) was firmly attached to the CF (trunk) through polydopamine (PDA), forming a robust interlocked structure. Meanwhile, the composite possesses excellent thermal insulation and heat preservation capacity owing to the synergistically low thermal conductivity and emissivity. More importantly, the conductive path of the composite established by the three 1D materials greatly improved its EMI shielding property and Joule heating performance at low applied voltage. This work paves the way for rational utilization of the intrinsic properties of 1D materials, as well as provides a promising strategy for designing wearable electromagnetic protection and thermal energy management devices.

Carbon fiber composite

10.1007/s40820-023-01144-z

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Citations (124)

Fabrication of Impact-Resistant and Wear-Recoverable Superhydrophobic Surfaces

ACS Omega (2019)

Chao‐Hua Xue Huidi Wang Zhanyou Ji Xiao-Jing Guo Bing‐Ying Liu

Robustness of superhydrophobic materials has been gradually taken into consideration for practical applications; however, little attention has been paid to the impact resistance of the superhydrophobicity of the materials. The present study demonstrated a new route for improving the mechanical durability, especially the impact resistance, of the superhydrophobic materials. First, poly(styrene-co-butadiene)/poly(ethylene-vinyl acetate) (SBR/EVA) composite monoliths with microscale cellular structures were manufactured by vulcanization-foaming processes. Then the composite monoliths were treated with sandpaper to create nanostructures above the revealed micropores after removing the uppermost skin, forming micro/nanotextured surfaces and giving improvements in superhydrophobicity. Due to the elastomeric nature of SBR and EVA, the superhydrophobicity of the monoliths can be maintained even while the material is mechanically impacted or compressed, and wearing helps improvement or recovery of the superhydrophobicity because of the self-similarity of the cellular structure inside the monoliths. Additionally, the obtained superhydrophobic materials are resistant to acidic, alkali, and salt liquors as well as organic solvents and have easy healing capacity of superhydrophobicity with a simple sanding treatment when destroyed by exposure to oxygen plasma.

Sandpaper

Microscale chemistry

Ethylene-vinyl acetate

10.1021/acsomega.9b02535

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Metal organic frameworks-derived iron carbide/ferroferric oxide/carbon/reduced graphene oxide nanocomposite with excellent electromagnetic wave absorption properties

Composites Communications (2020)

Weijie Li Ruiwen Shu Yue Wu Jiabin Zhang

Reflection loss

10.1016/j.coco.2020.100576

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Citations (37)