A Flexible, Mechanically Strong, and Anti‐Corrosion Electromagnetic Wave Absorption Composite Film with Periodic Electroconductive Patterns

Abstract

Demand for high-efficiency electromagnetic wave (EMW) absorption composite films continues to increase with technical advances in 5G telecommunications, wearable electronics, portable devices, and deployable military applications. However, realizing flexible ultra-thin single-layer EMW absorption composite films with multifunctionality, rather than using traditional particle absorbents, is a known challenge. In this study, the authors propose a series of polyimide (PI) reinforced composite films with periodic copperbased electroconductive units that possess tunable electrical properties for specific applications. These periodic units optimize the electric field distribution of the films in an alternating electromagnetic field, resulting in stronger power loss. Furthermore, the hierarchical structure and abundant heterogeneous interfaces of each unit contribute to multiple scattering and polarization loss. The obtained copper mesh@Cu 2−x S@PI (CCP) film shows excellent EM shielding performance (63.7 dB), while the Air@Cu 2−x S@PI (ACP) film delivers a superior specific absorbency value of 391.43% mm -1 in the X-band. Furthermore, owing to their mechanical properties, thermal conduction/dissipation performance, and excellent environmental stability characteristics, these films offer significant potential as high-performance EMW response materials with resistance to harsh conditions.

Anion‐Doping‐Induced Vacancy Engineering of Cobalt Sulfoselenide for Boosting Electromagnetic Wave Absorption

“…[6][7][8] Typically, dielectric loss contains polarization and conduction loss, which are related to electron formation, transport, and aggregation. [9,10] Anion vacancy engineering has been proven to be one of the studied and effective methods to this end. As for the conduction loss, previous reports have well revealed that these anionic vacancies can shape the band structure by introducing intra-band gap states, and benefits to the improved electronic conductivity.…”

Morphology control of eco-friendly chitosan-derived carbon aerogels for efficient microwave absorption at thin thickness and thermal stealth

“…In fact, a qualified absorber can only survive with multifunctionality in a complex environment. 5,9,10 For instance, the Ti 3 C 2 T x /carbon nano tube/ Co composite was prepared by Xiang et al 11 with a strong the minimum reflection loss (RL min ) of −85.8 dB and the flexibility, waterproof and photothermal conversion properties, which was expected to be a new generation of EMA materials. Huang et al prepared a graphene-based aerogel with excellent heat insulation and frost prevention, which provided a reference for the production of EMA materials used in complex environments.…”

Exploration of Twin‐Modified Grain Boundary Engineering in Metallic Copper Predominated Electromagnetic Wave Absorber

“…In this case, the EMA of these samples is mainly caused by dielectric loss. The complex permittivity (ε′ and ε″), which is closely related to the dielectric loss, [55][56][57] is further investigated (Figures S23 and S24, Supporting Information). Obviously, with the increase of Cu 2+1 O phase and the decrease of amorphous carbon, the average value of complex permittivity shows a regular downward trend (ε′: 7.72.42, ε″: 6.87-0.54), [58] especially in the CuNC20 sample (Figure 4h).…”