Asymmetric Bilayer PA6@Co/AgNWs/PVDF Composite Enabling Absorption-Dominant High-Efficiency Electromagnetic Interference Shielding

Advances in electronic device miniaturization and system integration, alongside rapid progress in wireless communication technologies, have significantly amplified electromagnetic interference problems. This development necessitates the creation of high-performance electromagnetic shielding materials. This study presents a new design for electromagnetic shielding composites comprising an asymmetric structure of cobalt-coated nylon 6 microspheres (PA6@Co), silver nanowires (AgNWs) and poly(vinylidene fluoride) (PVDF). Specifically, PA6 microspheres were prepared using anionic reaction-induced phase separation, and cobalt was plated on their surfaces, thereby forming magnetic PA6@Co microspheres. The magnetic saturation intensity of these microspheres can reach 80 emu/g. The asymmetric PA6@Co/AgNWs/PVDF electromagnetic shielding composites with absorption-dominant characteristics were constructed using AgNWs as the conductive filler and PVDF as the matrix. The results show that within the X-band (8.2–12.4 GHz) range, the PA6@Co/AgNWs/PVDF composite material exhibits excellent electromagnetic shielding performance. Its maximum electromagnetic shielding efficiency (SET) reaches 48.1 dB, and the absorption coefficient (A) is 0.8, demonstrating a distinct absorption-dominant shielding characteristic. This asymmetric structural design strategy solves the limitations of traditional shielding materials and provides a new approach to developing environmentally friendly, efficient electromagnetic shielding materials.