Asymmetric layered structural design with metal microtube conductive network for absorption-dominated electromagnetic interference shielding

Abstract

Conductive polymer composites (CPCs) with high conductivity components designed based on impedance mismatch strategy have high electromagnetic interference shielding effectiveness (EMI SE) yet cause serious secondary pollution due to their strong reflection. A well-designed double-layer fiber-based waterborne polyurethane (WPU) composite with electro-magnetic asymmetric distribution for EMI shielding with absorption-dominant is realized. When the electromagnetic waves (EMWs) enter the AF@Ni/Cu/Fe3O4/WPU composite through gaps of the nonwoven fabric, incoming microwaves will undergo a special ‘absorption-reflection-reabsorption’ process between the metal microtubules, and the electromagnetic shielding effectiveness (EMI SE) of the composite reaches 55.8 dB in X-band, which indicates approximately 99.9997% of EWMs are attenuated in the propagation process. Herein, absorption (SEA, 50.1 dB) contributes 89.8% to the total SE and the lowest power coefficient of reflection (R) reaches 0.62. This work expands the application field of high-performance aramid fibers, and provides a reliable strategy to reduce secondary electromagnetic radiation pollution.