Interfacial Regulation and Modeling of Electromagnetic Shielding in Liquid Gallium-Modified Copper Fabric/Polyurea Composites

Abstract

Flexible electromagnetic interference (EMI) shielding materials with controllable electromagnetic responses are highly desired for high-frequency and deformable electronics. Here, a flexible sandwich-structured composite membrane (PU-Ga@CuF) is fabricated via liquid-gallium-enabled interfacial regulation of copper-coated fabric combined with polyurea encapsulation. Dense Cu-Ga interfacial coupling suppresses interfacial voids and reconstructs electromagnetic loss pathways, inducing a transition from absorption-dominated shielding in pristine CuF to a reflection-regulated response with improved frequency stability, while maintaining mechanical flexibility. To quantitatively interpret this mechanism transition, frequency-dependent electromagnetic parameters are analyzed, and a physically motivated magnetic-loss fitting model incorporating layer-resolved attenuation and interfacial transmission effects is established. The model shows good agreement with experimental results and provides a quantitative framework for understanding electromagnetic dissipation in multilayer flexible composites. This work offers an engineering-scalable interfacial strategy for the rational design of flexible EMI shielding materials.