Lightweight Three‐Layer EVA / LDPE Foams With Gradient‐Distributed CNT for Efficient EMI Shielding and Piezoresistive Sensing

ABSTRACT The swift progress in flexible wearable electronics has led to an immediate need for flexible conductive polymer composites (CPCs) featuring efficient and eco‐friendly electromagnetic interference (EMI) shielding as well as high‐sensitivity piezoresistive sensing in intelligent electronic systems. In this work, a facile two‐step strategy was proposed to fabricate three‐layer ethylene‐vinyl acetate copolymer (EVA) / carbon nanotube (CNT) / low density polyethylene (LDPE) composite foams with a gradient structure via hot‐press molding and supercritical carbon dioxide foaming. The as‐fabricated gradient‐structured EVA/CNT/LDPE composite foam exhibits excellent mechanical properties, green and high‐efficiency EMI shielding, and outstanding piezoresistive sensing characteristics. A maximum absolute specific EMI shielding effectiveness of 93 dB cm 2 /g with dominant absorption was achieved for EMI shielding. Meanwhile, the gradient three‐layer EVA/CNT/LDPE composite foams exhibited controllable force‐electrical response behaviors in a wide strain range, with a maximum gauge factor of 3.3, enabling high‐fidelity detection of various human motions. This study offers a feasible and scalable approach for the fabrication of exceptional performance gradient CPCs, laying a solid experimental basis for their applications in next‐generation intelligent flexible electronics.