Stretchable polymer composite film based on pseudo-high carbon-filler loadings for electromagnetic interference shielding

Polymer composites with carbon-based filler (C-filler) are regarded as promising alternatives for flexible and stretchable electromagnetic interference (EMI) shielding materials. However, the poor mechanical properties caused by high-loadings largely hinders their practical applications, especially for the film. Herein, a class of pseudo-high C-filler (PHCF) composite films are constructed by introducing lean C-filler polymer phase on both sides of the high C-filler polymer phase. Not only does conductive structure of the high C-filler phase not transform, but the lean C-filler phase serves as both absorbing microwaves and supporting function. Strong interfacial compatibility and multi-level “zigzag” cracks synergistically enhance the mechanical stretchability with elongation at break of 200 ± 8%. Notably, its EMI shielding effectiveness reaches 31.8 dB with enhanced absorptivity (>0.2). Further, EMI shielding performance remains reliable after bending and stretching. This work offers a regulation strategy to upgrade EMI shielding materials for burgeoning stretchable, wearable and mini electronics.