Lightweight, compressible, and stretchable composite foams for ultra-efficient and high-stable electromagnetic interference shielding materials

Lightweight, flexible, high-stable and ultra-efficient electromagnetic shielding materials are the extremely desired materials for electronic devices and products. In this paper, a lightweight, compressible, and stretchable ferric trichloride (FeCl3)/carbon nanotubes (CNTs)/polyvinyl pyrrolidone (PVP)/polyurethane (PU) composite foam with ultra-efficient electromagnetic interference shielding is fabricated by the chemical foaming method and subsequent ultrasound assisted loading of conductive layer onto PU skeleton. The as-prepared FeCl3/CNTs/PVP/PU composite foam with a density of 40 mg/cm3 possesses ultrahigh electromagnetic interference shielding properties at X-band (∼91.5 dB at 12.4 GHz) attributed to the unique porous structure to dissipate electromagnetic wave as well as the synergistic shielding effect of FeCl3 and CNTs. More importantly, the ultra-efficient electromagnetic shielding performance can still remain even after subjected to water-washing, long-term cyclic compression or high/low temperature treatment because the addition of PVP can greatly enhance the interaction between CNTs and PU skeleton. The current work proposes a simple and scalable method to fabricate ultra-efficient electromagnetic interference shielding materials for wearable and portable electronic devices.