Facile preparation of graphene film and sandwiched flexible poly(arylene ether nitrile)/graphene composite films with high EMI shielding efficiency

Abstract

From the industrial grade graphene nanosheet (GNS) powder, the flexible, ultra-thin and freestanding graphene films are prepared using ultrasonic-assisted dispersion and suction filtration. The sandwiched composites films are prepared by layer-by-layer assembly using poly(arylene ether nitrile) (PEN) as polymer matrix. The strong Π···Π interaction pulls the graphene sheets together in a face-to-face way and they assembly into flexible graphene films. High electromagnetic interference shielding effectiveness (EMI SE) is shown due to multiple internal reflection and absorption inside the porous graphene films. A 3 μm thick graphene film shows EMI SE over 20 dB, specific SE (SE/density/thickness, SSE/t) of 72967 dB·cm2/g and absorption ratio over 92%. Moreover, the highest EMI SE of 77 dB is reached by sandwiching 3-layers of graphene films with PEN, and the composites films exhibit high flexibility, high tensile strength over 40 MPa and glass transition temperature of 185 °C.