Flexible few-layered graphene/poly vinyl alcohol composite sheets: synthesis, characterization and EMI shielding in X-band through the absorption mechanism

摘要

1 mm thick flexible few-layered graphene (FLG)/poly vinyl alcohol (PVA) composite sheets containing 0.1 and 0.5 vol.% of FLG are prepared using an easy solution mixing process followed by a simple casting process. As-synthesized FLG is used as the filler. The morphology, structure and phase characteristics clearly showed the formation of a composite. A maximum electromagnetic interference (EMI) shielding effectiveness (SE) of similar to 19.5 dB (in the X-band, 8.2-12.4 GHz) was obtained in the case of the composite with 0.5 vol.% of FLG. Absorption is found to be the dominant mechanism for EMI shielding. The high EMI SE is attributed to the network-like features formed by FLG in the PVA matrix. EMI SE and absorption are understood by analyzing the dielectric behaviour, ac-conductivity and transparency to visible light of the composite sheets.