▎ 摘　　要

In this work, a hydrosoluble matrix is used for the first time to prepare flexible membranous composites, in order to improve their environmental friendliness and simplify the processing. Modified graphene (GR) sheets are distributed in polyvinyl alcohol (PVA) solution to achieve flexible GR/PVA metacomposites. As graphene content increases, an interconnected graphene network is eventually formed among the PVA matrix, and the resulting composites present a conductor-like behavior. Interestingly, the Drude-like negative permittivity is obtained in the composites with 20 wt% graphene, which is ascribed to the plasma oscillation. Meanwhile, the absolute values of negative permittivity decrease by several orders of magnitude due to the moderate electron density of graphene. It is demonstrated that the negative permittivity is dependent on the inductive character. This work provides a novel and versatile approach based on water-soluble matrices to prepare flexible membranous metacomposites, which can be applied in wearable cloaking, thin-film capacitors, and flexible and stretchable devices.