▎ 摘　　要

A novel sandwich structure based on few-layer graphene nanosheets (FLGs) composed of functionalized porous graphene, pristine graphene and functionalized porous graphene is proposed. After one-step alkaline-mediated hydrothermal treatment, the outmost layers of FLGs are etched to porous structure. Sandwich FLGs/poly(vinylidene fluoride) (PVDF) composites are fabricated and the composites show excellent dielectric properties among carbon-based fillers/PVDF composites. Owing to the unique semiconductor/conductor/semiconductor structure, theoretical analysis indicates that the dielectric constant of the sandwich FLGs/PVDF composites can be as high as 10(5). Our findings provide a novel strategy to fabricate high dielectric performance graphene based composites and the process is simple, low-cost and environmentally friendly. (c) 2013 Elsevier Ltd. All rights reserved.