DIELECTRIC BEHAVIOR OF POLY(VINYLIDENE FLUORIDE)/GRAPHENE COMPOSITES WITH LOW PERCOLATION THRESHOLD

摘要

Poly(vinylidene fluoride) (PVDF)/graphene composite was successfully fabricated by a solution-cast and hot-pressing method. The composite material with graphene as conductive filler exhibited a very low percolation threshold (0.0018 volume fraction), but the dielectric constant was enhanced significantly. The largest dielectric constant of 7940 was observed for the PVDF/graphene composite with 0.0177 graphene volume fraction at 100 Hz. Large enhancements of the ac conductivity and loss tangent were also observed for the composites with graphene content near the percolation threshold. The percolation theory was used to explain the dielectric behavior of the composite.