Graphene/poly(vinylidene fluoride) dielectric composites with polydopamine as interface layers

Abstract

A poly(vinylidene fluoride) (PVDF) nanocomposite incorporated with polydopamine-coated reduced graphene oxide (rGO@PDOPA) nanosheets has been developed with high dielectric permittivity and low loss for electricity storage applications. Structural analysis indicates that PDOPA was successfully anchored onto rGOs through non-covalent linkage under mild conditions. The presence of PDOPA layer between rGO and PVDF can not only prevent the agglomeration and direct contact of original rGOs but also enhance the interaction between PVDF and rGO and microcapacitor formation. Compared to rGO/PVDF composites, higher dielectric permittivity and lower loss factor were achieved simultaneously in rGO@PDOPA/PVDF nanocomposites at low and moderate frequencies. The PDOPA interface layers are effective in modifying the dielectric characteristics of the composites to increase the dielectric permittivity without the introduction of loss mechanisms. This study demonstrates that PDOPA is an ideal interface layer for the development of new percolative dielectric composites with high dielectric permittivity and low loss.