Measurement of the microwave effective permittivity in tensile-strained polyvinylidene difluoride trifluoroethylene filled with graphene

We report an interesting effect in the form of a rise (up to 13%) in the permittivity of graphene (GE) filled polyvinylidene difluoride trifluoroethylene (P(VDF-TrFE)) subjected to a small uniaxial deformation (up to 7% in the principal direction). Our findings differ from GE-PVDF homopolymer samples that show a decrease of permittivity upon elongation. We argue that the VDF content which controls the spontaneous polarization has a profound effect on the charge storage through the addition of interface density by the GE phase. (C) 2014 AIP Publishing LLC