Linear-like dielectric behavior and low energy loss achieved in poly(ethyl methacrylate) modified poly(vinylidene-co-trifluoroethylene)

To realize linear-like dielectric characteristics in normal ferroelectric poly(vinylidene-co-trifluoroethylene) (P(VDF-TrFE)), poly(ethyl methacrylate) (PEMA) was grafted onto poly(vinylidene fluoride-co-trifluoroethylene-co- chlorotrifluoroethylene) as side chains. The introduction of rigid PEMA segments resulted in the decreased crystallinity, crystal and ferroelectric domain size. As a result, reduced dielectric loss and improved modulus, therefore enhanced breakdown strength was obtained in the graft copolymers. Moreover, low energy loss (about 16.6%) and relatively high energy density (19.3 J cm^-3) under high electric field (675 MV m^-1) was achieved since the hysteresis induced by the ferroelectric relaxation of P(VDF-TrFE) has been completely eliminated.