Fast discharge speed in poly(vinylidene fluoride) graft copolymer dielectric films achieved by confined ferroelectricity

Although a high electric energy density was recently reported for defect-modified poly(vinylidene fluoride) (PVDF) copolymers at millisecond discharge, they usually deliver less energy at a high pulse rate. In this letter, a low loss polystyrene (PS) was grafted as side chains onto the P(VDF-chlorotrifluoroethylene) main chain. After PVDF crystallization, dielectric PS side chains were segregated to the crystalline-amorphous interface, forming a finite confinement layer for ferroelectric PVDF crystals. We speculated that less space charge was induced during electric poling because of the nanoscale confinement effect. Consequently, a fast discharge speed and a relatively high energy density were achieved.