Flexoelectric effect in PVDF-based polymers

Flexoelectricity is a gradient electromechanical coupling effect that exists in all dielectrics and is important for the understanding of a variety of gradient-induced physical phenomena and the design of new electromechanical devices. At present, the flexoelectric effect in polymer materials has not been well studied. In this work, thick rectangular poly(vinylidene fluoride) (PVDF)-based polymer samples were fabricated and the flexoelectric coefficient was measured. Our results show that the flexoelectric coefficient of the PVDF, which is on the order of several nC/m, is more than twice higher than that of P(VDF-CTFE) and P(VDF-HFP) polymers. All these materials exhibited a non-polar α phase, but the copolymers showed much smaller crystallinity values than the PVDF homopolymer. The difference in the flexoelectric response in these polymers is believed to be related to the crystallinity of the polymers.