Tailoring dielectric performance of P(VDF-CTFE) via incorporating thiophenol as a side chain

Poly(vinylidene fluoride) (PVDF) based fluoropolymers are typical ferroelectric polymers, and the large energy loss seriously hinders their applications for electric energy storage. To reduce the high dielectric loss induced by the polarization of ferroelectric phase, in this work, a series of P(VDF-DB)-graft-thiophenol copolymers (DB refers to CF[dbnd]CH double bond) are successfully synthesized under mild conditions using nucleophilic substitution reaction. The merits including the excellent miscibility of thiophenol with P(VDF-DB), and the promising insulating property of thiophenol segments are combined in the resulting copolymers. The results show that the relaxor ferroelectric behavior of P(VDF-DB) copolymer is effectively converted into linear-like dielectric by introducing a relatively low content of thiophenol. Meanwhile, the dielectric loss is significantly reduced, showing better dielectric energy storage performance than that of the pristine copolymer. This work provides a facile strategy for chemical modification and regulating the dielectric behavior of PVDF-based ferroelectric fluoropolymers.