Defected poly(vinylidene fluoride) with enhanced piezoelectricity via liquid crystal small molecules doping

A poly(vinylidene fluoride)-based composite film with higher piezoelectric properties was prepared by the solvent mixing method of adding liquid crystal small molecules to create defects among polyvinylidene fluoride (PVDF) molecular chains. The composite obtained by simple uniaxial stretching and thermal polarization exhibits higher piezoelectric properties (d 33 = 29.0 pC/N) than neat PVDF (d 33 = 24.3 pC/N). The defects reduce the grain size of PVDF to some extent, thus reducing the coercivity field of PVDF from 64.6 to 58.1 MV/m. This strategy could endow PVDF with higher piezoelectric coefficient and lower polarization field, which is attractive for piezoelectric applications.