Modified sepiolite/PVDF-HFP composite film with enhanced piezoelectric and dielectric properties

Flexible film with both piezoelectric and dielectric properties is considered to be a potential candidate for the energy conversion and storage devices. In this study, the Li+ and H2O modified sepiolite/poly(vinylidene fluoride-co-hexafluoropropylene) (LiSEP-H2O/PVDF-HFP) composite films with both good piezoelectric and dielectric properties were prepared by traditional coating process. When the H2O content was 13 wt %, the LiSEP-H2O/PVDF-HFP composite exhibited high d(33) of 32 and dielectric constant of 48. Moreover, the effects of the Li+ and adsorbed H2O on the d(33), F(beta), dielectric constant, short-circuit currents were discussed. The adsorbed H2O enhanced the beta-phase by the hydrogen bonds and Li+ improved the polarization to realize the composite film with increased piezoelectric and dielectric properties respectively. We expected the common modification to lead other clay minerals realizing the future applications in the adjustment of composites' electric properties. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48412.