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

ABSTRACT 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 H 2 O modified sepiolite/poly(vinylidene fluoride‐ co ‐hexafluoropropylene) (LiSEP‐H 2 O/PVDF‐HFP) composite films with both good piezoelectric and dielectric properties were prepared by traditional coating process. When the H 2 O content was 13 wt %, the LiSEP‐H 2 O/PVDF‐HFP composite exhibited high d 33 of 32 and dielectric constant of 48. Moreover, the effects of the Li + and adsorbed H 2 O on the d 33 , F(β), dielectric constant, short‐circuit currents were discussed. The adsorbed H 2 O enhanced the β‐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. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48412.