Open AccessFerroelectric Polymers Exhibiting Negative Longitudinal Piezoelectric Coefficient: Progress and Prospects
Author(s) -
Liu Yang,
Wang Qing
Publication year - 2020
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201902468
Subject(s) - piezoelectricity , electrostriction , materials science , ferroelectricity , polymer , ferroelectric polymers , amorphous solid , piezoelectric coefficient , composite material , copolymer , crystallography , chemistry , optoelectronics , dielectric
Piezoelectric polymers are well‐recognized to hold great promise for a wide range of flexible, wearable, and biocompatible applications. Among the known piezoelectric polymers, ferroelectric polymers represented by poly(vinylidene fluoride) and its copolymer poly(vinylidene fluoride‐ co ‐trifluoroethylene) possess the best piezoelectric coefficients. However, the physical origin of negative longitudinal piezoelectric coefficients occurring in the polymers remains elusive. To address this long‐standing challenge, several theoretical models proposed over the past decades, which are controversial in nature, have been revisited and reviewed. It is concluded that negative longitudinal piezoelectric coefficients arise from the negative longitudinal electrostriction in the crystalline domain of the polymers, independent of amorphous and crystalline‐amorphous interfacial regions. The crystalline origin of piezoelectricity offers unprecedented opportunities to improve electromechanical properties of polymers via structural engineering, i.e., design of morphotropic phase boundaries in ferroelectric polymers.