TIME AND POLING HISTORY DEPENDENT ENERGY STORAGE AND DISCHARGE BEHAVIORS IN POLY(VINYLIDENE FLUORIDE-CO-HEXAFLUOROPROPYLENE) RANDOM COPOLYMERS

作     者：Fang-xiao Guan Jing Wang Ji-lin Pan Qing Wang Lei Zhu 

作者机构：Polymer Program Institute of Materials Science and Department of Chemical Materials and Biomolecular Engineering University of Connecticut Storrs Connecticut 06269-3136 USA b Department of Materials Science and Engineering Pennsylvania State University University Park Pennsylvania 16802 USA Department of Maeromolecular Science and Engineering Case Western Reserve University Cleveland Ohio 44106-7202 USA 

出 版 物：《Chinese Journal of Polymer Science》 (高分子科学（英文版）)

年 卷 期：2011年第29卷第1期

页      面：65-80页

核心收录：

学科分类：081704[工学-应用化学] 0808[工学-电气工程] 08[工学] 0817[工学-化学工程与技术] 081701[工学-化学工程] 

基　　金：supported by ONR(N00014-05-1-0338) NSF(DMR-0907580) 

主　　题：P(VDF-HFP) random copolymer Charging and discharging behaviors Time and poling history dependence Dipole switching Compensation polarization. 

摘      要：We studied cycle time （0.01-10 s with triangular input waves） and poling history （continuous versus fresh poling） dependent electric energy storage and discharge behaviors in poly（vinylidene fluoride-co-hexafluoropropylene） [P（VDF- HFP）] films using the electric displacement -- the electric field （D-E） hysteresis loop measurements. Since the permanent dipoles in PVDF are orientational in nature, it is generally considered that both charging and discharging processes should be time and poling history dependent. Intriguingly, our experimental results showed that the charging process depended heavily on the cycle time and the prior poling history, and thus the D-E hysteresis loops had different shapes accordingly. However, the discharged energy density did not change no matter how the D-E loop shape varied due to different measurements. This experimental result could be explained in terms of reversible and irreversible polarizations. The reversible polarization could be charged and discharged fairly quickly （〈 5 ms for each process）, while the irreversible polarization depended heavily on the poling time and the prior poling history. This study suggests that it is only meaningful to compare the discharged energy density for PVDF and its copolymer films when different cycle times and poling histories are used.