Ferroelectric and piezoelectric properties of a quenched poly(vinylidene fluoride-trifluoroethylene) copolymer

✍ Scribed by M. C. Christie; J. I. Scheinbeim; B. A. Newman

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 198 KB
• Volume: 35
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19971130)35:16<2671::aid-polb10>3.0.co;2-6

✦ Synopsis

The ferroelectric and piezoelectric properties of melt-quenched unoriented poly(vinylidene fluoride-trifluoroethylene) (73 : 27) copolymer films as a function of the number of poling cycles have been studied. The investigation revealed that quenched films exhibit a decrease in D-E hysteresis behavior as the number of poling cycles increases when the samples are poled at room temperature. Corresponding decreases in remanent polarization, Pr, as well as small increases in the coercive field, Ec, were observed as the material was subjected to successive poling cycles. The piezoelectric coefficients, d 31 and e 31 , also decreased as the number of poling cycles increased. In addition, a clear reduction in the ''apparent'' Curie transition temperature between unpoled and poled material was observed. Preliminary evidence indicates that films quenched from the melt to below T c do not form a stable ferroelectric crystal phase as previously believed.