Title :
TSDC study on VDF/TrFE copolymers
Author :
Faria, Roberto M. ; Neto, Joao M Guimaraes ; Figueiredo, Mariangola T.
Author_Institution :
Inst. de Fisica e Quimica de Sao Carlos, Brazil
Abstract :
TSDC measurements were carried out with samples of 60:40 and 70:30 molar ratios of VDF/TrFE (vinylidene fluoride-trifluoroethylene) copolymers. The 60(VDF):40(TrFE) copolymer presented a current peak around 90°C, associated with its ferroelectric-to-paraelectric (F-P) transition. The 70:30 copolymer also presented the F-P peak and, in addition, another peak at a lower temperature, identified as a phase transition between two ferroelectric phases. A model combining fast and slow polarization processes was developed to explain the TSDC curves. The fast process was connected to the phase transition, and the slow one was composed of the thermal depolarization of dipolar units of the β-phase crystallites and the variation of the pyroelectric current
Keywords :
dielectric polarisation; electrets; ferroelectric materials; ferroelectric transitions; polymer blends; thermally stimulated currents; TSDC; VDF/TrFE copolymers; current peak; electret; fast polarisation; ferroelectric-to-paraelectric; phase transition; slow polarization; thermal depolarization; vinylidene fluoride-trifluoroethylene; Cooling; Crystallization; Dielectric measurements; Ferroelectric materials; Heating; Noise measurement; Phase measurement; Polarization; Pyroelectricity; Temperature measurement;
Conference_Titel :
Electrets, 1991. (ISE 7) Proceedings., 7th International Symposium on (Cat. No.91CH3029-6)
Conference_Location :
Berlin
Print_ISBN :
0-7803-0112-9
DOI :
10.1109/ISE.1991.167260
