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Etude par diffusion Raman de la transition ferro‐paraelectrique dans les copolymeres de fluorure de vinylidene et de trifluorethylene p(VF 2 ‐TrFE)
Author(s) -
Abénoza Michel,
Armengaud Alain,
Chouh Saíd
Publication year - 1988
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19880200118
Subject(s) - raman spectroscopy , ferroelectricity , curie temperature , phase transition , dielectric , chemistry , crystallography , materials science , condensed matter physics , physics , optics , ferromagnetism , optoelectronics
The ferro‐paraelectric transition in the 80/20 and 70/30 mol/mol copolymer of vinylidene fluoride and trifluoroethylene is studied by Raman spectroscopy. The Curie transition temperature is depending on the composition and the orientation of the material. At the transition drastic modifications occur in the observed Raman spectra: vanishing of the 842, 1300 and 1350 cm −1 Raman band intensities; strong variation of the band polarizations, this change being not completely reversible when lowering the temperature. This study shows that the Raman spectra evolution is consistent with a conformational change between the extended “all trans” form and a rich gauche‐sequence configuration. Moreover, polarization changes along the studied temperature cycle show that the paraelectric phase is highly disordered and that after the cycle is carried out a part of this chain disorientation remains in the ferroelectric phase.