Dielectric Constants of Crystal and Amorphous Phases in Ferroelectric Polymers

概要

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Dielectric constants of crystal and amorphous phases in ferroelectric copolymers of vinylidene fluoride and trifluoroethylene are separated from the dielectric constant of samples including both phases by means of a two-phasemodel in which the depolarization field coefficient L=1/3 is assumed. Temperature dependence of the dielectric conslant of the ferroelectric crystal is not much different from that of a sample with a high degree of crystallinity, which increases during heating up to a ferroelectric-paraelectric phase transition temperature. On the other hand, the dielectric constant of the amorphous phase decreases with increasing temperature after an abrupt increase at the glass transition temperature. Although the tendency to decrease is explained as a property of liquid obeying Frohlich-Kirkwood theory, the rate of the decrease becomes steep with increasing temperature and deviates from the theory.
社団法人応用物理学会の論文
1991-12-15