Dielectric Relaxation and Conformational Disorder in P(VDF/TrFE)(50/50) Copolymer Films Irradiated with Fast Electrons.

Relaxor-like dielectric response was observed in ferroelectric P(VDF/TrFE)(50/50) films irradiated with 1.0 and 1.5 MeV electrons and related to the results of ESR, IR and NIR Raman studies of radiation damage of the copolymer. The origin of the strong dielectric dispersion below the permittivity maximum and the frequency dependence of the temperature of ℇ max is rather complex: radiation-induced downward shift of the Curie point results in an overlapping of the dielectric anomalies at T C and at the glass transition and moreover, the dispersion is enhanced by the contribution of polar clusters consisting in short-range coherence of trans conformations. The single and conjugated C=C bonds, appearing as a result of the decay of free radicals created by incident electrons, cut ferroelectric all-trans conformation of the copolymer chains into polar clusters of short trans coherence. [ABSTRACT FROM AUTHOR]