Dielectric relaxation behaviour of the side group liquid-crystalline polyacrylates having a segmented spacer

Abstract

The dielectric relaxation behaviour and the alignment property of two kinds of liquid-crystalline (LC) polyacrylates, P-3EO-C6 and P-3EO-C11, having a segmented spacer, which consisted of binary components of an oligo(ethylene oxide) segment and an alkylene segment, was investigated to clarify the effect of the spacer structure on these properties. For P-3EO-C6 showing a glassy behaviour, δ-relaxation was observed in the lower temperature region compared with the case of an ordinary liquid-crystalline polymer with mesogenic side groups (SGLCP). The relaxation behaviour of the samples of both P-3EO-C6 and P-3EO-C11 indicated characteristically low values of ΔG^‡. The microphase separation was supposed in the case of P-3EO-C11 to have a long alkylene segment. For the alignment behaviour of P-3EO-C6, the fully aligned sample could be achieved by applying an electric field. From these results, the advantage of the segmented spacer as an accelerator of the motion of a mesogenic group has been discussed in this paper.