Influence of spacer length on the dielectric relaxation of a side chain liquid crystal polymer

Abstract

The dielectric relaxation study on a set of polyvinylether based cyanobiphenyl side chain liquid crystal polymers with three different alkyl spacer lengths of 7, 9, and 11 shows that the spacer decouples the motion of the mesogen from the polymer backbone so that both the low-frequency δ process and the high-frequency α process of the side group have been detected in smectic A phase. At a given temperature the relaxation frequency increases with spacer length for the α process. This trend is also observed for the λ process except for the longest spacer length.