Dielectric dispersion in 4'-n-Alkyl-4-cyanobiphyenyls

Abstract

The dispersion of b.epsipar in the frequency range of 1-10 MHz has been studied for 4'-n-alkyl-4-cyanobiphenyls (pentyl to octyl) at different temperatures in teh nematic phase. It is established for the first time that the relaxation frequency at a common relative temperature (TNI - T) for the successive homologues shows an alternation similar to that exhibited by the nematic-isotropic transition point or the orientational order parameter. The activation energy evaluated from the Arrhenius plot is found to be the same (sim 0.56 eV) for the compounds.