Dielectric relaxation and the mobility of mesogenic groups in cholesterol-containing liquid crystal polymers with decouplings of different lenght

Abstract

Dielectric relaxation processes in liquid crystal polymers with mesogenic cholesterol groups in the side chain are studied at temperatures of - 170–230°C at frequencies of 0.06–300kHz. At low temperatures three tan δ maxima are observed with all the polymers studied, and these are assigned to local forms of motion of the two COO groups in the side chains. At high temperatures the maximum of the losses, irrespective of the frequency, determines the temperature of the transition into the isotropic state. In the region of the mesomorphic state, two relaxation processes are observed close to the glass transition temperature, which are distinguished by the high values of the activation energy, and also structural transitions.