LIQUID-CRYSTALLINE SIDE-GROUP POLYESTERS WITH DEFINITE LENGTHS OF FLEXIBLE SPACERS IN THE MAIN-CHAIN

Liquid-crystalline polymalonates with a definite distance between the contact points of two neighbouring side groups were synthesized. The m esogenic group is azobenzene with a terminal nitro-substituent acting as an indicator for dielectric measurements. The influence of the numb er of methylene groups in the main chain on the polymorphism and the d ielectric behaviour has been investigated. Generally, the thermal stab ility of the mesophases decreases when the main chain spacer becomes l onger. The relaxation frequency for the reorientation of the mesogenic side group around the short axis increases with increasing number of methylene groups in the main chain in both, the isotropic and liquid-c rystalline phases.