MOLECULAR-DYNAMICS SIMULATION OF MAIN-CHAIN LIQUID-CRYSTALLINE POLYMERS

Molecular dynamics simulations of a model main-chain liquid crystallin e polymer (LCP) and of a low molecular weight analogue have been carri ed out using an efficient parallel algorithm. A main-chain LCP is form ed with the help of Gay-Berne mesogenic units connected to each other through flexible methylene spacers. We have studied the effect of vary ing the spacer length, and have examined the region of the isotropic-l iquid crystalline transition. Our preliminary results indicate that li quid crystalline ordering may occur spontaneously on lowering the temp erature, and that odd-even dependences of thermodynamic properties on spacer length occur, in agreement with existing experiments. Local ori entational time correlation functions, as well as local translational mobility, have been studied both for the mesogenic elements and the bo nds in the flexible spacer. The anisotropy of both orientational and t ranslational local dynamical properties have been compared viith theor etical predictions and with Brownian dynamics results for a freely joi nted chain in a liquid crystalline orienting field.