Structure of Nematic Side Chain Polymers

Abstract

Systematic investigations of the past years have proved that the structures of the liquid crystalline phases of liquid crystalline (l.c.) side chain polymers are similar to the structures of conventional low molar mass liquid crystals (1.1c). Nematic and cho].esteric phases as well as S_A and S_C phases have been clearly identified ^1,2. The systematic realization of l.c. side chain polymers, however, requires a flexible linkage of the rigid mesogenic moieties to the polymer backbone via a flexible spacer. The flexible spacer more or less decouples the motions of the rod-like side chains and the backbone. Two extremes are conceivable. With a long flexible spacer the main chain does not influence the anisotropic packing of the side chains. In case of no flexible spacer, motions of the mesogenic side groups are directly correlated with the motions of the chain segments, normally preventing the l.c. state.