Chirality induction in liquid crystalline side-chain polyethers prepared by copolymerization of oxiranes with mesogenic and non mesogenic groups

Copolymers prepared by anionic initiation from racemic or optically active styrene oxide and a racemic oxirane bearing cyanobiphenyl mesogenic group in the side chain are liquid crystalline when the content of the mesogenic monomer exceeds 60 mole %. Copolymers prepared from a mesogenic oxirane with a short spacer and racemic styrene oxide exhibit a nematic phase, while those prepared with optically active styrene oxide exhibit a cholesteric phase, thus indicating a transfer of chirality from the main chain towards the mesophase. Such a transfer of chirality is no more observed in the case of a copolymer prepared from a mesogenic oxirane with a long spacer.