| Abstract: | Novel liquid crystalline (LC) acrylate side group copolymers, which consist of nematogenic phenyl 4-methoxybenzoate acrylate monomer (A) and novel chiral binaphthyl (BN) methacrylate monomers (MB-n) have been synthesized. The copolymers prepared differ in the spacer lengths of MB-n (n 3,5,11) and in their compositions. The homopolymers of the three new chiral binaphthyl monomers MB-n were also prepared. Copolymers with a low concentration of binaphthyl monomer units (less than 16 mol%) display a cholesteric mesophase. The induced chirality in the polymers is due to atropoisomerism (C2-symmetry) of the molecules. The helical twisting powers (beta), caused by the atropoisomeric units in the synthesized copolymers, were determined, and their temperature dependencies studied. The unusually high negative temperature coefficient of beta observed above the glass transition temperature is explained in terms of conformational changes of the BN molecules in the copolymers. |
