LIQUID-CRYSTALLINE SILSESQUIOXANES

Liquid-crystalline silsesquioxanes were synthesized by combining mesogens with spherical silsesquioxanes. Most of the synthesized compounds exhibit smectic phases. Lateral connection of a mesogen results in a nematic phase. All phases are optical uniaxial positive, i.e. calamitic structures are favoured. LC-silsesquioxanes represent a new group of liquid-crystalline side-chain polymers with backbones ranging from centrosymmetric cage like structures of siloxanes or heterosiloxanes to linear ladder structures. They can be considered as the link between the linear side-chain polymers and surface treated silica or quartz.