Liquid-crystalline polymers containing heterocycloalkane mesogenic groups. 5. Synthesis of biphasic chiral smectic polysiloxanes containing 2,5-disubstituted-1,3-dioxane- and 2,5-disubstituted-1,3,2-dioxaborinane-based mesogenic groups

TLDR: In this paper, the synthesis of side-chain liquid crystalline polysiloxanes containing chiral mesogenic side-groups is presented, which are biphasic systems resembling the behavior of phase separated graft copolymers, i.e., they exhibit a micro-phase separated morphology containing main-chain and sidechain domains.

Abstract: : The synthesis of side-chain liquid crystalline polysiloxanes containing chiral mesogenic side-groups, is presented. Differential scanning calorimetry and optical polarization microscopy revealed chiral smectic mesomorphism for all polymers. The last two polymers present also a chiral smectic-C mesophase. All copolymers exhibit two glass transition temperatures; one due to the independent motion of the main chain, the other due to the cooperative but independent motion of the side-groups. Therefore, these liquid crystalline copolymers are biphasic systems resembling the behavior of phase separated graft copolymers, i.e., they exhibit a micro-phase separated morphology containing main-chain and side-chain domains.