THERMAL-PROPERTIES AND ORIENTATIONAL BEHAVIOR OF IONIC LIQUID-CRYSTALLINE POLYMERS

The ionic liquid-crystalline polyethylenimines (LCPEIs) with ammonium ion moieties, the ion-complex-type liquid-crystalline polymer (ICLCP) and their low-mass model liquid crystals (LMLCs) were all synthesized. Their thermal properties and orientational behavior were studied. LCPEIs were prepared from polyethylenimine with the bromoalkyl mesogenic compound. ICLCP was obtained by ion exchange reaction between the polyanion and the cationic low-mass liquid-crystal. LCPEIs, ICLCP, and LMLCs exhibited enantiotropically thermotropic smectic phases. Ammonium ion moieties enhanced the thermal stability of the smectic phase, and were effective to form spontaneously the homeotropic structure in the smectic phase. The formed homeotropic structures of ionic liquid-crystalline polymers remained unaltered on cooling below the glass transition temperature. The smectic layer structures were studied by X-ray diffraction measurement and conoscopic observation. In the smectic layers of LCPEIs, ICLCP, and LMLCs, the neighboring mesogenic groups overlapped with each other, and the ammonium ion moieties independently aggregated to form a sublayer.