SIDE-CHAIN TYPE LIQUID-CRYSTALLINE POLYETHERS .2. EFFECTS OF MESOGENIC MOIETIES ON THE THERMAL-PROPERTIES AND THEIR SELF-ASSEMBLY BEHAVIOR

A series of polyethers having mesogenic moieties connected to the backbone without flexible spacer in the side-chain were prepared by ring-opening polymerization of the corresponding glycidyl ether derivatives containing various mesogens. As the mesogenic side-chains, tolan and phenylene units with alkoxy or alkoxycarbonyl groups were introduced and compared with biphenyl type mesogens. The polyether with tolan derivative having butoxy group as the side-chain end exhibited two kinds of highly ordered smectic phases. On the other hand, in the case of biphenyl or tolan as the rigid-core, introduction of ester group as an end-group decreased the thermal stability of liquid-crystalline phase as compared with the case of alkoxy group as the end group. The polyethers with the p-alkoxyphenyl group in the side-chain exhibited a smectic A phase which formed a bilayer structure, while no mesophase was observed for those having the p-alkoxycarbonylphenyl group in the side-chain. The self-assembly of bilayer structures, which consist of hydrophilic layer (polyether backbone) and hydrophobic layer (side-chain), might be responsible for the appearance of liquid-crystallinity in such polyethers whose mesogen consists only of a simple phenylene ring.