Both nonionic liquid-crystalline side-chain polymer [P(A-CH3)] and ionic family [P(A-CH3/CH3I)] of P(A-CH3) were prepared. Nonionic P(A-CH3), having an alkylamine spacer, exhibited solid-smectic and smectic-isotropic phase transitions. Ionic P(A-CH3/CH3I), having an alkylammonium spacer, showed glassy-smectic and smectic-isotropic phase transitions. Ionic P(A-CH3/CH3I) exhibited the enhanced thermal stability by the aggregation of ammonium ions formed by Coulomb's force in comparison with nonionic P(A-CH3). The enhanced thermal stability in ionic families was also concluded from experimental results obtained for nonionic and ionic low molecular weight liquid-crystalline compounds corresponding to mesogenic side groups of P(A-CH3) and P(A-CH3/CH3I).
