Synthesis and thermal properties of side-chain type liquid crystalline polymers containing carbazolyl group

New side-chain type liquid cvystalline (LC) polymers containing( carbazolyl group were synthesized. These polymers contain carbazolyl derivatives, 2(9-methyl-carbazolyl) benzoate as a part of mesogen, and polymethacrylate, polyester, polymethylsiloxane, polymaleimides as a polymer backbone. The mesomorphic behavior and phase transition temperatures of these polymers were characterized by polarizing optical microscopy and differential scanning calorimetry (DSC) measurements. The LC phases were revealed by X-ray diffraction measurements. Polymethacrylate containing non-substituted carbazolyl moiety exhibited a smectic A(1) phase. Polymethacrylates containing nitro-substituted carbazolyl moiety exhibited a smectic A(d) phase. The latter one has the high phase transition temperatures and the wide mesomorphic temperature ranges. Polyester derivatives did not show typical LC phases. Polysiloxane derivatives exhibited a smectic A(1) phase. The siloxane ring would contribute the stability of the LC phase. Polymaleimide derivative with. longer methylene unit in the side chain exhibited a smectic C phase, while polymaleimide derivative with shorter methylene unit in the side chain showed a nematic phase.