Synthesis and properties of polythiophene derivatives with liquid crystalline substituents

We have synthesized a novel liquid crystalline conductive polythiophene derivative through dehalogenative polycondensation of 2,5-dibrominated thiophene monomer with a liquid crystalline substituent at 3-position of thiophene ring. The polymer is fusible and soluble in some organic solvents and has weight-average and number-average molecular weights of 8 × 104 and 4 × 104, respectively. Polarizing microscope of the polymer exhibits schlieren and droplet textures in the cooling process of 110∼130°C, demonstrating a formation of monotropic nematic liquid crystalline phase in the polymer.