Synthesis and properties of polythiophene derivatives with ferroelectric liquid crystalline substituents

Chiroptical liquid crystalline (LC) substituent with fluorine-containing asymmetric moiety was introduced into the 3-position of thiophene ring. Polymerizations of 2,5-dibrominated thiophene monomers were carried out through dehalogenative polycondensations. The polymers showed several types of smectic phases in the heating and cooling processes. Besides, one of the polymers exhibited a striated fan-shaped texture in polarizing optical microscope. This is attributed to a formation of chiral smectic C phase, which is indispensable for ferroelectricity.