A thermotropic biaxial nematic liquid crystal

Abstract

Optical studies have been carried out on a nematogenic copper complex, which incorporates the features of both rod-like and disk-like molecules. Conoscopic figures are presented demonstrating (i) the occurrence of a biaxial nematic phase in the pure complex, (ii) the uniaxial-biaxial (N_a-N_b) transition in binary mixtures, and (iii) the temperature variation of the biaxiality near this transition. The I-N_a-N_b phase diagram has been studied for the binary system.