The effect of geometrical shape and molecular rigidity on mesomorphism

A novel nonlinear homologous series RO-C6H4-CH=CH-COO-C6H4 (meta) -CO-CH=CH-C6H4-OC12H25(n) (para) consisting of three phenyl rings, two central bridges -CH=CH-COO- and -CO-CH=CH- as well as -OR and -OC12H25(n) as flexible and constant terminal end groups respectively. The object in view is aimed to understand and establish the effect of molecular structure on LC properties of nonlinear inverted "V" shaped molecules. Novel homologous series consists of thirteen homologues. Transition temperatures and textures were determined by polarizing optical microscopy (POM) equipped with a heating stage. Textures of nematic phases are threaded or schlieren and that of a smectic phases are of the type-A or C. Transition curves of a phase diagram behaved in a normal manner. Sm-N and N-I transition curves exhibited odd-even effect. Analytical, Thermal and Spectral data confirms the molecular structure of homologues.