Mesomorphism dependence on molecular rigidity and flexibility

A novel homologous series of liquid crystalline properties is synthesized and studied with a view to understand the effect of molecular structure on its thermotropic properties. Novel homologous series consisted of thirteen homologs. All the homologs are enantiotropically smectogenic with absence of nematic property even in the monotropic condition. Textures of the homologs as observed through an optical hot stage polarizing microscopy. The mesophase temperature range vary minimum from 6.0°C to a maximum 37.0°C at the methyloxy and propyloxy derivatives of a series respectively with its thermal stability (Sm–I) 127.0°C. Transition curves of a phase diagram behaved in normal manner. Odd–even effect is observed for Sm–I transition curve.