Induced Smectic Phases in Binary Mixtures of a Compound Having a Weakly Polar End Group and a Compound Having a Non-polar End Group

Abstract

We have studied the phase diagram of binary mixtures of 4′-n-heptyl-4-bromobiphenyl (a non-mesomorphic compound having a weakly polar terminal group) and 4,4′-di-n-heptyloxyazoxybenzene (a mesomorphic compound having a non-polar terminal group). The mixture exhibits an induced smectic A phase over a wide composition range and also an induced smectic E phase over a narrow composition range. X-ray studies show that the molecular arrangement in the smectic A phase is monolayer for all compositions.

We have also observed defects of strength ±pL2 and ±pL3/2 in the nematic phase in a certain composition range of the mixture.