Photosensitive phasmid-like liquid crystalline materials with unusual mesomorphic behavior

Abstract

We report on the synthesis and mesomorphic properties of five new series of azo functionalized phasmid-like compounds formed by covalent bonding. They consist of both symmetric and non-symmetric molecules. Most of these compounds are found to be liquid crystalline, with unusual behavior. They exhibit mainly nematic, columnar and smectic mesophases. In addition to these phases, in few cases, we observed some higher order mesophases as well. The nature of these mesophases is investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. We obtained unconventional XRD patterns for the nematic phase in some of these compounds. Based on the experimental results, we propose a model for the molecular arrangement in the columnar phase to be center rectangular. Dielectric and optical transmission measurements in the mesophases of one of the representative compounds are also reported. We have made a qualitative investigation into the photosensitivity of the mesophases of one of these compounds.