Veena Prasad
Centre for Nano and Soft Matter Sciences, India
Title: Azo substituted achiral bent-core liquid crystals: photo-induced studies in B7 and B2 mesophases
Biography
Biography: Veena Prasad
Abstract
A new surge of activity in the field of ferro-/antiferro-electric liquid crystals was prompted in 1996, by the observation of ferroelectric switching in achiral bent-core compounds. Later, several such compounds exhibiting electro-optically switchable mesophases were reported. The first photochromic azo functionalised bent-core liquid crystals were reported by us in 2001. The reversible photo-induced effects observed (Veena and Jakli, in 2004), in transition temperatures and electrio-optical switching properties of the mesophases exhibited by these compounds, have added a new dimension to the exciting field of bent-core liquid crystals. Thus, we continued our investigations on such azo functionalised compounds, from various aspects. In this presentation, I will be describing three structural variants of azo substituted achiral bent-core compounds constituting of symmetrical and non-symmetrical molecules. It was found that the non-symmetrical molecules are more conducive to mesomorphism than the symmetrical ones. We observed B1 (Colr), B2 (SmCAPA) and B7 mesophases in these compounds. The B7 mesophase was found to have a modulated layer structure. We also report for the first time, the photo-induced studies in the B7 mesophase and make a comparison of these results with those obtained in a B2 mesophase. From our studies, we observed that these effects are more profound in the case of B7 mesophase when compared to the B2 mesophase, in such systems.