Somen Debnath, featured ILCC liquid crystal artist, September 2014

Somen Debnath is a UGC research fellow doing his Ph.D programme with Prof. Nandiraju V S Rao, Department of Chemistry, Assam University, Silchar, India. He does synthesis and characterization of achiral four-ring bent-core compounds, studying the influence of substituents on the mesomorphism and optical properties of these four ring compounds. Some of the bent compounds and their complexes exhibit nematic and smectic phases with unusual (Polarizing Optical Microscopy (POM) textures. He obtained his B. Sc (2006) degree from Karimganj College, Assam, India and M. Sc (2008) from Assam University, Silchar, India. He already has completed his doctoral thesis under the title: “Influence of substituents and linking moiety on chirality in achiral bent core mesogens: synthesis and characterization".

His research interest lies in the synthesis and studies of electric-field responsive liquid crystals, chiral nematic liquid crystals, polarization modulated B7 phases for the design of electro-optical materials.

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Dendritic growth of columnar phase exhibited by a four ring bent core compound on slow cooling from isotropic liquid. The image is taken in a homogeneous cell of 3.2μm thickness under 20X magnification at 98.3°C, which on further cooling exhibits polarization splay modulated and layer undulated B1Rev/Tilted phase variants. The picture was taken on a Nikon Polarising microscope (Nikon optiphot-2-pol) attached with Instec STC 200 hot stage and Nikon Digital sight DS-Fi1 digital camera. The image height is about 100 microns.

Jury comment: In the past eight months, we saw different phase of bent-core LCs. They usually show beautiful colors due to biaxial optical axis. This month let us go back to the columnar phase on homogeneous alignment.