Rajdeep Deb presently works in the National Institute of Technology-Silchar, India as a teaching assistant in Department of Chemistry for UG and PG courses. Prior joining there he worked in the Liquid crystal Material Research Center (LCMRC), University of Colorado at Boulder being ICAM-I2CAM Junior Exchange Awardee. Here he studied the most spectacular defects and structures in B7 phase (such as spirals, ribbons, checkerboard …) using various experimental techniques in Prof. Noel A Clark and Prof. Ivan I Smalyukh’s Lab.

As a graduate research assistant he worked in Prof. Nandiraju V S Rao’s group in Department of Chemistry, Assam University, India. His doctoral dissertation work is directed toward tailoring liquid crystal bent-core compounds by incorporating emissive properties to such systems while retaining their liquid crystalline properties.

Mr. Deb enjoys designing and constructing molecular self-assemblies with tailor-made properties. His current research interests encompass different branches of soft condensed matter and optical physics, including novel laser trapping and fluorescence confocal imaging techniques. Apart from designing and synthesis of functionalized molecular electronic materials which he is presently perusing.

The picture shows the B7 phase texture formed by the emissive liquid crystal belonging to only one family of four rings bent core mesogens. On cooling from the isotropic phase, the B7 phase nucleates as spiral domains. The image revealed the coexistence of different type of long spiral colourful helical ribbons (beaded-, screw-like). A super coil is formed after two parts of the filaments cross each other. On further cooling these spiral domains coalesce to form very complicated and extraordinary textures (one could note that pendent like domain). These textural variants frequently occur at different places within the same sample preparation. Some of these ribbons show the remarkable constancy of the pitch all along the length. Stability of these spiral features depends on the thickness of the sample, thicker sample shows bending and bifurcating instabilities, for taking this image 5μm cell was used. The picture was taken on a Nikon LV100 POL polarizing optical microscope with Olympus C5050 digital camera.

Jury comment: This picture was chosen as it is an elegant and beautiful example of the texture of the B7 phase.