Experimental and theoretical studies have been undertaken at RRI to deal with the structure property relations of ‘soft’ materials, which are easily deformable by external stresses, electric, and magnetic fields. Among these soft materials, thermotropic liquid crystals consisting of highly anistropic organic molecules, nano-composite materials, polymers and biomaterials such as biomolecules and cells are studied using a variety of experimental techniques. The interplay between the different degrees of freedom and various constraints present in these systems often give rise to rich and complex behaviour that can be exploited for potential technological applications.
The chemistry wing of the Soft Condensed Matter Group is involved in the design, synthesis and characterisation of novel liquid crystalline materials that exhibit remarkable electronic and optoelectronic properties. A number of monomeric, oligomeric, polymeric, and ionic liquid crystalline materials have been synthesized. The synthesis of liquid crystalline materials using microwave heating has also been carried out with a view to find quick and environment-friendly synthetic routes.
The incorporation of nanomaterials like metal-nanoparticles, quantum dots, carbon nanotubes and graphene in the supramolecular order of liquid crystals is likely to lead to novel materials for many applications. With this view, a research program has been initiated to prepare and functionalise these nanomaterials with discotic as well as other molecules and disperse them in monomeric, oligomeric and polymeric discotic liquid crystals. The dispersion of such functionalised nanomaterials in columnar matrix has been found to enhance physical properties such as conductivity and photoconductivity significantly.
One of the present research interests of the SCM group is in investigating electric field induced chiral symmetry breaking in liquid crystals made of achiral molecules. The structure and properties of novel field induced dark mesophases composed of electro optically switchable macroscopic chiral domains are being studied, using a variety of techniques like optical microscopy, dielectric spectroscopy and x-ray diffraction. Field dependent shape transitions, exhibited by the nucleating chiral domains, which form these mesophases, are also being studied in order to understand the observed enantioselectivity. The role of growth morphology in coarsening is under study to get a physical insight into the effects of chiral and electrostatic interactions. Studies of chiral thin films possessing tunable enantioselectivity are also interesting from a technological point of view, as they have potential for chiroptical and NLO applications.
Another area of interest is in understanding structure and dynamics of polyelectrolytes using dielectric spectroscopy. Very low frequency relaxation modes arising from polarization mechanisms involving counter ions and polar side chains are usually quite challenging to probe experimentally, and have therefore not been explored extensively. Detailed dielectric studies have been undertaken on some aqueous polyelectrolytes, some of which also exhibit coacervation.