Chemistry

B. V. N. Phani Kumar
NMR Laboratory, Inorganic & Physical Chemistry Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI), Chennai

Abstract Soft materials, in particular, lyotropic and thermotropic liquid crystals, are the two interesting cases, where rich polymorphism of these systems is mainly induced by concentration and temperature, respectively. The atomistic level insights on self-aggregation and microstructure of associative copolymers exhibiting lyotropic liquid crystalline nature and their behavior in the presence of additives, are valuable in the formulation of new products. NMR techniques such as spin-relaxation and self-diffusion have been emerged as powerful probes to monitor the local and global dynamics of soft materials, and hence rich description of molecular dynamics and its correlation with microstructure. Furthermore, saturation transfer difference (STD) NMR combined with selective relaxation methods points out the spatial proximities of ligands with biological macromolecules as well as fruitful information on binding affinity. In thermotropic liquid crystals, the molecular motions those are important from NMR relaxation point of view are ultra-slow (collective) motions and fast (non-collective) motions. Variable-frequency spin-relaxation rates (Fast Field Cycling NMR Dispersion) with a suitable analysis permits to decouple above mentioned motions and throw light on orientation order, which is quite interesting in the context of thermotropic liquid crystals. Hence, the present talk is focused on the application of NMR to such soft systems.