This thesis explores the dispersion stability, microstructure and phase transitions involved in the nanoclay system. It describes the recently discovered formation of colloidal gels via two routes: the first is through phase separation and second is by equilibrium gelation and includes the first reported experimental observation of a system with high aspect ratio nanodiscs. The phase behavior of anisotropic nanodiscs of different aspect ratio in their individual and mixed states in aqueous and hydrophobic media is investigated. Distinct phase separation, equilibrium fluid and equilibrium gel phases are observed in nanoclay dispersions with extensive aging. The work then explores solution behavior, gelation kinetics, aging dynamics and temperature-induced ordering in the individual and mixed states of these discotic colloids. Anisotropic ordering dynamics induced by a water-air interface, waiting time and temperature in these dispersions were studied in great detail along with aggregation behavior of nanoplatelets in hydrophobic environment of alcohol solutions.
This thesis explores the dispersion stability, microstructure and phase transitions involved in the nanoclay system. It describes the recently discovered formation of colloidal gels via two routes: the first is through phase separation and second is by equilibrium gelation and includes the first reported experimental observation of a system with high aspect ratio nanodiscs. The phase behavior of anisotropic nanodiscs of different aspect ratio in their individual and mixed states in aqueous and hydrophobic media is investigated. Distinct phase separation, equilibrium fluid and equilibrium gel phases are observed in nanoclay dispersions with extensive aging. The work then explores solution behavior, gelation kinetics, aging dynamics and temperature-induced ordering in the individual and mixed states of these discotic colloids. Anisotropic ordering dynamics induced by a water-air interface, waiting time and temperature in these dispersions were studied in great detail along with aggregation behavior of nanoplatelets in hydrophobic environment of alcohol solutions.
Nominated as an outstanding Ph.D. thesis by Jawaharlal Nehru University, New Delhi, India A comprehensive exploration of the physical phenomena in nano clay systems Looks at the equilibrium gels, isotropic-anisotropic transition, aging phenomenon First study of the behavior of mixed nano clay dispersions Includes supplementary material: sn.pub/extras
Ravi Kumar Pujala
Aging Dynamics in Anisotropic Colloidal Dispersions Anitropic Ordering of Anisotropic Colloids Equilibrium Gels Ergodic to Nonergodic Transition Gels Formed Through Phase Sepration Isotropic-anisotropic Phase Transition Mixed Nanoclay Gels and Glasses Nanoclay Aggregation in Hydrophobic Media Nanoclay Dispersions Ordering Induced by Water-air interface