Prof. Ravi Prakash Jagadeeshan's Talk

Dec 06, 2012 - 17:00

Dec 06, 2012 - 18:00

Room 118 (Creativity Hall) Ground Floor Chemical Engineering Department

Seminars

Prof. Ravi Prakash Jagadeeshan Department of Chemical Engineering Monash University

Abstract Many important phenomena in both industrial and biological contexts involve semidilute polymer solutions. However the behaviour of polymer solutions is presently well understood only in the dilute and concentrated solution limits. We report on investigations of the dynamics of semidilute solutions of DNA through experiments and computer simulations. The experiments probe the linear and non-linear vlsooelastlc benaviour In a wide range of molecular weights temperatures and concentrations. The dependence of the zero shear rate viscosity on concentration is observed to display universal behaviour that can be understood within the framework of the blob theory for semidilute polymer soludons. Further the shear rate dependence of viscosity at various temperatures and concentrations can be collapsed onto master curves when understood in terms of a relaxation time that depends on concentration. Computational prediction of the static and dynamic properties of semldllute polymer solutions requires the simulation of a large system of polymer chains interacting with each other through excluded volume and hydrodynamic Interactions. We describe the development of a Brownian dynamics simulation algorithm that uses a fast implementation of the Ewald summation method to obtain predictions of the concentration dependence of static propertIes such as the radius of gyration and of dynamic properties such as the long-time diffusivity and the viscosity. Predictions are compared with experimental observatlons on DNA solutions.