THEORETICAL FORMULATION OF DYNAMICS IN POLYMERIC LIQUIDS

Abstract

In this thesis, I discuss primarily the generalization of di using di usivity concept to many particle model system with localized interactions. The model system comprises a chain of connected beads, the Rouse model where Brownian motion of beads describe the polymer dynamics. Di using di usivity initially developed for single particle di usion, models the crowded environment in complex liquids where particle di usivity is stochastic in time. This thesis discusses one of a kind generalization of this single particle concept to Rouse model by considering di usion of independent Rouse modes in mode resolved crowded environment. Rouse mode di usion coe cients are modeled as independent multi-dimensional Ornstein- Uhlenbeck processes. An exact analytic treatment thus made possible leads to distributions of single mode displacements, chain averaged bead displacement, and their corresponding moments. The theoretical formulation is applied to polymer liquids, where anomalous center of mass and monomer dynamics can be explained with reasonable success, speci cally in simulation trajectories for unentangled polymer melts.