Dynamics of Collapse of Flexible Polyelectrolytes in Poor Solvents

Abstract

The collapse kinetics of strongly charged polyelectrolytes in poor solvents is investigated by Langevin simulations and scaling arguments. We investigate the role of valence z of counterions, solvent quality, and shape of counterions on the dynamics of collapse. On the basis of the simulations, a number of results are obtained. (1) The rate of collapse, which is measured using the time dependence of the radius of gyration of the chain, increases sharply as z increases from 1 to 4. The collapse is particularly slow for the monovalent case and is observed only when the solvent quality is sufficiently poor. (2) Although the routes to collapse depend on z and the solvent quality a general collapse mechanism emerges. Upon quenching to low temperatures, counterions condense rapidly on a diffusion-limited time scale. At intermediate times metastable pearl-necklace structures form. The clusters merge at longer times with the largest one growing at the expense of smaller ones which is reminiscent of the Lifshitz−S...