(413h) Enhancement of Polymer Globule Formation by Shear Flow

Polyelectrolytes, polymers in poor solvents, and other systems with attractions and repulsions show formation of globules/structures in equilibrium. Typically these transitions are driven by changes in temperature, salt concentration, pH, etc. In some systems, shear flow can act to accelerate or cause collapse, instead of the common case of shear acting to stretch the polymer. Since all atom simulations of such systems are computationally expensive, we have developed a new coarse-grained model. Brownian Dynamics simulations of this model with short ranged attractions and repulsions have been used to examine the long-time dynamics in shear flow and globule formation. We analyze the effect of shear flow on such systems as a barrier hopping process in a free energy landscape. For small shear rates, the flow acts to alter the first passage process across the barrier. At higher shear rates, the flow causes a hopping back and forth between the two states.