The configurational dynamics of a polyelectrolyte (PE), subjected to a simple shear flow, is studied using Brownian dynamics (BD) and Dissipative Particle Dynamics (DPD) simulations of a bead-spring model with explicit counterions. We explore the effect of counterion condensation on the tumbling and extension of PEs by varying the shear rates for a range of values of the electrostatic coupling parameter A (which is defined as the ratio of the Bjerrum length to the size of the monomer). In all cases, the power spectrum of Rs(t) (which characterizes the projected length of the PE in the flow direction as a function of time) exhibits a power law decay at high frequencies, similar to that for a dumbbell in shear flow.
View Article and Find Full Text PDFWe study the equilibrium conformations of a grafted polyelectrolyte (PE) in the presence of explicit counterions (CIs) using Monte Carlo simulations. The interplay between attractive Lennard-Jones interactions (parametrized by epsilon) and electrostatics (parametrized by A=q(2)l(B)/a, where q is the CI valency, l(B) is the Bjerrum length, and a is the monomer diameter) results in a variety of conformations, characterized as extended (E), pearls with m beads (P(m)), sausage (S), and globular (G). For large epsilon, we observe a transition from G-->P(2)-->P(3)--> .
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