Equilibrium properties of a grafted polyelectrolyte with explicit counterions

Abstract

We study the equilibrium conformations of a grafted polyelectrolyte (PE) in the presence of explicit counterions (CI) using Monte Carlo simulations. The interplay between attractive Lennard-Jones interactions (parametrized by epsilon), and electrostatics (parametrized by A = q^2l_B/a, where q =counterion valency, l_B = Bjerrum length and a = 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 -> . . . -> S -> G with increasing A, i.e., a change from poor to good, to reentrant poor solvent, whereas, at lower epsilon, the sequence of transitions is, E -> S -> G. The conformation changes are directly related to the nature of binding of CI onto the PE. The transition between S -> G is continuous and associated with critical fluctuations in the shape driven by fluctuations in the fraction of condensed CI.

Latex file and 9 eps figures are in .tar.gz file Submitted to Journal of Chemical Physics

References in corpus (5)

• The fraction of condensed counterions around a charged rod: Comparison of Poisson-Boltzmann theory and computer simulations
• Instabilities of Charged Polyampholytes
• Chain Collapse and Counterion Condensation in Dilute Polyelectrolyte Solutions
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Cited by in corpus (4)

• Aggregation of rod-like polyelectrolyte chains in the presence of monovalent counterions
• Phase transitions of a single polyelectrolyte in a poor solvent with explicit counterions
• Weak polyelectrolytes in the presence of counterion condensation with ions of variable size and polarizability
• Ensemble Equivalence for Counterion Condensation on a Two Dimensional Charged Disc