The Electrostatic Persistence Length of Polymers beyond the OSF Limit

Abstract

We use large scale Monte Carlo simulations to test scaling theories for the electrostatic persistence length $l_e$ of isolated, uniformly charged polymers with Ðintrachain interactions in the limit where the screening length $κ^{-1}$ exceeds the intrinsic persistence length of the chains. Our simulations cover a significantly larger part of the parameter space than previous studies. We observe no significant deviations from the prediction $l_e\proptoκ^{-2}$ by Khokhlov and Khachaturian which is based on applying the Odijk-Skolnick-Fixman theory to the stretched de Gennes-Pincus-Velasco-Brochard polyelectrolyte blob chain. A linear or sublinear dependence of the persistence length on the screening length can be ruled out. We argue that previous numerical results pointing into this direction are probably due to a combination of excluded volume and finite chain length effects. The paper emphasizes the role of scaling arguments in the development of useful representations for experimental and simulation data.

11 pages, 7 figures