Bending stiff charged polymers: the electrostatic persistence length
Abstract
Many charged polymers, including nucleic acids, are locally stiff. Their bending rigidity -- quantified by the persistence length --, depends crucially on Coulombic features, such as the ionic strength of the solution which offers a convenient experimental route for tuning the rigidity. While the classic Odijk-Skolnick-Fixman treatment fails for realistic parameter values, we derive a simple analytical formula for the electrostatic persistence length. It is shown to be in remarkable agreement with numerically obtained Poisson-Boltzmann theory results, thereby fully accounting for non-linearities, among which counter-ion condensation effects. Specified to double-stranded DNA, our work reveals that the widely used bare persistence length of 500\,\AA\ is overestimated by some 20%
Keywords
Cite
@article{arxiv.1611.00520,
title = {Bending stiff charged polymers: the electrostatic persistence length},
author = {E. Trizac and T. Shen},
journal= {arXiv preprint arXiv:1611.00520},
year = {2016}
}