Recent experiments measuring the electrical conductivity of DNA molecules highlight the need for a theoretical model of ion transport along a charged surface. Here we present a simple theory based on the idea of unbinding of ion pairs. The strong humidity dependence of conductivity is explained by the decrease in the electrostatic self-energy of a separated pair when a layer of water (with high dielectric constant) is adsorbed to the surface. We compare our prediction for conductivity to experiment, and discuss the limits of its applicability.
@article{arxiv.0907.3124,
title = {Ionic conductivity on a wetting surface},
author = {Brian Skinner and M. S. Loth and B. I. Shklovskii},
journal= {arXiv preprint arXiv:0907.3124},
year = {2009}
}
Comments
5 pages, 3 figures; one section and two illustrations added; figures updated and discussion added; typo fixed