Ion specificity and anomalous electrokinetic effects in hydrophobic nanochannels
Abstract
We demonstrate with computer simulations that anomalous electrokinetic effects, such as ion specificity and non-zero zeta potentials for uncharged surfaces, are generic features of electro-osmotic flow in hydrophobic channels. This behavior is due to the stronger attraction of larger ions to the ``vapour--liquid-like'' interface induced by a hydrophobic surface. An analytical model involving a modified Poisson--Boltzmann description for the ion density distributions is proposed, which allows the anomalous flow profiles to be predicted quantitatively. This description incorporates as a crucial component an ion-size-dependent hydrophobic solvation energy. These results provide an effective framework for predicting specific ion effects, with important implications for the modeling of biological problems.
Keywords
Cite
@article{arxiv.cond-mat/0701072,
title = {Ion specificity and anomalous electrokinetic effects in hydrophobic nanochannels},
author = {David M. Huang and Cecile Cottin-Bizonne and Christophe Ybert and Lyderic Bocquet},
journal= {arXiv preprint arXiv:cond-mat/0701072},
year = {2009}
}