Ion Distributions at the Nitrobenzene-Water Interface Electrified by a Common Ion
Abstract
Synchrotron x-ray reflectivity is used to study ion distributions at the liquid-liquid interface between a nitrobenzene solution of tetrabutylammonium tetraphenylborate (TBATPB) and a water solution of tetrabutylammonium bromide (TBABr). The concentration of TBABr is varied to alter the ion distribution. Our x-ray measurements are inconsistent with several commonly used theories of ion distributions, including Gouy-Chapman, modified Verwey-Niessen, and the MPB5 version of the Poisson-Boltzmann equation. These structural measurements are described well by ion distributions predicted by a version of the Poisson-Boltzmann equation that explicitly includes a free energy profile for ion transfer across the interface when this profile is described by a simple analytic form or by a potential of mean force from molecular dynamics simulations. These x-ray measurements from the liquid-liquid interface provide evidence for the importance of interfacial liquid structure in determining interfacial ion distributions.
Keywords
Cite
@article{arxiv.cond-mat/0604182,
title = {Ion Distributions at the Nitrobenzene-Water Interface Electrified by a Common Ion},
author = {Guangming Luo and Sarka Malkova and Jaesung Yoon and David G. Schultz and Binhua Lin and Mati Meron and Ilan Benjamin and Petr Vanysek and Mark L. Schlossman},
journal= {arXiv preprint arXiv:cond-mat/0604182},
year = {2007}
}
Comments
51 pages, 14 figures, to be published in Journal of Electroanalytical Chemistry