大离子从电解质溶液吸附：修正泊松-玻尔兹曼方程
摘要
我们理论地研究了靠近带电表面的电解质溶液行为。 presented a modified Poisson-Boltzmann equation which takes into account the volume excluded by the ions in addition to the electrostatic interactions. In a formal lattice gas formalism the modified Poisson-Boltzmann equation can be obtained from a mean-field approximation of the partition function. In an alternative phenomenological approach, the same equation can be derived by including the entropy of the solvent molecules in the free energy. In order to visualize the effect of the steric repulsion, a simple case of a single, highly charged, flat surface is discussed. This situation resembles recent adsorption experiments of large ions onto a charged monolayer. A simple criterion for the importance of the steric effects is expressed in terms of the surface charge density and the size of the ions. It is shown that when these effects are important a saturated layer is formed near the surface. A modified Grahame equation relating the ion concentration at the surface to the surface charge density is obtained.
引用
@article{arxiv.cond-mat/9911482,
title = {Adsorption of Large Ions from an Electrolyte Solution: A Modified Poisson-Boltzmann Equation},
author = {I. Borukhov and D. Andelman and H. Orland},
journal= {arXiv preprint arXiv:cond-mat/9911482},
year = {2007}
}
备注
18 pages, 7 postscript figures included. Submitted to Electrochimica Acta