Charge reversal of surfaces in divalent electrolytes: the role of ionic dispersion interactions.
Charge reversal of surfaces in divalent electrolytes: the role of ionic dispersion interactions.
复制标题
DOI：
10.1021/la9041265
复制
发表时间：
2010-05
期刊：
影响因子：
--
通讯作者：
D. Parsons;B. Ninham
中科院分区：
文献类型：
--
作者：
D. Parsons;B. Ninham
使用一种包含非静电离子 - 表面色散相互作用的改进的泊松 - 玻尔兹曼方法计算了云母表面碱土金属硝酸盐的表面电势。采用新的从头算动态极化率来确定色散相互作用。提出了一种描述阳离子水合层的水合模型。与实验结果高度吻合，包括在高电解质浓度下的电荷反转，且无需位点结合模型。这表明特定的离子色散力为离子表面结合提供了机制。在极高浓度极限下发现了渐近表面电势。根据电荷反转的强度预测出了霍夫迈斯特序列，即Mg＞Ca＞Sr＞Ba。水合离子的离子 - 表面色散吸附能似乎可以解释当考虑表面水合层时，在云母表面之间实验观察到的明显的排斥性二次水合力。
Surface potentials of alkali earth nitrates at a mica surface are calculated using a modified Poisson-Boltzmann approach that includes nonelectrostatic ion-surface dispersion interactions. New ab initio dynamic polarizabilities are used to determine dispersion interactions. A hydration model describing the hydration shell of cations is presented. Excellent agreement with experiment is achieved, including charge reversal at high electrolyte concentration without the need for site binding models. This suggests that specific ionic dispersion forces provide the mechanism for ion surface binding. An asymptotic surface potential is found in the limit of very high concentration. A Hofmeister series is predicted according to the strength of charge reversal, with Mg > Ca > Sr > Ba. The ion-surface dispersion adsorption energies of hydrated ions appear to explain the apparent repulsive secondary hydration forces observed experimentally between mica surfaces when taken with a surface hydration layer.