论文标题
溶剂的不对称耗竭对二元极性溶剂混合物中带电对象的电动双层的影响
Influence of asymmetric depletion of solvents on the electric double layer of charged objects in binary polar solvent mixture
论文作者
论文摘要
对于由离子和两种极性溶剂组成的二进制溶剂混合物，带电物体附近的电动双层不仅受到二元溶剂组成的强烈影响，而且还受到溶剂分子的体积和偶极矩的性质。考虑到溶剂尺寸的差异和溶剂偶极子的定向排序，我们从理论上获得了溶剂和离子的空间分布函数，平面几何形状和平均场方法中的一般表达式。尽管着重于远程静电相互作用，但我们忽略了诸如优先溶剂化等短距离相互作用，我们的方法预测了两种溶剂的不对称耗尽，而二进制溶剂混合物的介电率降低了。此外，我们建议耗竭的关键因素是溶剂偶极矩与溶剂体积的比率。分别提出和讨论了二元溶剂组成，溶剂的体积和溶剂偶极力矩对溶剂的数量密度，介电常数和差异电容的影响。我们得出的结论是，要考虑新方法的差异，以代表更现实的情况，例如优先溶剂，因此需要考虑到极性溶剂之间的差异。
For binary solvent mixtures composed of ions and two kinds of polar solvents, electric double layer near a charged object is strongly affected by not only the binary solvent composition but also nature of solvents such as volume and dipole moment of a solvent molecule. Accounting for difference in sizes of solvents and orientational ordering of solvent dipoles, we theoretically obtain general expressions for the spatial distribution functions of solvents and ions, in planar geometry and within the mean-field approach. Although focusing on long-range electrostatic interaction, we neglect short-range interactions such as preferential solvation, our approach predicts an asymmetric depletion of the two solvents from the charged surface and a behavior of decreased permittivity of the binary solvent mixture. Furthermore, we suggest that the key factor for the depletion is the ratio of the solvent dipole moment to the solvent volume. The influence of binary solvent composition, volume of solvent and dipole moment of solvent on the number density of solvents, permittivity and differential capacitance are presented and discussed, respectively. We conclude that accounting for difference in the volume and dipole moment between polar solvents is necessary for new approach to represent more realistic situations such as preferential solvation.
