arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2009.07324cond-mat.soft
收藏

强约束条件下的电解质:表面电荷调制、渗透平衡和电中性

Electrolytes in regimes of strong confinements: surface charge modulations, osmotic equilibrium and electroneutrality

Amin Bakhshandeh, Maximiliano Segala, Thiago Colla

摘要:

在目前的工作中,我们研究的电解质溶液之间的平面表面与nonopatterned带电域,已连接到一个散装离子水库。该系统是通过改进的蒙特卡罗(MC)模拟方法,适用于模拟的电解质调制的表面电荷分布的存在下进行调查。我们还采用了线性方法的精神,经典的德拜-休克尔近似,它允许一个获得明确的表达式的平均电位,离子配置文件,有效的表面相互作用和净离子电荷之间的墙壁。重点放在强约束电解质的限制,在这种情况下,在表面间空间的局部电中性可能不会得到满足。为了评估这种局部电荷中性的缺乏对具有调制电荷域的表面之间的离子诱导相互作用的影响,我们考虑了受限电解质的两个不同的模型系统:其中明确考虑盐储库{ \it via}与固定体积浓度的电解质的渗透平衡,第二种是隐含地考虑了与电荷中性离子库的平衡。虽然在前一种情况下,渗透离子交换可能会导致非零净电荷,在后一种模式中,通过在带电界面上出现隐含的唐南电位来强制执行电荷中性。在所有的粒子分离的离子诱导的表面相互作用在所采用的模型系统中观察到一个很强的依赖性。这些研究结果强烈表明,在选择不同的方案来描述带电表面之间的电解质中的离子交换时,即使在不存在非零净电荷(non-zero net charge)表面贡献的情况下,也要小心。

英文摘要:

In the present work, we study an electrolyte solution confined between planar surfaces with nonopatterned charged domains, which has been connected to a bulk ionic reservoir. The system is investigated through an improved Monte Carlo (MC) simulation method, suitable for simulation of electrolytes in the presence of modulated surface charge distributions. We also employ a linear approach in the spirit of the classical Debye-Hückel approximation, which allows one to obtain explicit expressions for the averaged potentials, ionic profiles, effective surface interactions and the net ionic charge confined between the walls. Emphasis is placed in the limit of strongly confined electrolytes, in which case local electroneutrality in the inter-surface space might not be fulfilled. In order to access the effects of such lack of local charge neutrality on the ionic-induced interactions between surfaces with modulated charge domains, we consider two distinct model systems for the confined electrolyte: one in which a salt reservoir is explicitly taken into account {\it via} the osmotic equilibrium with an electrolyte of fixed bulk concentration, and a second one in which the equilibrium with a charge neutral ionic reservoir is implicitly considered. While in the former case the osmotic ionic exchange might lead to non-vanishing net charges, in the latter model charge neutrality is enforced through the appearance of an implicit Donnan potential across the charged interfaces. A strong dependence of the ionic-induced surface interactions in the employed model system is observed at all particle separations. These findings strongly suggest that due care is to be taken while choosing among different scenarios to describe the ionic exchanging in electrolytes confined between charged surfaces, even in cases when the monopole (non zero net charge) surface contributions are absent.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑