We consider a near-critical binary mixture with addition of antagonistic salt confined between weakly charged and selective surfaces. A mesoscopic functional for this system is developed from a microscopic description by a systematic coarse-graining procedure. The functional reduces to the Landau-Brazovskii functional for amphiphilic systems for sufficiently large ratio between the correlation length in the critical binary mixture and the screening length. Our theoretical result agrees with the experimental observation [Sadakane et.al. J. Chem. Phys. {\bf 139}, 234905 (2013)] that the antagonistic salt and surfactant both lead to a similar mesoscopic structure. For very small salt concentration $ρ_{ion}$ the Casimir potential is the same as in a presence of inorganic salt. For larger $ρ_{ion}$ the Casimir potential takes a minimum followed by a maximum for separations of order of tens of nanometers, and exhibits an oscillatory decay very close to the critical point. For separations of tens of nanometers the potential between surfaces with a linear size of hundreds of nanometers can be of order of $k_BT$. We have verified that in the experimentally studied samples [Sadakane et.al. J. Chem. Phys. {\bf 139}, 234905 (2013), Leys et.al. Soft Matter {\bf 9}, 9326 (2013)] the decay length is too small compared to the period of oscillations of the Casimir potential, but the oscillatory force could be observed closer to the critical point.
Effects of Divalent Cations on Diffusion Dynamics of Biological Water Confined between Lipid Membranes
Global Science Research Center for Systems Chemistry (GCSC)（系统化学全球研究中心）；Department of Chemistry, Chung-Ang University（中央大学化学系）；Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS)（基础科学研究院分子光谱与动力学中心）；Department of Chemistry, Korea University（韩国大学化学系）
Electrolytes in regimes of strong confinements: surface charge modulations, osmotic equilibrium and electroneutrality
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。
