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arXiv 1507.04815cond-mat.softphysics.comp-ph
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从自洽场模型理解耗尽诱导类电荷吸引

Understanding depletion induced like-charge attraction from self-consistent field model

Pei Liu, Manman Ma, Zhenli Xu

摘要:

由于库仑相互作用,可能带电的粒子/表面之间的相互作用力通常是排斥的。然而,在实验中经常观察到电解质中违反直觉的类电荷吸引,这在理论上争论了很长时间。众所周知,平均场泊松-玻尔兹曼理论不能解释或预测这种反常特征,因为它忽略了多体性质。在本文中,我们开发了有效的算法,并进行两个界面之间的力的计算使用一组自洽方程,适当地考虑到静电相关和介电边界效应。通过求解方程组和计算Debye充电过程中的压强,我们发现自洽方程组可以用来研究从弱耦合到中等耦合的同电荷表面之间的吸引,这种吸引是由于静电驱动的熵力,而这种熵力由于可动离子的介电耗尽而显著增强。一个系统的研究表明,相互作用力可以调谐材料的介电常数,离子的大小和价态,和盐浓度,并只存在于这些参数的特定制度的类电荷吸引。

英文摘要:

The interaction force between likely charged particles/surfaces is usually repulsive due to the Coulomb interaction. However, the counterintuitive like-charge attraction in electrolytes has been frequently observed in experiments, which has been theoretically debated for a long time. It is widely known that the mean field Poisson-Boltzmann theory cannot explain or predict this anomalous feature since it ignores many-body properties. In this paper, we develop efficient algorithm and perform the force calculation between two interfaces using a set of self-consistent equations which properly takes into account the electrostatic correlation and the dielectric-boundary effects. By solving the equations and calculating the pressure with the Debye-charging process, we show that the self-consistent equations could be used to study the attraction between like-charge surfaces from weak-coupling to mediate-coupling regime, and that the attraction is due to the electrostatics-driven entropic force which is significantly enhanced by the dielectric depletion of mobile ions. A systematic investigation shows that the interaction forces can be tuned by material permittivity, ionic size and valence, and salt concentration, and that the like-charge attraction exists only for specific regime of these parameters.

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。

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