Hard-sphere fluids in annular wedges: density distributions and depletion potentials.
Hard-sphere fluids in annular wedges: density distributions and depletion potentials.
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环形楔中的硬球流体：密度分布和耗尽电位。
DOI：
10.1103/physreve.79.061402
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
M. Oettel
中科院分区：
文献类型：
--
作者：
V. Boţan;F. Pesth;T. Schilling;M. Oettel
利用基本测度密度泛函理论、各向异性积分方程和数值模拟方法，研究了两个大溶质球或一个大溶质球与近壁形成的环形狭缝中溶剂硬球的密度分布和吸附.我们发现，在狭缝中的密度分布的主要特点是由一个有效的二维系统的磁盘在附近的一个中心障碍。这对溶质（或壁和溶质）之间的耗尽力具有直接的后果，因为后者由于在中心障碍物的圆周处的有效盘的吸附而接收到强的线张力贡献。对于大的溶质-溶剂尺寸比，由此产生的耗尽力有一个简单的几何解释，给出了一个精确的“胶体”限制耗尽相互作用。对于5-10的中间尺寸比和大于0.4的高溶剂填充分数，显式密度泛函结果显示在溶质接触处的耗尽势的深吸引力井，这可能表明在低溶质和高溶剂填充分数下的二元混合物中的分层除了发生凝胶化和冻结之外。
We analyze the density distribution and the adsorption of solvent hard spheres in an annular slit formed by two large solute spheres or a large solute and a wall at close distances by means of fundamental measure density-functional theory, anisotropic integral equations, and simulations. We find that the main features of the density distribution in the slit are described by an effective two-dimensional system of disks in the vicinity of a central obstacle. This has an immediate consequence for the depletion force between the solutes (or the wall and the solute) since the latter receives a strong line-tension contribution due to the adsorption of the effective disks at the circumference of the central obstacle. For large solute-solvent size ratios, the resulting depletion force has a straightforward geometrical interpretation which gives a precise "colloidal" limit for the depletion interaction. For intermediate size ratios of 5-10 and high solvent packing fractions larger than 0.4, the explicit density-functional results show a deep attractive well for the depletion potential at solute contact, possibly indicating demixing in a binary mixture at low solute and high solvent packing fraction besides the occurrence of gelation and freezing.