Liquid-liquid interfacial tension of electrolyte solutions
Liquid-liquid interfacial tension of electrolyte solutions
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DOI：
10.1103/physrevlett.101.046104
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发表时间：
2008-07-25
影响因子：
8.6
通讯作者：
van Roij, Rene
中科院分区：
文献类型：
--
作者：
Bier, Markus;Zwanikken, Jos;van Roij, Rene
理论上证明了两种电解质溶液之间的超额液-液界面张力与离子强度I的函数关系，对于小的I，表现为O(-根I)，对于大的I，表现为O(+/-I)。由于离子在两种液体之间的不均匀分配，前者由静电势所支配，而后者与有限的界面厚度有关。这两个渐近区域之间的交叉敏感地依赖于材料参数，这表明实验上可获得的离子强度范围可以对应于小的或大的离子强度区域。在没有离子分配的气液界面的极限情况下，离子强度I较小时，镜像电荷相互作用可以控制表面张力，从而可以得到Onsager-Samaras极限定律O(-I ln(I))。
It is theoretically shown that the excess liquid-liquid interfacial tension between two electrolyte solutions as a function of the ionic strength I behaves asymptotically as O(-root I) for small I and as O(+/- I) for large I. The former regime is dominated by the electrostatic potential due to an unequal partitioning of ions between the two liquids whereas the latter regime is related to a finite interfacial thickness. The crossover between the two asymptotic regimes depends sensitively on material parameters suggesting that the experimentally accessible range of ionic strengths can correspond to either the small or the large ionic strength regime. In the limiting case of a liquid-gas surface where ion partitioning is absent, the image charge interaction can dominate the surface tension for small ionic strength I such that an Onsager-Samaras limiting law O(- I ln(I)) is expected.