Van der Waals-Like Isotherms in a Confined Electrolyte by Spherical and Cylindrical Nanopores

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• 作者：Gabriel E. Aguilar-Pineda ; Felipe Jim&eacute ; nez-Á ; ngeles ; Jiang Yu ; Marcelo Lozada-Cassou
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：March 1, 2007
• 年：2007
• 卷：111
• 期：8
• 页码：2033 - 2044
• 全文大小：214K
• 年卷期：v.111,no.8(March 1, 2007)
• ISSN：1520-5207

文摘

Electrolytes confined by spherical, cylindrical, and slit-like charged nanopores are studied. Results for ionicdistribution profiles, pressures of the confined fluid, and absorption isotherms are obtained through thehypernetted chain/mean spherical approximation (HNC/MSA) integral equations theory. In spherical andcylindrical geometries, an inward, non-monotonic behavior of the pressure is found as confinement increases,implying a negative compressibility. The pressure vs volume isotherms resemble liquid-vapor van der Waals-like phase transition diagrams. This effect is correlated with a charge separation inside a spherical porepreviously reported (Phys. Rev. Lett., 79, 3656, 1997). Here, the mechanism of charge separation and negativecompressibility are explored in detail. When compared with the slit-like pore pressure, important qualitativedifferences are found.