2008/05/14 by Akira Ōnuki, Akira Onuki · 1 citation
Chemical Engineering · Chemistry · Physics and Astronomy · #Chemical and Physical Properties in Aqueous Solutions #Electrostatics and Colloid Interactions #Spectroscopy and Quantum Chemical Studies #cond-mat.soft
paper · pdf · doi:10.1063/1.2936992
8 figures
arxiv created 2008/05/14 · openalex publication_date 2008/06/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We calculate the ion distributions around an interface in fluid mixtures of highly polar and less polar fluids (water and oil) for two and three ion species. We take into account the solvation and image interactions between ions and solvent. We show that hydrophilic and hydrophobic ions tend to undergo a microphase separation at an interface, giving rise to an enlarged electric double layer. We also derive a general expression for the surface tension of electrolyte systems, which contains a negative electrostatic contribution proportional to the square root of the bulk salt density. The amplitude of this square-root term is small for hydrophilic ion pairs but is much increased for hydrophilic and hydrophobic ion pairs. For three ion species, including hydrophilic and hydrophobic ions, we calculate the ion distributions to explain those obtained by x-ray reflectivity measurements.