Competitive Interactions at Electrolyte/Octanol Interfaces: A Molecular Perspective

Much is understood about electrolyte liquid/liquid interfaces, yet the relationships between ion solvation, adsorption, and the instantaneous surface have not been the topic of significant study. The thermally corrugated capillary wave characteristics of the instantaneous aqueous surface contribute to the heterogeneous interfacial structural and dynamic properties. These properties are sensitive to the nature of the immiscible nonpolar solvent. In this work, we examine the role of interfacial heterogeneity upon ion behavior and further how this is influenced by a partially polar solvent relative to a vapor-phase analogue. We compare and contrast ion solvation in electrolyte/vapor and electrolyte/octanol biphasic systems, focusing upon the changes to interfacial heterogeneity in the presence of the octanol solvent and the variations of ion concentration at different interfacial regions. The interplay between competing forces introduced by strong octanol-water interactions at the interface is examined, with a new understanding of how such a competition may lead to tailored interfacial properties.