Effect of Temperature on Surfactant Adsorption at the Liquid-Liquid Interface: Insights from Molecular Dynamics Simulations

Much is known about the effect of surfactants on the heterogeneity of liquid-liquid interfaces, but interfacial properties are sensitive to temperature. The relationship between temperature, surfactant adsorption, and interface structure has not yet been a major research topic. In this work, the effect of temperature on the interfacial structure of the tri-n-butyl phosphate saturated water/octane was investigated through molecular dynamics simulations. We compared the differences in interfacial tension curves of water/organic systems with and without surfactants at different temperatures, focusing on the effects of temperature on surfactant adsorption, interfacial stability, hydrogen bond network, and water extraction. We found the temperature dependence of interfacial protrusion formation and provided a molecular-level understanding of how protrusions promote subsequent water extraction processes.