Self-Assembly of Mixed Amphiphile Systems Using the i-SAFT Density Functional Theory

The effects of amphiphiles (surfactants) on the thermophysical properties of interfaces between chemically dissimilar species (e.g., oil and water) are largely governed by the chemical structure of the amphiphiles and physical conditions of the system such as the pressure, temperature, and bulk solubility of the amphiphile. These conditions affect the equilibrium microstructure which in turn defines the interfacial tension. This work justifies the interfacial statistical associating fluid theory (i-SAFT) density functional theory (DFT) approach against molecular simulation data for a model oil-water-surfactant system. Then, a more extensive systematic study is carried out to analyze the effect amphiphile structure and concentration have on the equilibrium microstructure and interfacial tension.