Vapor-liquid interfacial properties of ionic liquids

Ionic liquids are essentially molten salts composed entirely of a mixture of anions and cations with a melting temperature below the boiling temperature of water. These are rapidly gaining interest as replacements for traditional organic solvents used in chemical processes. They have the ability to dissolve an enormous range of inorganic, organic, and polymeric materials at very high concentrations, are noncorrosive, and have low viscosities and no significant vapor pressures. In this work, we developed a new version of SAFT EOS to describe the behavior of vapor-liquid interfacial properties of ionic liquids using a density functional theory (DFT). We have calculated the surface tension as well as interfacial surface thickness with use of three methods, including the common intersection method (CIM), Winkelmann method and inversion method. The calculated results are also compared with experimental data and show that these methods are given satisfactory predictions the surface thickness and its corresponding surface tension at various temperature.