Microscopic Structure, Thermodynamic and Transport Properties of Ionic Liquids: Molecular Simulations and Theoretical Predictions

An atomistic force field developed recently for imidazolium-based [Tf2N] ionic liquids (ILs) based on the combination of density functional theory quantum calculations and the CHARMM force field is used in this work for the determination of microscopic structure, thermodynamic properties and transport properties of IL melts over a wide temperature and pressure range. Molecular Dynamics simulations are performed and results are analyzed for the determination of microscopic phenomena and macroscopic physical properties. A broad range of properties that includes atom pair and center of mass radial distribution functions, mass densities, segmental and chain dynamics, and self-diffusion coefficient are calculated. Comparison against limited literature experimental data reveals that the new force field provides reliable predictions of a broad spectrum of properties. Furthermore, it is shown to be more accurate than earlier atomistic force fields.

Furthermore, calculations from the Perturbed Chain-Polar Statistical Associating Fluid Theory (PC-PSAFT) are presented regarding the phase equilibria of IL – solvent mixtures. Both non-polar and polar solvents are examined. PC-PSAFT provides an accurate correlation of binary and ternary mixture phase equilibria using a single binary interaction parameter.