Assessing the reliability of computing ion pair lifetimes and self-diffusivity to predict experimental viscosity trends of ionic liquids

Abstract

Self-diffusivities and ion pair lifetimes were calculated for 24 ionic liquids at 400 K. These values were then compared with the experimental viscosities of the ionic liquid at 298 K. Experimental viscosities were found to have a strong correlation with both the ion pair lifetime and the inverse diffusivity. For both properties, the ionic liquids were divided into two groups based on the nature of the anion. It was found that both the ion pair lifetime and the self-diffusivity can be used to predict the ionic liquids with a viscosity lower than a given threshold with an 80% success rate. This predictive capability would allow for rapid screening of ionic liquids to determine those with low viscosities.