(64g) Molecular Modeling Insights into the Mechanisms for Viscosity Trends in Ionic Liquids

Ionic liquids, defined as salts that in their pure state melting at a temperature below 100 ^oC, have come under intense study over the past decade due to their unique properties such as negligible vapor pressure, ionic conductivity and excellent solvation properties. One of the major drawbacks of ionic liquids, however, is that they tend to be more viscous than conventional organic solvents. In this work, we report the results of molecular dynamics simulations in which the viscosity of pure ionic liquids and those mixed with low viscosity diluents is computed. We show that the characteristic time associated with local ion exchange correlates well with the viscosity of the liquid. Using this concept, we propose several structural modifications that can be made which should lower the viscosity of ionic liquids.