Modelling shear thinning of Imidazolium-based ionic liquids

We investigated rheological properties of 1-ethyl-3-methylimidazolium tetrafluoroborate as neat ionic liquid. We computed the shear viscosity at various shear rates using non-equilibrium molecular dynamics and observed a plateau regime prior to a decrease related to shear thinning. We employed a 1-dimensional diffusive model based on the Eyring one to investigate underlying molecular mechanisms. Shear thinning results from an apparent decrease of energy barriers encountered by ions when migrating from one metastable state to another one in a shear flow. Electrostatic interactions contribute to similar to 55% of those energy barriers. This method and findings set the basis for considering more complex ionic liquids.