Molecular Dynamics Simulation of the 1-Butyl-3-methylimidazolium Nitrate Ionic Liquid and the Dynamical Behavior of the Ionic Liquid-Water Binary Mixtures

For long last time water has been considered as an inimical contaminant to pure Ionic Liquids (ILs) because the presence of a low amount of water drastically changes the properties of ILs. But, water is now a very important partner for ILs because mixing the IL-water is an easy strategy to control and access to unique properties of both of them. Applying this type of binary mixtures also provides a broad application in different fields. In this work, molecular dynamics simulations were used to study the details of the dynamical behavior of the binary mixture of 1-butyl-3-methylimidazolium nitrate ([bmim][NO3]) and water in different molar fractions in order to discover the influence of water addition on the properties of the ionic liquid. The dynamics of systems studied by the computing of mean-square displacement and self-diffusion coefficients of species. The presence of water causes significant enhancement of ionic self-diffusion coefficients. In neat IL and the concentrated IL solution, self-diffusion of the cation is higher than that of the anion; however, in the binary mixtures with the water molar fraction greater than or equal to 0.25, the anions diffuse faster than the cations.