Anion‐based regulating mechanism of structural and diffusive property of ionic liquids

Abstract

Understanding the regulating mechanism of diffusive properties of ionic liquids (ILs) is vital for their practical chemical engineering applications. Herein, we investigate the regulating mechanism of three properties, the structural, thermodynamical, and diffusive properties, of imidazole ILs with 18 kinds of anion via molecular dynamics simulations combined with theoretical analysis. It shows that the radial distribution function and coordinate number for these 18 ILs are similar to each other. However, the vibrational spectrum and diffusive property change greatly with the anion structure, in which the self‐diffusive coefficient (SDC) even changes by an order of magnitude. Furthermore, free energy and entropy have an exponential relationship with SDC, while other structural properties or cation–anion correlations cannot be directly related to SDC. These quantitative relationships suggest that entropy or free energy can serve as the key indicators in designing functional ILs for high‐performance applications in the chemical engineering field.