Molecular dynamics simulation of dual amino-functionalized imidazolium-based ionic liquids

In this work, the all-atom (AA) force fields were set up for three kinds of dual amino-functionalized imidazolium-based ionic liquids (ILs), composed by cations with different alkyl chain length and amino acid anion [Gly]−. The force field was based on our previous work and the default parameters were developed in this study. Molecular dynamics simulations were performed. Validation was carried out by comparing simulation densities with experimental data, and good agreement was obtained. Molar volume and heat capacity at constant pressure were predicted. Mean square displacements for these ILs were computed and these ILs were proved to move very slowly. It may be caused by hydrogen-bonded network between ions and the terminal azyl. To depict the microscopic structures of the ILs, many types of radial distribution functions were investigated. It is interesting to find that not only the cation and anion, but also the anions themselves will form hydrogen bonds.