Molecular modeling of ionic liquid tribology: Semi-empirical bonding and molecular structure

The interactions between selected ionic liquids and either an aluminum oxide or a silicon nitride surface are modeled in this report using semi-empirical methods. The ionic liquids include a series of seven cationic imidazolium derivatives with PF6− as the anion. The tribological properties of these ionic liquids and their interactions with aluminum and Al-steel alloys are modeled using a smooth aluminum oxygen surface. The ionic liquids are allowed to form a complex with this surface and the enthalpies of complex formation are seen to correlate with the tribological properties of the seven ionic liquids. The seven ionic liquids are also complexed with a hexagonal silicon nitride surface and their tribological properties are predicted on the basis of complex formation enthalpies.