Bulk and interfacial thermodynamics and dynamics of ionic liquids-oil mixtures: A molecular dynamics simulation study

Ionic liquids (ILs) are molten salts that are known for their low vapor pressure, thermal stability, low toxicity, and promising rheological behavior that make ILs great candidates for high-performance, sustainable lubricants. In this work, all-atom MD simulations will be used to predict morphology, rheology, and interfacial thermodynamics of imidazolium-based ILs in oil. In the first step, we will present the effect of IL content and the molecular structure of ILs in hexadecane on the density, structure, and dynamics of the mixture at different temperatures in bulk. The impact of IL content, molecular structure, and temperature on the nanostructure of the mixture will be determined by performing clustering analysis of ions that directly affect the dynamics and rheology of these mixtures. The influence of the formation of ionic structures in oil on the dynamics, shear, and extensional rheology of IL-oil in bulk will be investigated. In the next step, the interfacial and microstructure of IL-oil mixtures comprised of different IL contents and molecular structures near solid surfaces will be considered, and the free energy of adsorption will be determined. The results presented in this work will guide the experimental design of IL additive for tribological applications.