Tribological properties of imidazolium based ionic liquids confined between two ordered self-assembled monolayers of alkylsilane chains on a silicon dioxide surface are studied using molecular dynamics simulations. Simulations are performed for odd and even alkylsilane chain lengths over a range of shear velocities and normal loads and are compared with experimental results using tribometry. Effects of lubricant layer thickness, as well as chemical composition of the ionic liquids and structural defects in the self-assembled monolayers are considered using both simulations and experiments. The experiments reveal that a critical surface energy is required for the ionic liquids to form a continuous film. This result is supported through simulations of ionic liquid contact angles on surfaces of different composition. Alignment of the ions at rest and under shear is also explored through both experiments and simulations.