For both solvents, the bulk density in the centre of the film was in good agreement with experimental values. We obtained approximately 742±5 g/L for n-hexadecane and 778±20 g/L for PAO4, which is below the experimental values by 2 % and 4 %, respectively. At the end of the equilibration phase, the separation between the two walls was 12 nm for nhexadecane and 11 nm for PAO4. The interaction of the hematite surface with the base oil gave in both cases rise to a layering of the solvent molecules, as can be seen from the mass density profiles of the solvent molecules after equilibration in Fig. . The layering next to the wall is stronger for linear n-hexadecane than branched PAO4, in agreement with previous MD simulations. The layers are slightly thicker for PAO4 than n-hexadecane.