The base oil and OFM molecules were modeled using the all-atom long chain-optimised potential for liquid simulations (L-OPLS-AA) force field. This is an updated version of OPLS-AA 62 in which some of the parameters for C and H atoms are adjusted to accurately reproduce the experimental density and viscosity of long chain alkanes. Parameters for the other atoms remain unchanged from the orignal OPLS-AA forc field. The Lennard-Jones parameters and partial charges for the Fe and O atoms in the α-Fe 2 O 3 surface were taken from Berro et al. Moreover, harmonic bonds with a force constant of 130 kcal mol -1 Å -1 were added between atoms within 0.3 nm of each other in their lattice positions. Bond lengths were taken from X-ray diffraction experiments by Blake et al. This combination of force fields has already been successfully used by Ewen et al. in nonequilibrium molecular dynamics (NEMD) simulations of OFM friction.