Wax deposition onto Fe2O3 surfaces

The deposition of wax onto hematite surfaces has been investigated using molecular dynamics simulations. This process has been modelled using n-octacosane (C-28) as a representative wax molecule and the (0001) and (10(1) over bar 2) hematite surfaces, which are believed to be the predominant Fe2O3 surfaces. The adsorption sites and corresponding energies have been determined and indicate that deposition is more favourable on the ( 0001) surface. Different crystalline structures are yielded on each surface, differing mainly in a rotation of the C-28 molecules about their long axis: the alkanes are tilted relative to the (0001) surface, but lie at to the (10(1) over bar 2) surface. Radial distribution functions show that the structure of the surface deposit is comparable with the C-28 crystal only on the (0001) Fe2O3 surface. An energetic analysis of both systems also indicates that the deposition process is more favourable on the ( 0001) surface.