Wax deposition onto Fe2O3 surfaces

Abstract

The deposition of wax onto hematite surfaces has been investigated using molecular dynamics simulations. This process has been modelled using n-octacosane (C₂₈) as a representative wax molecule and the (0001) and (102) 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 C₂₈ molecules about their long axis: the alkanes are tilted relative to the (0001) surface, but lie flat to the (102) surface. Radial distribution functions show that the structure of the surface deposit is comparable with the C₂₈ 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.