To predict the behaviour at both the solid and vapour interfaces, we have used the free energy described in eqn (3), with the entropic component determined from the bulk volume fraction and shape anisotropy of each system as described by eqns ( ) and ( ) for the solid and vapour interfaces, respectively, and with the energetic component determined from the nearest-neighbour in-teractions in the interfacial layer as described by eqn (7).