Interaction of fluids with physically patterned solid surfaces

We derive coarse-grained potentials for the interaction of a fluid atom with a solid substrate patterned with cylindrical or rectangular pillars, as well as with rectangular grooves. These potentials rely on the assumption of pairwise Lennard-Jones (LJ) (12-6) interactions of a fluid atom with a surface that has a uniform density of solid atoms. In the limit of a flat, semi-infinite surface, this potential becomes the LJ 9-3 potential. Simplified forms of the potentials are presented that are valid for sufficiently large pillars or grooves. The potentials can be truncated for greater computational efficiency while retaining similar accuracy to the full form. Both the full and simplified potentials exhibit the same features as a full summation of LJ (12-6) interactions, and these may be used in simulation studies to resolve phenomena associated with the interaction of fluids with patterned surfaces.