Systematics of wetting and layering phenomena in smectic materials

A lattice model is used to investigate the surface behavior of smectic fluids close to the onset of smectic ordering. At the smectic-isotropic interface the nematic features of the smectic phase persist further into the bulk isotropic phase than the strictly smectic features. At the isotropic-vapor interface we find the possibility of a series of first-order layering transitions, each involving the addition of a smectic layer, in line with recent experimental results. However, at the nematic-vapor interface surface smectic order, if it exists, grows smoothly without layering transitions.