  Using an interface displacement model derived from a microscopic density
functional theory we investigate thin liquidlike wetting layers adsorbed on
flat substrates with an embedded chemical heterogeneity forming a stripe. For a
wide range of effective interface potentials we find first-order phase
transitions as well as continuous changes between lateral interfacial
configurations bound to and repelled from the stripe area. We determine phase
diagrams and discuss the conditions under which these morphological changes
arise.
