Morphological phase transitions of thin fluid films on chemically structured substrates

Using an interface displacement model derived from a microscopic density functional theory we investigate thin liquid-like 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.