Surface and interaction characteristics of styrene-4 vinyl pyridine (S-4VP) diblock copolymers have been investigated by the method of inverse gas chromatography. Both constituents of the diblock were found to be basic, the 4VP moiety being the stronger base. When adsorbed onto a standard chromatographic support (Chromosorb), a mildly acidic surface, the 4VP block is preferentially oriented to the substrate, leaving an air interphase which is enriched in polystyrene (PS). The surface enrichment by PS is furthered by the lower surface energy of the PS block. Thus, when adsorbed on acidic surfaces, the wettability and related surface properties of P(S-4VP) diblocks will resemble those of PS, in keeping with the observed compositional heterogeneities.