The surface characterization of a 2-(diethylamino) ethyl methacrylate-2-(dimethylamino) ethyl methacrylate diblock copolymer [DEA-DMA] was carried out using inverse gas chromatography (IGC). The adsorption thermodynamic parameters (the standard enthalpy (ΔHo), entropy (ΔSo), and free energy of adsorption (ΔGo)), the dispersive component of the surface energy (γs d), and the acid-base character of the surface of the block copolymer were estimated using the retention time of different nonpolar and polar probes at infinite dilution region. This block copolymer showed convenient values of dispersive surface energy as compared to conventional polymers. The specific free energy of adsorption (ΔGsp), the specific enthalpy of adsorption (ΔHsp), and the specific entropy of adsorption (ΔSsp) of polar probes on diblock copolymer were determined. The values of the ΔHsp were correlated with both the donor and the modified acceptor numbers of the probes to quantify the acidic KA and the basic KD parameters of the block copolymer surface. The values obtained for the KA and KD parameters indicated a basic character for the surface of the DEA-DMA diblock copolymer. Copyright © 2006 John Wiley & Sons, Ltd.