Chromatographic paper has long been used for electrophoresis and chromatographic separation of compounds from solution. In this study, the surface thermodynamic properties of selected chromatographic papers were determined with and without surfactant treatment. After the surface of the papers was coated with surfactant, the surface became more hydrophobic as revealed by a decrease in surface free energy components and parameters. The anionic surfactant had the largest effect on decreasing the apolar surface free energy component and the polar Lewis base parameter. The results show that the surface features of the chromatographic papers can be tailored for different needs using different surfactant treatments. (C) Koninklijke Brill NV, Leiden, 2009