Solubility parameters of water-soluble 2-(diethylamino)ethyl methacrylate (DEA) homopolymer and [2-(diethylamino)ethyl methacrylate]-[2-(dimethylamino) ethyl methacrylate] (DEA-DMA) diblock copolymer were analyzed by inverse gas chromatography and values were compared to the solubility parameters of 2-(dimethylamino) ethyl methacrylate (DMA) homopolymer. Sorption thermodynamic parameters of some aliphatic, alicyclic and aromatic hydrocarbons, weight fraction activity coefficients, Flory-Huggins interaction parameters and solubility parameters for both hydrocarbons and polymers were calculated. It was observed that sorption thermodynamic parameters on (co)polymers depend on the molecular structures of hydrocarbons. Evaluating both the calculated values of the weight fraction activity coefficients and Flory-Huggins interaction parameters, the solving ability of the hydrocarbons for DEA, DMA homopolymers and DEA-DMA diblock copolymer decreased in the following sequence: aromatic > alicyclic > aliphatic hydrocarbons. © 2008 Friedr. Vieweg & Sohn Verlag/GWV Fachverlage GmbH.