The solubilities of seven alkanes in a matrix of uncrosslinked polystyrene were measured at several different temperatures. A gravimetric method reported earlier was used to monitor the sorption of the solvents. The experimental measurements showed unambiguously that the solubility of the alkanes diffusing into a polystyrene matrix reached a constant and reproducible value typical for each system and temperature. These values could be interpreted very well with the Flory-Huggins solubility parameter (chi = a(entropic contribution to x) + b(enthalpic contribution to x)/T[absolute temperature in Kelvin (K)]) or with the van't Hoff equation (In K-S = Delta S/R(gas constant) -Delta H/RT, where KS is the equilibrium constant, AS is the entropy change, and Delta H is the enthalpy change). (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 2393-2398, 2008