A new model for pervaporation of binary mixtures through rubbery polymeric membranes is proposed. The model deals with the inherent problem of plasticization in a very simple, but physically realistic manner, and consequently contains fewer parameters than prior models; thus, concentration profiles can be computed from a minimum of experimental results for pervaporation and sorption. Results from a series of ionically crosslinked poly(n-alkyl acrylate) membranes and toluene/i-octane binary mixtures are used to test the model. The model reasonably represents experimental results for pervaporative transport of toluene/i-octane mixtures through these membranes. Concentration profiles for the penetrants across the membranes are calculated from the model using experimental results and parameters obtained in the fitting process. (C) 2004 Elsevier B.V. All rights reserved.