Organic-organic pervaporation was studied for high free volume material-amorphous Teflon AF2400 (copolymer of 2,2-bis-trifluoromethyle-4,5-difluoro dioxole and tetrafluoroethylene). Individual organic components-acetone (A), chloroform (Ch) and methanol (M) that are capable of forming azeotrope mixtures as well as binary mixtures A-Ch and M-Ch were tested as penetrants. The process was studied at different temperatures (10-50 degrees C) over a wide range of composition of mixtures (10-90%). Evidence of formation of associates between the components in the mixtures in the liquid phase and during mass transfer through the films were obtained. IR spectra and quantum-chemical calculations supported these conclusions. (c) 2005 Elsevier B.V. All rights reserved.