Four lots of cellulose acetate (CA) membranes, modified with polyacrylic acid, using various plasticizers, and coated with polyaniline (PANT) were prepared. The morphology of the membranes was evaluated by using scanning electron microscopy, and the membranes showed larger pore size when the plasticizers were used. The electrical conductivity of the modified membranes and coated with PANT increased by two orders of magnitude when the plasticizer triphenyl phosphate was used. The strain at break improved by an order of magnitude and the glass transition temperature (T-g) showed an average decrease of 36 degrees C when the membranes were plasticized. Finally, these membranes were tested as ion-exchange materials of a gold-iodide complex. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 1216-1224, 2009