Blends of high impact polystyrene (HIPS) and polyaniline (PAni) were obtained with the aim of producing membranes for electrodialysis. The characterisation of membranes was done by swelling, ion-exchange capacity, thermogravimetric (TGA) and dynamic mechanical (DMA) analysis. Chemical stability in acidic, alkaline and oxidising media was evaluated to choose the more appropriate solution for electrodialysis. The results of transport numbers and percent extraction obtained using these membranes were compared to those obtained with the commercial membrane Nation 450. The thermogravimetric analysis showed that the membranes do not suffer degradation before 230degreesC. After the electrodialysis, it was verified that membranes presented a good zinc ion transport as well as percent extraction compared to the commercial membrane Nafion 450. (C) 2004 Elsevier B.V. All rights reserved.