Comparison of three methods for the determination of the electrical conductivity of ion-exchange polymers

The development of ion-exchange membranes techniques using an electrical potential gradient incite often to define the electrical conductivity of this category of functional polymers. The investigation methods of this conductivity did not stop to vary, to such a point that some results can be contradictory. So we have determined this dynamic characteristic in comparing three recent methods. This has been done with three ion-exchange membranes often used in industrial applications: CM1 and CM2. made from sulfonated and crosslinked polystyrene, and Nafion(R) 117 made from sulfonated uncrosslinked polytetrafluoroethylene. Measurements were achieved in sodium chloride solutions, at concentrations from 0.1 to 2 mol l(-1). The results show, whatever the polymer microstructure, non-negligible disparities between the three methods. (C) 2002 Elsevier Science Ltd. All rights reserved.