Degradation of a fuel cell membrane, as revealed by micro-Raman spectroscopy

We report a micro-Raman spectroscopic study of a fuel cell membrane subject ed to fuel cell testing until a significant decline in efficiency was noted . The membrane, poly(vinylidene fluoride)-graft-poly(styrene sulfonic acid) , PVDF-g-PSSA, was produced by electron irradiation of a PVDF film, graftin g with polystyrene and subsequent sulfonation. Depth profiles show that sev ere degradation due to loss of polystyrene sulfonic acid has occurred durin g the fuel cell run. The remaining amount of polystyrene sulfonic acid is o f the order of 5-10% of the initial content. Confocal Raman spectroscopy is found to be an excellent tool for investigating the changes in membrane co mposition after fuel cell experiments. (C) 2000 Elsevier Science Ltd. All r ights reserved.