The purpose of this study was to experimentally determine the effects of cationic contamination on PEMFC ionomers in order to elaborate characterization tools and new modes for pollution diagnosis. First, a large series of techniques were used to investigate the properties of commercial PFSA membranes. Distinctive parameters concerning structure and properties were extracted as well as theirrelationship to ion exchange capacity (IEC).Second, the thermal properties of cation-contaminated membranes revealed changes that are highly dependent on the Lewis Acid Strength of the cation (LAS). This trend was correlated with the nature of the interaction between the cations and the polar groups of the polymer chain, revealed byFTIR spectroscopy. Finally, the influence of the pollution level on the thermal and structural parameters allowed us to reveal not only the relevant parameters to the identification but also to the quantification o fpollution. An application of the different calibration curves was performed on aged membranes coming from real operating systems.
