Recast Nafion-117 thin film from water solution

Full Paper: Perfluorosulfonated ionomer (PFSI) dispersions in various solve nts, usually mixtures of organic compounds and water, were used to prepare the membrane-electrode system in polymer electrolyte membrane fuel cells (P EMFC), the aim being to increase performance by improving the triple contac t of graphite (electron conducting material), Pt (hydrogen dissociation cat alyst) and ionomeric membrane (proton conducting). When using PFSI dispersi ons in water-organic solvent mixture, care must be taken not to poison the Pt catalyst through organic decomposition products, a consequence of the th ermal treatment of the electrode-polymer system bonded with PFSI dispersion . In the present study some procedures for preparing Nafion water dispersio n, starting from a Nafion-117 membrane, are described. The morphological ch aracteristics of the prepared dispersions were compared with Nafion commerc ial dispersion (NCD). Moreover, membranes with a thickness of 5-20 mum were prepared and characterised, using both the obtained and the NCD dispersion s. The obtained data showed that Nafion water dispersion, which can be used to prepare the membrane/electrode system, results in thin membranes that a bsorb more water than NCD membranes, and have equal and/or higher proton co nduction than the NCD.