Water sorption and swelling of very thin Nafion membranes

G. ABUIN; M. C. FUERTES; H. CORTI

Salta

Congreso; VIII Congreso Ibero-Americano en Ciencias y Tecnología de Membranas (CITEM-2012); 2012

Nafion ionomers, the product of copolymerization of perfluorosulfonate vinyl ether and tetrafluoroethylene, is the most used proton exchange membrane (PEM) in PEM fuel cells as well as in electrolyzers and other electrochemical devices. The performance of PEM fuel cells is largely determined by the structure of the membrane electrode assembly (MEA), more specifically, by the molecular architecture of the three-phases region. Roughly, the expected thickness of the Nafion film covering the catalyst particles can fluctuate from few nm up to 500 nm. The main objective of this work is to compare the sorption and swelling properties of casted Nafion nanofilms, supported on a solid surface, with that observed in bulk Nafion membrane used in PEM fuel cell MEAs. This point is relevant for molecular models describing transport properties in the three-phases region, aiming to optimize the PEM fuel cell performance by means of molecular design using model parameters. As far as we know, there is a lack of information on the properties of Nafion thin films, as those covering the catalyst particles in the three-phases region, and the current models of transport in Nafion-based fuel cells rely on the properties of bulky membranes.