Nanomechanical Characterization of Fuel Cell Ionomers

Energy sustainability can be achieved by improving and adopting clean energy technologies, and a better nanoscale understanding of ionomer-catalyst layers could lead to increased efficiency of proton exchange membrane fuel cells. Samples of Nafion ( Perfluorosulfonic acid ionomer) and PFIA (Perfluoroimide acid ionomer) of varying film thickness were prepared and then studied using contact resonance force microscopy. It was determined that storage and loss modulus increase as relative humidity increases and ionomer film thickness goes below 100 nm. Furthermore, in this specific study, the similar storage and loss modulus of Nafion and PFIA could be attributed to similar backbone structure and only slightly different flexibility of side chains. In addition, relative humidity was found to have a significant impact on viscoelastic properties and will need to be controlled in the future in order to learn more about ionomer behavior on the nanoscale