Perfluorosulfonic acid ionomers (PFSAs) are the benchmark materials used as proton-exchange membranes (PEMs) in fuel cells. Typical PFSA membranes have a chemical structure consisting of a PTFE backbone with perfluoroether side chains containing a pendant sulfonic acid group. The complex, phase-separated morphology of PFSAs has been the focus of many investigations aimed at exploring the effect of processing conditions and sidechain structure on the morphology and thermomechanical transitions of these ionomers. In this study, we aim to investigate the effect of an additional acidic site in the sidechain on the morphology and properties of perfluoroimide acid ionomers (PFIA). Utilizing alkylammonium counterions allows for systematic control of ionic interactions within PFIA according to the chain length of the ions, which can be probed by applying techniques such as dynamic mechanical analysis (DMA) and thermomechanical analysis (TMA). Morphology and thermal transitions of multi-acid PFIA compared to single-acid PFSA are also investigated by small angle x-ray scattering (SAXS) and DSC to determine the dependence of sidechain structure on the morphology and properties of perfluorinated ionomers.

Dependence of sidechain structure on the morphology and properties of perfluorinated ionomers

255th National Meeting (2018)

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