Ion-conducting polymers are used in most solid-state energy-conversion and storage devices. These materials must conduct the ions in a mechanically robust matrix that inhibiting reactant and product crossover. The performance and durability of the membranes are related to their properties governed by the physiochemical interactions between chemical structure, water uptake, and morphology. In addition, these ionomers are found as nanometer-thick electrolyte films within fuel-cell porous electrodes wherein electrochemical reactions occur. Throughout this thickness range, interactions with the environment and substrate control the intrinsic morphology of the ionomer and its transport properties. Only by understanding such interactions, can one truly begin to optimize the material functionalities, operating parameters, and system design  This talk focuses on this structural characterization for perfluorosulfonic-acid (PFSA) ionomers in various environments using X-Ray scattering (XS) technique. The structure/function relationship of these materials relies on their morphology derived from a nano-phase separation of hydrophilic ionic domains and hydrophobic backbone, which control the transport and mechanical properties, respectively. The morphology and sorption kinetics of the membrane are investigated at various time scales to probe the dynamic nature of the structure/function relationship. In addition, time-resolved grazing-incidence x-ray scattering (GIXS) is employed to understand the morphology of the ionomer as a thin film on various substrates and subjected to different annealing conditions.

Study of PFSA ionomers using X-ray scattering techniques

248th National Meeting (2014)

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