Polymers behave very differently in thin, supported films as compared to the bulk, free-standing membranes. This is because, in thin films, polymer behavior is highly governed by different interfaces. It is just the last decade when interfaces of ion-conducting polymers and catalysts at electrodes became a high point of interest since interfacial interactions and ion transport limitations can limit the power density and performance of hydrogen fuel cells. To know about the distribution of mass or density across ionomer films, sophisticated techniques, like neutron reflectometry and X-ray computed tomography have been relied on. However, the ion conduction properties which can greatly vary from the substrate-to-air interface, are still reported as an average value for an entire sample using electrochemical impedance spectroscopy. We realized the need and thus developed a fluorescence confocal microscopy-based strategy to explore depth-specific ion conduction and stiffness behavior within ionomer bulk membranes and thin films. Additionally, we attempted to tweak the observed distribution of ionic conduction behavior across proton-conducting ionomer films <i>via </i>altering the interfacial structure. Such understanding can provide new tools or pave new paths to modify the interfacial behavior and minimize interfacial ion transport limitations at electrode layers of sustainable energy technologies and many more.

Exploring and tweaking the heterogeneous distribution of ionic conduction environment across ionomeric materials

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.