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MSE Seminar: “Ion Transport in Hydrated Anion Conducting Polyelectrolytes” – Paul F. Nealey – Pritzker School of Molecular Engineering of the University of Chicago, Senior Scientist at Argonne National laboratory
December 4 at 10:30 AM - 12:00 PM
The realization of next-generation electrochemical technologies demands anion-conducting polymers that break the fundamental trade-offs between conductivity, stability, and swelling. Ion transport in these materials is a complex, emergent property that arises from the coupling of water dynamics, nanoscale morphology, and polymer chemistry across multiple length and time scales.
In this talk, I will present a unified mechanistic picture of ion motion in a versatile family of polynorbornene-based polyelectrolytes. We have developed a multiscale framework that integrates simultaneous measurements of ion transport and water uptake in thin films with advanced spectroscopy, scattering, and molecular dynamics simulations. This approach enables us to directly connect local solvation dynamics on sub-picosecond time scales to the formation of a percolated, water-mediated network that governs macroscopic conductivity.
The first part of the talk I focus on how water facilitates ion transport across different conductivity regimes, revisiting long-standing concepts such as vehicular diffusion. I then show how the interplay between water-enabled transport and the thermodynamics of water uptake produces an unexpected convergence in conductivity across polymers with different ion-exchange capacities. Building on this insight, in the second part I demonstrate a strategy to overcome the usual relationship between transport and swelling. By engineering polymers with spatial charge density fluctuations, it is possible to decuple percolation from bulk water content and achieve high conductivity even at substantially reduced water and charge concentrations. These findings establish a mechanistically grounded design principle for anion-conducting polymers that achieve high performance while maintaining mechanical and chemical resistance.
Paul F. Nealey
Brady W. Dougan Family Professor in Molecular Engineering at the Pritzker School of Molecular Engineering of the University of Chicago, and a Senior Scientist at Argonne National laboratory
Paul F. Nealey is currently the Brady W. Dougan Family Professor in Molecular Engineering at the Pritzker School of Molecular Engineering of the University of Chicago, and a Senior Scientist at Argonne National laboratory. His research interests include nanofabrication techniques based on advanced lithography and directed self-assembly, dimension dependent material properties of nanoscopic macromolecular systems, quantitative three-dimensional characterization of the structure and dynamics of soft materials, and charge transport in nanostructured polymers. He is a fellow of the American Physical Society and a member of the National Academy of Engineering.