Colloquium Series: How to Understand and Play with Nanoconfinement: A Polymer Perspective (Shudipto Dishari, University of Nebraska – Lincoln)

Abstract. In the era of electric cars, the importance of cutting-edge research to find solutions to the technical challenges of energy conversion and storage devices (such as fuel cells, batteries) can be easily realized. Ion-conducting polymers (ionomers) play a critical role in conducting ions in these devices. The mechanical and ion conduction properties of these ionomers can be very different in sub-micron thick films as compared to their bulk, several tens of micron thick, membrane counterparts. In a hydrogen fuel cell, the ion conduction limitation within the sub- micron thick ionomer layer can make the oxygen reduction reaction at the cathode sluggish. To address this ion conduction limitation, we need to first identify the issues associated with polymers under nanoconfinement and then control their nanoscale and interfacial behavior to find solutions to ion conduction limitations. Recently, we have developed fluorescence spectroscopy- and confocal microscopy-based innovative strategies to explore ion conduction environment and water-polymer mobility/stiffness along the depth of sub-micron thick ionomer films. We combined these findings with experimental observations from X-ray scattering, electron microscopy, quartz crystal microbalance, and electrochemical impedance spectroscopy to unravel the critical role played by the characteristics of ionic domains in weakening the ion conductivity across the films. This learning experience motivated us to design new ranges of bio- derived and nature-inspired ionomers to specifically address and minimize the ion conduction limitations in sub-micron thick films. The talk will cover our journey from learning to designing ionomers for fuel cells and beyond.

Biography. Dr. Shudipto Konika Dishari is an assistant professor in the Department of Chemical and Biomolecular Engineering at the University of Nebraska-Lincoln (UNL) in 2016. Dishari worked as a post-doctoral fellow in Chemical Engineering and Materials Science and Engineering at the Pennsylvania State University. She received her Ph.D. in Chemical and Biomolecular Engineering from the National University of Singapore. Dishari’s research focuses on designing synthetic and bio-derived, ion-conducting, and light-harvesting polymers and exploring their nanoscale properties. Her work targets to impact energy conversion/storage devices, chemical/biosensing, antimicrobial, and bioseparation applications. Dishari has received several honors and awards in recognition of her research and teaching excellence, including, DOE Office of Science Early CAREER Award (2019), NSF CAREER Award (2018), 3M Non-Tenured Faculty Award (2021), Emerging Innovator of the Year Award by NUTech Venture (2020), Harold and Esther Edgerton Junior Faculty Award (2019), Henry Y. Kleinkauf Family Distinguished New Faculty Teaching Award (2020), Baxter Young Investigator Award (2014) and more. Dishari has organized and chaired many symposiums at the national meetings organized by the American Chemical Society (ACS), American Institute of Chemical Engineers (AIChE), American Physical Society (APS), and North American Membrane Society (NAMS). She is also actively involved in UNL’s “Complete Engineering Initiative,” “Diversity and Inclusion Taskforce,” and Nebraska Center for Materials and Nanoscience’s “Education and Outreach Committee.”