@article{d443018dabf346339b7d3f37854e2b3e,
title = "Dynamic Emergence of Nanostructure and Transport Properties in Perfluorinated Sulfonic Acid Ionomers",
abstract = "The role of fluoropolymer physicochemical properties in the dynamic evolution of nanostructure and ionic conductivity in perfluorinated sulfonic acid ionomer thin films was investigated by in situ water sorption experiments. The properties and mass fraction of the ionomer matrix were systematically varied between Nafion and a perfluorodioxolane ionomer with the same sulfonic acid side chain and mass fractions ranging from 0.26 to 0.57. Swelling rate constants attributed to Fickian mass transport (∼10-2 s-1) decreased with increasing ionic strength and humidity (i.e., with increased swelling) while rate constants associated with morphological rearrangement (∼10-3 s-1) increased. The rate of deformation, in nm s-1, was primarily dictated by the matrix segmental mobility. Transient hydration-driven conductivity exhibited a single rate constant (∼10-3 s-1) corresponding to the morphological process. In situ grazing incidence X-ray scattering experiments reveal a rapid formation of ionomer domains during Fickian water sorption, followed by a slower ordering of these domains during hydration. This relationship between the rates of swelling and morphological changes confirm/pinpoint transient changes controlling ion conduction mechanisms in ionomer thin films. ",
author = "Adlai Katzenberg and Debdyuti Mukherjee and Dudenas, {Peter J.} and Yoshiyuki Okamoto and Ahmet Kusoglu and Modestino, {Miguel A.}",
note = "Funding Information: P.J.D. and Ahmet Kusoglu acknowledge the funding from the U.S. Department of Energy Fuel Cell Technologies Office (contract no. DE-AC02-05CH11231). This work also made use of facilities at the Advanced Light Source Beamline 7.3.3, supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy (contract no. DE-AC02-05CH11231). This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education (ORISE) for the DOE. ORISE is managed by ORAU under contract no. DE-SC0014664. This research used beamline 11-BM (CMS) of the National Synchrotron Light Source II and the Center for Functional Nanomaterials (CFN), U.S. Department of Energy (DOE) Office of Science User Facilities operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. We thank Dr. Esther Tsai and Dr. Ruipeng Li for their assistance in performing experiments at beamline CMS. This work made use of facilities at the Joint Center for Artificial Photosynthesis supported through the Office of Science of the U.S. Department of Energy under award number DE- SC0004993. This work was performed in part at the Advanced Science Research Center NanoFabrication Facility of the Graduate Center at the City University of New York. The authors would like to acknowledge the financial support of NYU Tandon School of Engineering through M.A.M. startup fund. The authors would like to thank Dr. Meron Tesfaye for facilitating heated-cell ellipsometry measurements. Publisher Copyright: Copyright {\textcopyright} 2020 American Chemical Society.",
year = "2020",
month = oct,
day = "13",
doi = "10.1021/acs.macromol.0c01213",
language = "English (US)",
volume = "53",
pages = "8519--8528",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "19",
}