@article{e97eecb449b14323965e1324735d0424,
title = "Water vapor sorption, diffusion, and dilation in polybenzimidazoles",
abstract = "Polybenzimidazoles (PBIs) have been investigated for use as gas separation membranes due to their thermal stability and good H2/CO2 separation performance at elevated temperatures. However, PBIs are hydrophilic, and effects of water vapor on PBI separation performance are essentially unexplored. This study investigates water sorption, diffusion, and dilation of a commercial PBI, Celazole, and a recently synthesized sulfonyl-containing PBI, TADPS-TPA. Water binds strongly to both polymers and requires elevated temperatures for removal. Water vapor sorption in Celazole follows dual-mode behavior up to unit activity, while upward concavity is observed at high activities in the TADPS-TPA sorption isotherm. Both PBIs swell significantly in water, and desorption hysteresis suggests water-induced conditioning of the PBI matrix. Model fits of dilation behavior enable estimation of partial molar volume and water-accessible fractional free volume (FFV) as a function of water activity. Water vapor diffusion coefficients increase with increasing vapor activity, which correlates with water-accessible FFV.",
author = "Moon, {Joshua D.} and Michele Galizia and Hailun Borjigin and Ran Liu and Riffle, {Judy S.} and Freeman, {Benny D.} and Paul, {Donald R.}",
note = "Funding Information: Joshua D. Moon: 0000-0002-4402-2362 Judy S. Riffle: 0000-0002-6291-6095 Benny D. Freeman: 0000-0003-2779-7788 Funding This study was partially supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences under Award DE-FG02-02ER15362. We gratefully acknowledge partial support of this work by the Australian−American Fulbright Commission for the award to B.D.F. of the U.S. Fulbright Distinguished Chair in Science, Technology and Innovation sponsored by the Commonwealth Scientific and Industrial Research Organization (CSIRO). This material is based upon work supported in part by the National Science Foundation Graduate Research Fellowship Program under Grant DGE-1610403 and in part by the National Science Foundation under Cooperative Agreement EEC-1647722. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Notes The authors declare no competing financial interest. Publisher Copyright: Copyright {\textcopyright} 2018 American Chemical Society. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.",
year = "2018",
month = sep,
day = "10",
doi = "10.1021/acs.macromol.8b01659",
language = "English",
volume = "51",
pages = "7197--7208",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "18",
}