Molecular Simulations of Water Vapor Adsorption in Hygroscopic Polymer-Solvent Mixtures
ORAL
Abstract
Advanced polymer-based desiccants have the ability to adsorb water vapor for dehumidification and atmospheric water harvesting applications. Molecular simulations are conducted to study water vapor adsorption in pure polyacrylamide and polyacrylamide-glycerol mixtures. Molecular dynamics and Monte Carlo simulations are used to elucidate the coupling behavior between vapor adsorption and polymer chain structures at 298 K. The polymer chain conformations, radial distribution functions, and pore size distributions in the polymer are analyzed to understand the effects of glycerol and water on plasticizing the polyacrylamide. The effects of adsorption induced swelling is seen to have a large effect on the adsorption isotherms of polymer systems, especially in the higher relative humidity range. The addition of glycerol leads to the polyacrylamide to have a more swollen initial state before adsorption and enhance vapor adsorption due to its high hygroscopy.
*This research was performed under an appointment to the Building Technologies Office (BTO) IBUILD- Graduate Research Fellowship administered by the Oak Ridge Institute for Science and Education (ORISE) and managed by Oak Ridge National Laboratory (ORNL) for the U.S. Department of Energy (DOE). ORISE is managed by Oak Ridge Associated Universities (ORAU). All opinions expressed in this paper are the author's and do not necessarily reflect the policies and views of DOE, EERE, BTO, ORISE, ORAU or ORNL.
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Presenters
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James H Zhang
- Massachusetts Institute of Technology MIT