title: Statistical mechanical model of gas adsorption in porous crystals with dynamic moieties.
abstract: Some nanoporous, crystalline materials possess dynamic constituents, for example, rotatable moieties. These moieties can undergo a conformation change in response to the adsorption of guest molecules, which qualitatively impacts adsorption behavior. We pose and solve a statistical mechanical model of gas adsorption in a porous crystal whose cages share a common ligand that can adopt two distinct rotational conformations. Guest molecules incentivize the ligands to adopt a different rotational configuration than maintained in the empty host. Our model captures inflections, steps, and hysteresis that can arise in the adsorption isotherm as a signature of the rotating ligands. The insights disclosed by our simple model contribute a more intimate understanding of the response and consequence of rotating ligands integrated into porous materials to harness them for gas storage and separations, chemical sensing, drug delivery, catalysis, and nanoscale devices. Particularly, our model reveals design strategies to exploit these moving constituents and engineer improved adsorbents with intrinsic thermal management for pressure-swing adsorption processes.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94709.
authors.forename: Cory M
authors.identifier: 0000-0002-8181-9178
authors.initials: CM
authors.lastname: Simon
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94709.
authors.forename: Efrem
authors.initials: E
authors.lastname: Braun
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94709; carraro@berkeley.edu Berend-Smit@Berkeley.edu.
authors.forename: Carlo
authors.initials: C
authors.lastname: Carraro
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94709; carraro@berkeley.edu Berend-Smit@Berkeley.edu.|Laboratory of Molecular Simulation, Institut des Sciences et Ingénierie Chimiques, Valais Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1951 Sion, Switzerland.
authors.forename: Berend
authors.initials: B
authors.lastname: Smit
keywords: flexible metal–organic frameworks; gas storage; metal–organic frameworks; porous materials; statistical mechanics