title: Microscopic Model of the Metal-Organic Framework/Polymer Interface: A First Step toward Understanding the Compatibility in Mixed Matrix Membranes.
abstract: An innovative computational methodology integrating density functional theory calculations and force field-based molecular dynamics simulations was developed to provide a first microscopic model of the interactions at the metal-organic framework (MOF) surface/polymer interface. This was applied to the case of the composite formed by the polymer of intrinsic microporosity, PIM-1, and the zeolitic imidazolate framework, ZIF-8, as a model system. We found that the structure of the composite at the interface is the result of both the chemical affinity between PIM-1 and ZIF-8 and the rigidity of the polymer. Specifically, there is a preferential interaction between the -CN groups of PIM-1 and the NH terminal functions of the organic linker at the ZIF-8 surface. Additionally, the resulting conformation of the polymer gives rise to interfacial microvoids at the vicinity of the MOF surface. The porosity, rigidity, and density of the interfacial polymer were analyzed and compared to those for the bulk polymer. It was shown that the polymer still feels the impact of the MOF surface even at long distances above 15-20 Å. Further, both the polydispersity of the polymer and the flexibility of the MOF surface were revealed to only slightly affect the properties of the MOF/interface. This work, which delivers a microscopic picture of the MOF surface/polymer interactions at the interface, would lead, in turn, to the understanding of the compatibility in MOF-based mixed-matrix membranes.
authors.affiliation: Institut Charles Gerhardt Montpellier UMR 5253 CNRS, Université de Montpellier , Place E. Bataillon, 34095 Montpellier Cedex 05, France.
authors.forename: Rocio
authors.initials: R
authors.lastname: Semino
authors.affiliation: Institut Charles Gerhardt Montpellier UMR 5253 CNRS, Université de Montpellier , Place E. Bataillon, 34095 Montpellier Cedex 05, France.|Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, UM, ENSCM , 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 05, France.
authors.forename: Naseem A
authors.initials: NA
authors.lastname: Ramsahye
authors.affiliation: Institut de Physique de Rennes, IPR, UMR 6251 CNRS , 263 Avenue du Général Leclerc, 35042 Rennes, France.
authors.forename: Aziz
authors.initials: A
authors.lastname: Ghoufi
authors.affiliation: Institut Charles Gerhardt Montpellier UMR 5253 CNRS, Université de Montpellier , Place E. Bataillon, 34095 Montpellier Cedex 05, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Maurin
keywords: MOF/polymer interface; density functional theory; microscopic model; mixed-matrix membranes; molecular dynamics