Atomistic Insight into the Interfacial Structuring of ZIF-67 MOF/Polymer Composites and Their Propylene–Propane Adsorption Properties

Herein, we present a systematic computational study on a series of ZIF-67/polymer composites to reveal how the surface functionalization of the ZIF-67 with carbene groups and the nature of the polymers affect the structuring of the MOF/polymer interface and the resulting interfacial interactions as well as their thermodynamic propane and propylene adsorption properties. Hence, the surface-functionalized ZIF-67 nanoparticles with 1,3-bis(2,4,6-diisopropylphenyl)imidazole-2-ylidene (IDip) were predicted to improve the compatibility of the ZIF-67/6FDA-DAM composite enabling a better packing of the polymer at the MOF surface. The sorption simulations confirmed that the propylene/propane separation by these composites is not thermodynamically driven. Composites made of ZIF-67 and 6FDA-DABA as well as PIM-1 were then typically considered to gain an in-depth understanding of the role of the polymer on the MOF/polymer compatibility. We found that the ZIF-67/PIM-1 composite shows a better compatibility vs the ZIF-67/6FDA-DAM composite because the conformation of PIM-1 provides a better way to conform the polymer chains at the MOF surface.