Unraveling the Enhancement of the Interfacial Compatibility between Metal–Organic Framework and Functionalized Graphene Oxide

Abstract

Advanced modeling and experimental characterization tools were coupled to gain an unprecedented in-depth characterization of the interface formed when a hybrid porous solid ZIF-8 is incorporated as filler onto an amine-functionalized graphene oxide (GO) matrix. As a preliminary stage, an aminopyridine-functionalized GO was synthesized, and a realistic atomistic model was computationally built integrating their structural and chemical features deduced from X-ray photoelectron spectroscopy and X-ray diffraction experiments. An atomistic representation of the ZIF-8/functionalized GO interface was further simulated and carefully analyzed in terms of the nature and the strength of interactions between the two components and the GO conformation with a special emphasis on the impact of the functionalization. It was revealed that grafting the aminopyridine function at the GO significantly enhances the interactions with the terminal functions present at the MOF interface associated with an in-depth penetration of the functionalized GO into the pockets of the ZIF-8. The so-predicted high compatibility between the two components was then supported by Infrared experiments collected on the prepared composite. Complementary transmission electron microscopy experiments further revealed a homogeneous dispersion of the ZIF-8 nanoparticles into the GO matrix with the absence of MOF agglomeration and mechanical testing evidenced a significant enhancement of the tensile strength for the corresponding composite. This fundamental exploration unambiguously demonstrates the key role played by the GO functionalization to achieve optimal interfacial MOF/GO properties, and this opens promising perspectives for processing thin films required for future applications.