Stability of Monolithic MOF Thin Films in Acidic and Alkaline Aqueous Media
Tawheed Hashem,
Elvia P. Valadez Sanchez,
Evgenia Bogdanova,
Anna Ugodchikova,
Alaa Mohamed,
Matthias Schwotzer,
Mohamed H. Alkordi,
Christof Wöll
Affiliations
Tawheed Hashem
Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
Elvia P. Valadez Sanchez
Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
Evgenia Bogdanova
School of Nuclear Science & Engineering, National Research Tomsk Polytechnic University, Lenina Avenue 30, 634050 Tomsk, Russia
Anna Ugodchikova
School of Nuclear Science & Engineering, National Research Tomsk Polytechnic University, Lenina Avenue 30, 634050 Tomsk, Russia
Alaa Mohamed
Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
Matthias Schwotzer
Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
Mohamed H. Alkordi
Center for Materials Science, Zewail City of Science and Technology, October Gardens, 6th of October, 12578 Giza, Egypt
Christof Wöll
Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
In the context of thin film nanotechnologies, metal-organic frameworks (MOFs) are currently intensively explored in the context of both, novel applications and as alternatives to existing materials. When it comes to applications under relatively harsh conditions, in several cases it has been noticed that the stability of MOF thin films deviates from the corresponding standard, powdery form of MOFs. Here, we subjected SURMOFs, surface-anchored MOF thin films, fabricated using layer-by layer methods, to a thorough characterization after exposure to different harsh aqueous environments. The stability of three prototypal SURMOFs, HKUST-1, ZIF-8, and UiO-66-NH2 was systematically investigated in acidic, neutral, and basic environments using X-ray diffraction and electron microscopy. While HKUST-1 films were rather unstable in aqueous media, ZIF-8 SURMOFs were preserved in alkaline environments when exposed for short periods of time, but in apparent contrast to results reported in the literature for the corresponding bulk powders- not stable in neutral and acidic environments. UiO-66-NH2 SURMOFs were found to be stable over a large window of pH values.
