am8b20570_si_001.pdf (1.33 MB)
Unraveling the Interfacial Structure–Performance Correlation of Flexible Metal–Organic Framework Membranes on Polymeric Substrates
journal contribution
posted on 2019-01-10, 00:00 authored by Jingwei Hou, Putu D. Sutrisna, Tiesheng Wang, Song Gao, Qi Li, Chao Zhou, Shijing Sun, Hao-Cheng Yang, Fengxia Wei, Michael T. Ruggiero, J. Axel Zeitler, Anthony K. Cheetham, Kang Liang, Vicki ChenPure
metal–organic framework (MOF) layers deposited on porous
supports are important candidates for molecular sieving membranes,
but their performance usually deviates from theoretical estimations.
Here, we combine step-wise scanning electron microscopy imaging, time-resolved
synchrotron X-ray scattering, terahertz infrared spectroscopy, and
density functional theory calculation to investigate the ZIF-8 membrane
formation on two types (polydopamine and TiO2) of functionalized
porous supports. Though molecular sieving of ZIF-8 membranes for smaller
gases (He, H2, and CO2) can be achieved with
both types of functionalized supports, we unravel that the strong
interaction between MOF and polydopamine can disrupt the formation
of “perfect” MOF crystals at the interface, leading
to a “contracted” MOF structure with partially uncoordinated
imidazolate ligands. This further affects the low-frequency dynamical
parameters of the framework and inhibits the effective seeded growth.
Eventually, it leads to an unexpected loss of selectivity for the
bulkier gases (N2 and CH4) for ZIF-8 on polydopamine-functionalized
supports. This work links the dynamical aspects of MOFs with their
gas transport behavior and highlights the importance of regulating
the interfacial weak forces to preserve the ideal molecular sieving
efficiency of MOF membranes, which also provides guidance for defect
engineering of MOF film fabrication for sensing and electronic devices
beyond membranes.
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theory calculationbulkier gasesN 2ZIF -8H 2CO 2defect engineeringuncoordinated imidazolate ligandsgas transport behaviorCH 4MOF film fabricationMOF membranesstep-wise scanning electron microscopy imagingtime-resolved synchrotron X-raysieving efficiencyTiO 2ZIF -8 membraneswork linksZIF -8 membrane formationsieving membranes
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