Langmuir 2019, 35,10390-10396
Formation of Metal-Organic Frameworks on Metal Ion-Doped Polymer Substrate: In_Depth Time-Course Analysis using Scanning Electron Microscopy
Takaaki Tsuruoka,* Manami Hata, Shoya Hirao, Takashi Ohhashi, Yohei Takashima, and Kensuke Akamatsu*
The growth of metal-organic frameworks (MOFs) on a metal ion-doped polymer as a precursor and support substrate was investigated based on mechanistic and kinetic analyses. The studies were performed by varying the reaction temperature and the concentrations of the organic ligand and nucleation-promoted additive. Using the NH2-MIL-53 (Al) framework as a model system, a systematic study of the mechanism of formation of tetragonal- and rod-shaped NH2-MIL-53 (Al) crystals on the substrate was performed. The nucleation rate in the early stage of the reaction is a major factor in determining the surface morphology of the resultant NH2-MIL-53 (Al) crystal films, as confirmed by changing the concentration of organic ligands and by employing pyridine additives. These results provide fundamental understanding of the influence of the nucleation rate on the ability to control the morphology and structure of MOF crystal films.