Structuring Metal–Organic Framework Materials into Hierarchically Porous Composites through One‐Pot Fabrication Strategy

Abstract

Controlled synthesis of metal–organic framework (MOF)‐based materials with multiple levels of porous structures across different length scales is of great interest in various applications but it still remains challenging. Most of the current strategies are time consuming and labor intensive, and not readily scaled‐up. In this work, we introduce a straightforward one‐pot fabrication strategy to prepare a robust and flexible hierarchically macro‐meso‐micro porous HKUST‐1/polyvinylidene fluoride (PVDF) composite through solvent evaporation, in which MOF crystallization and polymer precipitation are combined together. The effect of the MOF precursor and the polymer initial amount on the morphology of the final composite was thoroughly studied. The interaction between the MOF and the polymer during the evaporation process is the key factor, which would limit the mobility of the polymer chains and cause instability in the MOF growth, thus endowing the composite with a hierarchically macro‐meso‐micro porous structure. This “all‐in‐one” porous structure could enhance the mass transport property of molecules within the composite. The obtained HKUST‐1/PVDF composite showed an enhanced CO2 adsorption rate constant of 0.821 min−1 (298 K, 1 bar), which was 3.5 times higher than that of the pristine MOF. In addition, the composite showed an equivalent gas adsorption capacity under all tested pressures and greatly improved water stability.

Fabrication of Metal–Organic Framework/Polymer Composites via a One-Pot Solvent Crystal Template Strategy

“…The macroporous network in a polymer matrix has been proven to improve the diffusion rate of guest molecules and the accessibility of MOF particles. , In this work, the hierarchically porous ZIF-8/PU(2) composite was used to adsorb LY from wastewater. For comparison, the adsorption behaviors of PU and pristine ZIF-8 powder were also evaluated, as shown in Figure .…”

Design of Hierarchical Architectures in Metal–Oganic Frameworks for Catalysis and Adsorption

“…This combination generates a hierarchical macro–meso–microporous structure in the final polymer/MOF composite. The authors claimed that the framework instability created during the MOF growth as a result of MOF–polymer interactions is the driving force for the creation of a multipore HKUST-1 (with pore sizes range from 50 nm to 3 μm) as evident from the mercury intrusion porosimetry characterization . Both HKUST-1 and the polymer matrix are highly compatible, showing no phase segregation, i.e., bulk polymer or MOF.…”

“…The authors claimed that the framework instability created during the MOF growth as a result of MOF−polymer interactions is the driving force for the creation of a multipore HKUST-1 (with pore sizes range from 50 nm to 3 μm) as evident from the mercury intrusion porosimetry characterization. 126 Both HKUST-1 and the polymer matrix are highly compatible, showing no phase segregation, i.e., bulk polymer or MOF. The porosity of the MOF/polymer composite was confirmed by N 2 physisorption analysis, revealing a BET area of 527 m 2 •g −1 and a pore volume of 0.3 cm 3 •g −1 .…”

ZIF-8 integrated with polydopamine coating as a novel nano-platform for skin-specific drug delivery

“…12 Structurally, they are composed of organic bridging ligands and metal ions or metal clusters, which can be connected to each other via coordination into three-dimensional frameworks. 13,14 By altering the types of either the organic ligand or the metal ions, different MOF structures can be obtained, among which the zeolitic imidazolate framework-8 (ZIF-8) with high chemical and thermal stability has shown great versatility for applications in a variety of fields. 15 It is a kind of porous crystalline material built from 2-methylimidazole (2MI) and Zn 2+ .…”