Mixed-matrix membranes (MMMs) formed by incorporating metal-organic frameworks (MOFs) into polymers have a general limitation in that the MOFs are typically formed into rather simple dimensionalities (such as 1D, 2D, or 3D). Each design approach has intrinsic-albeit independent-benefits, such as network percolation (1D), access to high-aspect ratios (2D), and ease of processability (3D). However, a design strategy is needed to combine multiple dimensionalities and, thereby, access the full range of transport and compositing benefits of these high-performance materials. Herein, a facile method to form multi-dimensional HKUST-1 nanoparticles is introduced by using a modulator to tune the MOF nucleation and growth mechanism. At 30 wt % multidimensional MOF loading, the MMM shows CO2 permeabilities of approximately 2500 Barrer, which represents a 2.5-fold increase compared to that of a pure polymer without a large loss of selectivity for CO2 /CH4 and CO2 /N2 . Additionally, almost no plasticization pressure response is observed for CO2 up to 750 psi, suggesting an unusual stability to high activity feeds.
Keywords: HKUST-1; gas separation; metal-organic framework; mixed-matrix membranes; plasticization.
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