Preserving Mesoporosity in Type III Porous Liquids through Dual-layer Surface Weaving

초록

The fundamental limitation for pore preservation in a Type III porous liquid (T3PL) is the need for a small aperture from the porous filler to realize size exclusion of a bulky solvent. We present a dual-layer surface weaving strategy that can disregard this limitation and achieve micro- and mesoporous metal-organic framework (MOF)-based T3PLs even with apertures much larger than the solvent molecules. By first weaving a tight network of poly(tert-butyl methacrylate) on the MOF surface, the poly(dimethylsiloxane) (PDMS) solvent can be effectively excluded from the pores while smaller guest molecules such as CO2, C2H4, and H2O can freely access the interior, as confirmed by low-pressure adsorption isotherms. Further application of a PDMS-containing polymer coating helps lower the viscosity of the PL due to increased particle dispersibility. This strategy has resulted in the successful construction of T3PLs with aperture sizes up to 3.1 nm. This work reported a dual-layer surface weaving strategy on metal-organic frameworks (MOFs) to realize Type III porous liquids (PLs) with apertures larger than the solvent molecules. The 1st polymer layer, cross-linked poly (t-butyl methacrylate), serves as a physical barrier to block the solvent molecules from entering the MOF pore. The 2nd layer uses a solvent-compatible polymer to reduce PL viscosity. As a result, a PL bearing a 3.1 nm aperture was successfully constructed. image

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