Interconnected Porous Monolith Prepared via UiO‐66 Stabilized Pickering High Internal Phase Emulsion Template

Abstract

High internal phase emulsion (HIPE) templating offers an efficient approach to prepare 3D hierarchical porous metal-organic framework (MOF)-based monoliths. However, conventional poly-Pickering HIPEs synthesized from MOF-stabilized HIPEs have low permeability due to closed-cell structures, thus limiting their applications. Herein, interconnected porous MOF monoliths, prepared by adding a small amount of polyvinyl alcohol (PVA) as co-stabilizer into UiO-66 stabilized Pickering HIPE templates are reported. The morphology of the porous monoliths was studied by scanning electron microscopy (SEM). The pore size could be well controlled by varying the PVA concentration. A unique morphology, formed by an ice template, was clearly seen on the cell wall. The pores were thus interconnected. The mass transfer performance of the monoliths having different cell structures was investigated by CO adsorption. The interconnected porous structure significantly accelerated the CO adsorption process, as well as enhancing the saturated adsorption capacity.

Recent advances in the synthesis of monolithic metal-organic frameworks

“…Consequently, the composite showed a slightly enhanced water uptake capacity when compared with HIPE. Fortunately, the pore blocking effect was resolved by Wang et al [78] by adding a small amount of poly(vinyl alcohol) (PVA) as the stabilizer when preparing monolithic MOFs.…”

Hierarchically Porous Monolith with High MOF Accessibility and Strengthened Mechanical Properties using Water‐in‐Oil High Internal Phase Emulsion Template

“…Most of the brighter water droplets were spherical, like those of the UiO‐66/PVA stabilized HIPEs. [ 26,27 ] These emulsions were still stable after 1 week with no obvious phase separation. However, further addition of internal phase to 88 vol% resulted in phase separation of the HIPE, similar to the HIPEs stabilized by silica.…”

“…[ 25,26 ] We further introduced a co‐stabilizer to manipulate the porous structure and studied the adsorption kinetics of guest molecules within the prepared MOF/poly‐HIPEs. [ 27 ] Although these hierarchically porous MOF composites exhibited improved mass transfer behaviors, some particles were buried in the polymer matrix after polymerization, leading to a significant decrease in MOF accessibility. [ 27,28 ] Moreover, most of the MOF monoliths prepared via this interfacial technique were based on O/W HIPEs, which limits the choice of monomers to a few water‐soluble ones and, more importantly, results in poor mechanical properties of the prepared MOF/poly‐HIPEs.…”

Simultaneous phase change energy storage and thermoresponsive shape memory properties of porous poly(vinyl alcohol)/phase change microcapsule composites

“…), pure polymer materials (poly(vinyl alcohol) (PVA), polyurethane, etc.) and carbonaceous materials 30 can be prepared by the emulsion template method, 31 freeze-drying method, 32 supercritical CO 2 foaming method 33 and physical stirring and foaming method. 34 Attributed to good biocompatibility, hydrophilicity, easy degradation and modification, porous PVA has been successfully applied as adsorption materials in filtration 35 and oil-water separation, 36 and as medical materials in drug release, 37 tissue engineering scaffolds 38 and wound dressings.…”