Phase-transformable metal-organic polyhedra for membrane processing and switchable gas separation
Po‐Chun Han, Chia‐Hui Chuang, Shang‐Wei Lin, Xiangmei Xiang, Zaoming Wang, M. Kuzumoto, Shun Tokuda, T. Tateishi, Alexandre Legrand, Min Ying Tsang, Meihua Yang, Kevin C.‐W. Wu, Kenji Urayama, Dun‐Yen Kang, Shuhei Furukawa
Abstract
The capability of materials to interconvert between different phases provides more possibilities for controlling materials’ properties without additional chemical modification. The study of state-changing microporous materials just emerged and mainly involves the liquefication or amorphization of solid adsorbents into liquid or glass phases by adding non-porous components or sacrificing their porosity. The material featuring reversible phases with maintained porosity is, however, still challenging. Here, we synthesize metal-organic polyhedra (MOPs) that interconvert between the liquid-glass-crystal phases. The modular synthetic approach is applied to integrate the core MOP cavity that provides permanent microporosity with tethered polymers that dictate the phase transition. We showcase the processability of this material by fabricating a gas separation membrane featuring tunable permeability and selectivity by switching the state. Compared to most conventional porous membranes, the liquid MOP membrane particularly shows the selectivity for CO2 over H2 with enhanced permeability. The capability of materials to interconvert between phases enables greater control over properties without additional chemical modification but can result in a sacrifice of porosity. Here, the authors synthesize metal-organic polyhedra that interconvert between the liquid-glass-crystal phases and develop a membrane with enhanced porosity and CO2 selectivity.