Coassembly of Pro-Labile Polymers and MOFs toward Tunable Hierarchy and Functionality

Integrating the functionality of polymers and hierarchical structures of metal-organic frameworks (MOFs) in porous materials is highly beneficial. In this study, porous MOF-polymer frameworks (MPFs) were efficiently coassembled using “pro-labile” polymers, aiming to achieve tunable hierarchy and enhanced functionality. Poly-γ-glutamic acid (γ-PGA), featuring cross-linkable carboxyl groups, was successfully incorporated to form mesoporous domains in the MPF-1 series. This required increasing molar ratios (up to 78%) of (NHC₄H₅OCO₂H)γ-PGA/BDC-NH₂ during coassembly. Additionally, the linear polyester polycaprolactone (PCL), with hydrolytically cleavable linkages, was employed to construct a functional micro/mesoporous architecture in MPF-2. Specific ammonia adsorption experiments were conducted to evaluate the framework’s stability under corrosive gas conditions and the accessibility of functional sites within the MPFs. Impressively, the incorporation of PCL enhanced the ammonia adsorption capacity to 12.0 mmol·g^-1 and improved the framework’s overall stability. The adsorption performance was closely linked to pore properties, surface area, accessible functional sites, and chemical stability. In summary, with the introduction of cross-linkable or cleavable polymers, the one-pot coassembly approach provides a valuable strategy to combine both advantages for practical applications.