The “Rigid‐Flexible Coupling” Blueprint: Chemically Welded MOF/Polyimide Porous Hybrids for Multifunctional Separations

The 2025 Nobel Prize in Chemistry, awarded for pioneering contributions to metal–organic frameworks (MOFs), underscores their revolutionary impact and growing importance in advanced separation technologies. Hybrid porous media that integrate crystalline MOFs within polyimide matrices represent a state‐of‐the‐art platform for tackling the global water‐energy nexus. Nevertheless, their practical performance is often constrained by interfacial incompatibility and inherent structural trade‐offs between rigidity and flexibility. This review establishes a unified “rigid‐flexible coupling” design paradigm, systematically dissecting interfacial engineering strategies that convert weak physical interactions into chemically welded interfaces via covalent grafting, hydrogen bonding, and defect‐mediated coordination. Particular focus is given to the dimensional evolution from two‐dimensional mixed‐matrix membranes to three‐dimensional hierarchical aerogels, which signifies a pivotal shift in mass transport from diffusion‐controlled to convection‐dominated regimes. Building on this framework, the review elucidates how hierarchical architectures enable multifunctional capabilities, including selective ion separation through Donnan exclusion, Janus‐wettability‐governed multiphase separation, and photothermal‐assisted remediation of high‐viscosity crude oil. Finally, it distills materials design principles and discusses emerging frontiers in artificial‐intelligence‐driven materials discovery and four‐dimensional‐responsive systems. By bridging interfacial chemistry, structural hierarchy, and transport physics, this review offers a comprehensive blueprint for the rational design of next‐generation hybrid porous media for sustainable environmental technologies.