Microstructure-governed gas transport in hybrid membranes: Mechanisms, interfacial engineering, and pathways beyond traditional limits

Overcoming the traditional trade-off between permeability and selectivity in gas-separation membranes has been a central research objective, and the incorporation of inorganic materials into polymer matrices has emerged as a prominent and effective strategy. This work elucidates regulatory mechanisms from the microscale to macroscopic performance, highlighting the profound influence of inorganic materials on the microstructure and gas-transport properties of separation membranes. Firstly, the transport mechanisms of gas molecules within membranes are thoroughly analyzed, including the physicochemical foundations of core mechanisms such as Viscous Flow, Knudsen diffusion, surface diffusion, and dissolution-diffusion. Subsequently, based on the separation mechanisms and material structural characteristics, the design strategies and latest advancements in different material systems for gas separation membranes are discussed, with a focus on how microstructure regulates separation performance. Furthermore, the evaluation methods and challenges associated with key performance metrics of gas separation membranes, such as interfacial compatibility, mechanical strength, and long-term stability, are summarized. Finally, to address current bottlenecks in precise interfacial design, multicomponent competitive transport mechanisms, and scalable fabrication, future directions are outlined, emphasizing the use of cross-scale simulations and advanced characterization techniques to reveal underlying physical mechanisms and guide the rational design of next-generation high-performance separation membranes.