Porous organic cage separation membranes: Exploratory journey from preparation to application

Porous organic cages (POCs) represent a novel class of low-density crystalline materials that exhibit distinctive pores comparable to those observed in three-dimensional extended network materials, including metal organic frameworks (MOFs), covalent organic frameworks (COFs), and porous organic polymers (POPs). Owing to their adjustable pore sizes, high specific surface areas, and discrete molecular structures, POCs exhibit excellent solution dispersibility and processability, thereby providing a broad spectrum of potential strategies for the design and fabrication of POC separation membranes. This review presents a comprehensive and systematic summary of the recent research progress in the preparation techniques and applications of POC separation membranes. We summarize a comprehensive overview of preparation strategies for POC separation membranes, including physical blending, spin coating, and interfacial polymerization, and analyze their advantages and limitations. Recent developments in the separation applications of POC separation membranes are highlighted, such as gas separation, ion separation and molecular separation, as well as current challenges and future development trends in this field, are briefly discussed. We anticipate that this review will offer a pertinent perspective to promote advancements in the development of advanced POC separation membranes, and be useful to researchers in related fields.