Cucurbituril - Based Supramolecular Polymer Gels: From Macrocycle Synthesis to Functional Composite Networks

Cucurbiturils (CB[n]) are rigid glycoluril-based macrocyclic hosts with defined cavities that form high-affinity host–guest complexes in aqueous solutions. This review examines cucurbituril-based supramolecular polymer gels as functional composite materials, integrating synthetic chemistry with materials science perspectives. We systematically cover (1) the synthesis and functionalization of cucurbiturils tailored for gel applications, including classical acid-catalyzed condensation and modern green methodologies; (2) fundamental design principles for incorporating CB[n] as dynamic crosslinkers in polymer networks; (3) structure–property relationships governing mechanical behavior, self-healing capacity, and stimuli-responsiveness; and (4) contemporary applications in biomedical engineering, soft electronics, and environmental remediation. Emphasis is placed on how molecular-scale host–guest interactions translate to macroscopic composite properties. The review concludes with perspectives on scalable synthesis, processing integration, and future directions in supramolecular composite materials.