The Diels-Alder reaction, a classical (4+2) cycloaddition process, holds significant standing within the realms of organic synthesis and polymer chemistry, frequently employed in areas such as pharmaceutical production and material science. Recently, hydrogels constructed via Diels-Alder reactions have garnered considerable attention from researchers. This review aims to summarize the advancements in utilizing the Diels-Alder reaction for hydrogel synthesis, exploring its impact on structural design, functionalization, and application domains. Initially, the fundamental principles of the Diels-Alder reaction are introduced alongside an examination of its benefits and characteristics in hydrogel fabrication. Subsequently, applications of Diels-Alder-generated hydrogels in biomedicine, smart responsive materials, drug delivery systems, among other fields, are comprehensively reviewed. Challenges and limitations encountered during hydrogel synthesis using this reaction are also discussed. Finally, prospective research directions and future prospects of Diels-Alder reactions in hydrogel synthesis are contemplated.
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