The formation and performance tuning mechanism of starch-based hydrogels

Starch-based hydrogels, characterized by their three-dimensional network structures, are increasingly explored for their biodegradability, low cost, and abundance of modifiable hydroxyl groups. However, a comprehensive understanding of the mechanisms behind the formation and property modulation of these hydrogels has not been systematically described. Drawing from literature of the past decade, this review provides insights into designing multifunctional starch-based hydrogels through various gelation mechanism, crosslinking strategies, and second-network structure. This comprehensive review aims to establish a theoretical framework for controlling the properties of starch-based hydrogels. A crucial aspect of starch hydrogel formation is the dense, cellular structure produced by swollen particles; when these particles fully disrupt, amylose recrystallization creates "junction zones" essential for network stability. In double-network hydrogels, materials such as polyvinyl alcohol (PVA), sodium alginate (SA), and polyacrylamide (PAM) form an effective secondary network, enhancing the mechanical strength and versatility of the hydrogel. The functionalization of starch-based hydrogels is primarily achieved through the introduction of functional group, secondary networks, and ionic liquids.