Self-healing, stretchable, and freezing-resistant hydroxypropyl starch-based double-network hydrogels

Starch hydrogel is a biocompatible and biodegradable material. However, due to its poor mechanical properties and fragility, starch hydrogel has limited applications in the food and medicine industries. In this work, we prepared stretchable, compressible, and self-healing double-network (DN) hydrogels using hydroxypropyl starch (HPS) and sodium alginate (SA). By adjusting the amount of sodium alginate added, the DN hydrogels achieved adjustable mechanical properties. The storage modulus of the DN hydrogels with 1% SA increased by nearly 80 times compared with that of pure HPS hydrogels. When prepared in a water/glycerol binary mixed solvent, the DN hydrogels can maintain their gel properties at -30 ºC. These environmentally friendly and biocompatible hydrogels have broad application prospects in the fields of agriculture, food, and medicine.