Self-Healing Polysaccharide Hydrogel Based on Dynamic Covalent Enamine Bonds

A self-healing polysaccharide hydrogel based on dynamic covalent enamine bonds has been prepared with a facile, cost-effective, and eco-friendly way. The polysaccharide hydrogel is obtained by mixing cellulose acetoacetate (CAA) aqueous solution with chitosan aqueous solution under room temperature. CAA is synthesized by reaction of cellulose with tert-butyl acetoacetate (t-BAA) in ionic liquid 1-allyl-3-methylimidazolium chloride (AMIMCl). The structure and properties of CAA are characterized by FT-IR, NMR, and solubility measurements. The results demonstrate that CAA possesses water solubility with a degree of substitution (DS) about 0.58-1.11. The hydrogel shows an excellent self-healing behavior without other external stimuli and good stability under physiological conditions. Furthermore, the polysaccharide hydrogel exhibits pH responsive properties.