Chitosan-based double network hydrogels with self-healing and dual-responsive shape memory abilities

Chitosan-based single network hydrogels with imine bonds have excellent self-healing capability, while poor mechanical properties limit their applications. Here, chitosan-polyacrylamide-based double network hydrogels were prepared via in situ free-radical polymerization of acrylamide in the presence of N -carboxyethyl chitosan (CEC) and dibenzaldehyde-terminated telechelic poly(ethylene glycol), which had excellent mechanical properties, self-healing, and dual-responsive shape memory abilities. The maximum tensile strength and elongation at break could reach 460 kPa and 4600%, respectively. Meanwhile, owing to the reversibility of imine bonds, elongation and strength at break of hydrogels could heal by 84.2 and 93.2% under alkali stimulation at 35 °C, respectively. Furthermore, the hydrogels also had good shape memory abilities for pH-stimuli responsiveness of the imine bonds and metal ions stimuli responsiveness of CEC. The prepared chitosan-based functional hydrogels have great potential application prospects in tissue scaffolds, actuators, and wearable devices. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48247.