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

Abstract

ABSTRACTChitosan‐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.