Self-healable hydrogels with NaHCO3 degradability and a reversible gel-sol-gel transition from phenolic ester containing polymers

Due to their fantastic self-healing property, similar to that of organisms, self-healable hydrogels have attracted considerable attention in recent years. Herein, self-healable hydrogels with degradability in NaHCO3 were prepared and showed a reversible gel-sol-gel transition under a variety triggers. The hydrogel was prepared from poly(N, N-dimethylacrylamide-stat-4-formylphenyl acrylate), P( DMA-statFPA), and dihydrazide with dynamic acylhydrazone and disulfide cross-linking. With base labile phenolic ester bond connections, the hydrogel can be degraded by the extremely mild base, NaHCO3 solution. With a dihydrazide compound as a cross-linker, the hydrogel formed and self-healed without any additional catalysis or stimulus. Moreover, the self-healable hydrogels showed a reversible gel-sol-gel transition under various conditions, including pH, redox and group ratios, based on the reversible characteristics of acylhydrazone and disulfide bonds. With these superior properties, the developed hydrogel holds great potential for applications in many biomedical fields, including tissue engineering, drug delivery carriers and biosensors.