Cross-linking induced thermo-responsive self-healing hydrogel with gel-sol–gel transition constructed on dynamic covalent bond

Based on the favorable biocompatibility, thermo-responsive hydrogels have attracted much attention. Therefore, more and more researchers have focused on the synthesis, characterizations and applications of thermo-responsive hydrogels.In this study, copolymer of P(N-hydroxymethyl acrylamide-co-diacetone acrylamide) P(NAM-co-DAA) with ketone groups were prepared to construct the thermo-responsive hydrogel through cross-linking induced thermo-response (CIT). The dihydrazide compounds were employed to cross-link the copolymer to make a self-healing hydrogel which containing ketone type reversible acylhydrazone bond. The resultant self-healing hydrogel has shown the excellent mechanical properties and chemical stabilities. At the same time, the hydrogel presented reversible gel-sol based on the pH value and group ratio. These thermo-responsive self-healing hydrogels also demonstrate wonderful biocompatibility, which extends its potential applications as biomaterials.