Tunable thermosensitive behavior of multiple responsive chitin

Chitin can be dissolved and homogeneously functionalized in NaOH/urea aqueous solvent. Previously, we reported that chitin modified with acrylamide (AMC) possesses high water solubility and can undergo a sol-gel transition responding to pH and cationic ions. In this report, we further explored the thermosensitive behavior of this multiple responsive chitin. We showed that the sol-gel transition temperature of AMC can be facilely adjusted by the degree of substitution (DS), pH, polymer concentration and the presence of anions or cations. Importantly, AMC can form a hydrogel at 37 °C and return to solution at 4 °C by adjusting experimental parameters. We anticipate this multiple responsive chitin may have potential applications in injectable materials and smart drug delivery.