Salicyl-imine-chitosan hydrogels: Supramolecular architecturing as a crosslinking method toward multifunctional hydrogels

Hydrogels based on chitosan and salicyladehyde were obtained by dynamic covalent chemistry. The unusual chitosan gelling in the presence of the monoaldehyde has been deciphered following and correlating data of NMR, FTIR, single crystal and wide angle XRD, POM and optical measurements. Of significant importance in understanding the crosslinking features was the synthesis of a model compound and the successfully growth as single crystal allowing the study of its supramolecular peculiarities. The hydrogels exhibited in SEM a porous or fibrous morphology, in good correlation with the crosslinking degree. They swelled very fast, similar to the superporous hydrogels of third generation and exhibited self-healing properties. Rheological investigation demonstrated good mechanical properties, thermosensitivity and thixotropy. The paper revealed a hydrogel with suitable properties for use in bio-medical applications, and moreover, revealed a new concept of obtaining chitosan hydrogels using monoaldehydes − which are widespread in nature, cheap and beneficial to the human body.