Supramolecular Hydrogel of Chitosan in the Presence of Graphene Oxide Nanosheets as 2D Cross-Linkers

Biomass-based materials are attractive due to their renewability, biodegradability, and biocompatibility. Chitosan is a typical biomacromolecule that can be used as feedstock for novel materials. Here, the self-assembly of chitosan chains with graphene oxide (GO) nanosheets has been studied, where GO works as the two-dimensional crosslinker dues to its multifunctional groups on both sides. Supramolecular hydrogels of chitosan. and GO have been prepared by controlling the concentration of GO, ratio of chitosan to GO, and temperature. It was found that at high GO concentration, hydrogel can be obtained at room temperature, and the as-prepared hydrogel showed a self-healing performance. However, at low GO concentration, the supramolecular hydrogel formed only at high temperature (95 C). The driving force for the hydrogel is believed to be the noncovalent interactions. The reversible hydrogels have potential applications in fields of biomaterials, wastewater treatment, and smart materials.