Development of ZnCl₂ Hydrated Molten Salt Solvent and Their Dissolution of Chitin

Chitin, as a natural polymer, was considered to be an ideal functional biomaterial because of its good biocompatibility, abundant storage, and green sustainability. However, the dissolution problems caused by the strong intermolecular and intramolecular hydrogen bonds seriously hindered the development of chitin-based functional materials. A green and feasible ZnCl₂ hydrated molten salt solvent was designed and developed to address the dissolution problem and prepare the chitin-based hydrogels. The results indicated that the zinc chloride molten salt solvent (ZnCl₂·5H₂O ) was characterized by excellent dissolution properties with a high level of solubility (4% mass ratio of chitin to solvent) within 6.0 h at 50 ℃. More importantly, the chitin-based hydrogel could be simply prepared by ethanol regeneration to form functional chitin hydrogels. Meanwhile, based on the existing metal ions, the chitin hydrogel demonstrated good flexibility, ionic conductivity, and freezing resistance, which would show potential apply in flexible wearable devices.