Self-healing films based on chitosan containing citric acid/choline chloride deep eutectic solvent

Plasticized chitosan films with high content (67-82 wt%) of natural deep eutectic solvent (NADES) based on citric acid and choline chloride were prepared by solution casting method. The thickness of films was 19 +/- 3 mu m. The self-healing and water vapor bending movement of prepared films were demonstrated. Maximal mechanical characteristics of 84% elongation at break and 18 MPa strength, were achieved for a film containing 67 wt% of NADES. The formation of hydrogen bond network in the chitosan film due to replacement of citric acid with NADES (citric acid/choline chloride) was observed with FTIR. It is proposed that this network is responsible for self-healing ability of the chitosan-citric acid-choline chloride films. Structure, morphology and thermal properties of the prepared films are also discussed.

Automated summary

Plasticized chitosan films with high content of NADES based on citric acid and choline chloride were prepared, showing self-healing ability and maximal mechanical characteristics. The formation of hydrogen bond network in the films was observed, suggesting its role in self-healing capabilities. Structure, morphology, and thermal properties of the prepared films were discussed.