Preparation and Multi-functional Properties of Flexible Chitosan/Hydrolyzed Wool Keratin/Graphene Composite films

Flexible chitosan/hydrolyzed wool keratin/graphene (Cs/HWK/Gr) composite film with multi-functionalities was prepared by the assistance dispersion effect of hydrolyzed wool keratin (HWK). With the growing emphasis on environmental protection, bio-based materials have garnered increasing attention. Wool keratin, a promising bio-based material, has recently been discovered to effectively disperse graphene (Gr) in aqueous solutions. In this study, we utilized HWK to achieve uniform dispersion of Gr. Subsequently, leveraging the film-forming properties of chitosan (Cs), Cs/HWK/Gr composite films was fabricated. When the mass ratio of HWK to Gr was 16:6, the Cs/HWK/Gr film exhibits uniformity, flexibility and conductive properties. Its electrical conductivity ranges from 1 to 27   S/m when the ambient humidity was below 33%. They can be employed as strain sensors to monitor the bending activities of wrists and fingers. Additionally, the thermal management performance of Cs/HWK/Gr composite film was evaluated. It indicated that the Cs/HWK/Gr composite film possesses very high absorptivity in the 250~2500   nm, showcasing a significant photothermal effect. The composite films also exhibited superior electrical heating properties, increasing temperature by 51.5℃ under 15   V DC voltage. Furthermore, the Cs/HWK/Gr composite films exhibited excellent antibacterial properties, with an inhibition rate of 99% for Escherichia coli and 98% for Staphylococcus aureus. This research provides a feasible method to prepare bio-based multifunctional film which has potential applications in the fields of sensing and clothing materials.