Facile preparation of surface N-halamine chitin nanofiber to endow antibacterial and antifungal activities

N-halamine chitin nanofiber (NF) film was prepared by the reaction of chitin NF film with sodium hypochlorite solution to endow the film with antibacterial and antifungal activities. The amount of active chlorine content loaded on the chitin NF film depended on the sodium hypochlorite concentration and reaction time. FT-IR, UV-vis, XRD, and TG analyses showed that the NH bond was substituted to the NCl bond and that the reaction took place at the chitin NF surface. After chlorination, the characteristic nanochitin morphology was maintained. Although the active chlorine content of the film gradually decreased by disassociation of the NCl bond, chlorine was rechargeable into chitin NF by another sodium hypochlorite solution treatment. The chlorinated chitin NF film showed strong efficacies against Gram-negative and -positive bacteria of Escherichia coli and Staphylococcus aureus, respectively. Moreover, the films showed 100% and 80% inhibition of spore germination when faced against Alternaria alternata and Penicillium digitatum fungi, respectively.