Antimicrobial coating of modified chitosan onto cotton fabrics

•Cyclic N-halamine-based chitosan was synthesized.•The synthesized N-halamine-based chitosan was characterized by NMR, FT-IR, and SEM.•The synthesized chitosan derivative (chitosan-HDH) was coated onto cotton fabrics.•Cotton fabrics coated with the N-halamine-based chitosan showed excellent efficacies against bacteria. Chitosan has been applied as an antibacterial agent to provide biocidal function for textiles but has limitations of application condition and durability. In this study, a new N-halamine chitosan derivative was synthesized by introducing N-halamine hydantoin precursor. The synthesized chitosan derivative 1-Hydroxymethyl-5,5-dimethylhydantoin chitosan (chitosan-HDH) was coated onto cotton fabric with 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. The coatings were characterized and confirmed by FT-IR and SEM. The treated cotton fabrics can be rendered excellent antimicrobial activity upon exposure to dilute household bleach. The chlorinated coated swatches can inactivate 100% of the Staphylococcus aureus and E. coli O157:H7 with a contact time of 5min. Almost all the lost chlorine after a month of storage could be recharged upon rechlorination. The crease recovery property of the treated swatches improved while the breaking strength decreased compared with uncoated cotton.