Long-lasting renewable antibacterial graphene/N-halamine-coated cotton fabrics benefitting from enhanced UV stability and quantitative tracking of bactericidal factors

In this study, anionic GO aqueous dispersion and cationic QAS aqueous solution with specific concentrations were applied for the fabrication of modified cotton fabrics (MCFs) through the layer-by-layer self-assembly method. The chlorinated cotton fabrics with optimized protocol possessed excellent ultraviolet-blocking properties, with a UPF value of 323.08. Moreover, graphene greatly improved the UV stability of N-halamine, which could also be proved in the UV aging test of MCFs. In addition, the modification procedure also endowed cotton fabrics with superhydrophobic properties, thus broadening the application range of cotton fabric. The obtained GQC10 possessed excellent antibacterial activity, with all inoculated S. aureus and E. coli O157:H7 being completely killed within 5 min and 1 min of contact time, respectively. Indicated by the quantitative function relation between the active chlorine content (ACC) and the surface sheet resistance (SSR) of the MCFs, a novel and simple method for the determination of ACC was established. This method could be used to monitor the antimicrobial efficacy to ensure its sustainability. Furthermore, according to the variation frequency of SSR, the risk level of bacterial hazards in different places could be evaluated, thus broadening the application range of N-halamine-based antibacterial cotton fabrics.