Stable N-halamine on polydopamine coating for high antimicrobial efficiency

Abstract

In this paper, we report a simple method for preparing a highly effective antibacterial coating by the introduction of an N-halamine structure on a polydopamine (PDA)-based coating. The PDA-based coating includes only PDA and PDA co-deposited with polyethylenimine (PEI). The amine groups in PDA and PEI are assumed to be chlorinated and converted to N-halamine. After the simple immersion of PDA-based coatings in a dilute bleach solution, the formation of N-halamine is confirmed by iodometric titration. Compared with the original PDA-based coating, N-halamine-functionalized PDA-based coatings exhibit high antibacterial activity toward Gram-positive S. aureus and Gram-negative E. coli within a brief contact time. Notably, the PDA samples retain their oxidative chlorine content after extended storage, and ~90% of the chlorine is restorable after repeated quenching. The coatings are applicable to a wide spectrum of substrates and are stable. This study may provide a simple, effective method for the preparation of functional fibers with antibacterial activities for the clothing and textile industries.