Search

N-Halamines, commonly known as hydantoins, are being increasingly explored for generating antibacterial surfaces. The synthesis of hydantoin-based polymers usually involves the conjugation of polymerizable moieties at the imide position of 5,5′-disubstituted hydantoin, thereby restricting the halogen capture only at the amide nitrogen. In this study, we report the synthesis of a new hydantoin monomer that possesses both amide and imide nitrogens for improved halogen capture and enhanced antibacterial activity. Moreover, unlike previous reports, the synthesized monomer lacks the vicinal C–H group next to N–Cl in the hydantoin ring, preventing HCl elimination upon chlorination and enhancing its antibacterial efficacy, durability and rechargeability. Copolymers of the hydantoin monomer with methyl methacrylate (MMA) and styrene were synthesized and characterized using NMR, HRMS, FTIR, XPS, TGA, DSC and GPC. Polymers containing oxidative chlorine contents varying from 0.85% to 1.35% were employed to modify the glass surface through spin coating. The copolymer coated surfaces exhibited total kill (6 log reduction) of bacteria such as S. aureus and E. coli in 13 min and 15 min, respectively.

N-Halamine-based antibacterial polymers play a significant role in controlling microbe-associated surface contamination. Hydantoin-containing polymers are usually synthesized by tethering polymerizable moieties to 5,5′-dialkyl hydantoin. However, such approaches sacrifice the imide hydrogen in the molecule, thereby restricting the halogen capture only to the amide nitrogen. In this paper, we report the synthesis of a novel polymerizable hydantoin monomer containing one more amide group in addition to the amide and imide groups already present in hydantoin to maximize the halogen capture and hence its antibacterial activity. The synthesized monomer was copolymerized with methyl methacrylate (MMA) and styrene. The monomer and its copolymers were characterized using 1H and 13C NMR, HRMS, FTIR, XPS, TGA, DTA and GPC. The oxidative chlorine content of the copolymers ranged from 0.9% to 1.21%. The polymers were spin coated onto glass surfaces to study their antimicrobial potential. The polymer-coated glass surfaces exposed to both Gram positive S. aureus and Gram negative E. coli bacteria using standard protocols showed total kill of the bacteria within 15 minutes of exposure. These new hydantoin polymers showed highly superior antibacterial activities compared to many such polymers reported so far in the literature.