Antibacterial behaviour of quaternized poly(vinyl chloride)-g-poly(4-vinyl pyridine) graft copolymers

Amphiphilic graft copolymers consisting of poly(vinyl chloride) (PVC) main chains and poly(4-vinyl pyridine) (P4VP) side chains were synthesized via atom transfer radical polymerization (ATRP) using direct initiation of chlorine atoms. The successful synthesis of PVC-g-P4VP graft copolymers was confirmed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR). Transmission electron microscope (TEM) and small angle X-ray scattering (SAXS) analysis showed that PVC-g-P4VP exhibited microphase-separated, ordered structure with 37.6 nm of domain spacing, which was not observed in neat PVC. For antibacterial applications, the tertiary nitrogen atoms of PVC-g-P4VP was quaternized using 1-bromohexane, as confirmed by FTIR measurements. Bacteria including Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Bacillus cereus (B. cereus), and Pseudomonas aeruginosa (P. aeruginosa) were completely killed in 24 h on the quaternized PVC-g-P4VP (46% grafting) surface, indicating its excellent antibacterial behavior while it showed to be cytotoxic to mammalian cell.