Dual antibacterial effect of immobilized quaternary ammonium and aliphatic groups on PVC
A coating comprising quaternary ammonium salts (QAS) and aliphatic moieties was formed on the poly(vinyl chloride) (PVC) surface in order to confer antibacterial activity. This was achieved by grafting mercaptopropyltrimethoxysilane onto PVC, followed by aminopropyltriethoxysilane. Betaine and dodecenyl succinic anhydride (DDSA) were bonded to free amine groups. The modified PVC samples were characterized by FT-IR, showing that the PVC surface was successfully coated. Energy dispersive X-ray spectroscopy showed the spatial distributions of the elements Si and S, indicating that the coatings were homogeneous. Betaine and DDSA coated PVC showed a better antibacterial performance than the controls. This antibacterial effect was extremely reinforced in betaine–DDSA modified PVC showing greater antibacterial activity than both treatments separately applied. Antibacterial activity against Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis was studied in the treated samples showing that the coating was effective against Gram positive and Gram negative species.