Antibacterial activity of cloth functionalized with N-alkylated poly(4-vinylpyridine)

A simple technique was developed to functionalize the surface of commercial cotton cloth with bactericidal polycationic groups. The cloth was first graft copolymerized with 4-vinylpyridine (4VP) and subsequently derivatized with hexylbromide via the quaternization of the grafted pyridine groups into pyridinium groups. X-ray photoelectron spectroscopy (XPS) was used to characterize the cotton cloth after each surface functionalization step. The pyridinium groups introduced on the substrate surface exhibited a high bacterial killing efficiency as shown by airborne and waterborne Escherichia coli (E. coli) assays, as well as a test to measure the number of viable E. coli cells in suspension upon contact with the cloth. This antibacterial property is preserved even after the cloth is subjected to prolonged weathering under UV irradiation and water spray. Wild-type bacteria were also cultured from soil and used to verify the antibacterial potential of the functionalized cloth. The inhibition of biofilm formation on the functionalized cloth was observed even with the inoculation of high concentrations of microorganisms. The success of the present surface functionalization technique as applied to cloth is a promising development, as since cloth is a common material having wide applications.