Silver-Doped TiO2/Polyurethane Nanocomposites for Antibacterial Textile Coating

Silver-doped titania/polyurethane (nAg-TiO2/PU) nanocomposite coatings were synthesized through a combined solution combustion and grafting from polymerization method, where nanosilver-doped titania (nAg-TiO2) was chemically attached to the skeleton of the polyurethane polymer matrix with a bifunctional monomer, 2,2bis( hydroxymethyl) propionic acid (DMPA). The polyester fabric functionalized with nAg-TiO2/polyurethane composites using dip-coating method has shown excellent antibacterial activity against gram-negative (Escherichia coli) and grampositive (Staphylococcus epidermidis) bacteria. The nAgTiO(2) photoreduced under methanol vapor exhibited an improved bactericidal activity because of the formation of elemental silver instead of silver oxide. XRD-EDX analysis was conducted to elucidate the percent of silver doping, the crystalline structure of titania, and the coating pattern of nAgTiO(2)/ PU over polyester fabric. One percent silver-doped titania was considered optimum because of its higher bactericidal activity when compared with higher-percent silver-doped titania. Effective bactericidal activity has been observed under the black light illumination, which, in conjunction with AgTiO2, completely inhibits any bacterial growth within 3 h of exposure. Antimicrobial effect of coating of nAg-TiO2/PU on polyester fabric was retained even after 30 traditional textile washings.