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, 2,2-bis(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 gram-positive (Staphylococcus epidermidis) bacteria. The nAg-TiO2 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 nAg-TiO2/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 Ag-TiO2, 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.