Antibacterial textiles prepared by RF-plasma and vacuum-UV mediated deposition of silver
The bacterial inactivation efficiencies of silver metal and oxides and their combinations on textile fabrics was investigated to evaluate the disinfectant action on airborne bacteria. The inactivation performance was seen to depend on the amount of silver on the textile surface. The preparation of the polyester-polyamide Ag-loaded textiles was carried out by RF-plasma and vacuum-UV (V-UV) surface activation followed by chemical reduction of silver salts. The rate of bacterial inactivation by the silver loaded textile was tested on Escherichia coli K-12 and showed long lasting residual effect. Specular reflectance has been employed to assess the optical properties of the Ag-loaded fabrics. By elemental analysis it was found that levels of Ag loading >0.118% (w/w) for the vacuum-UV samples lead to complete inhibition of bacterial growth. X-ray photoelectron spectroscopy (XPS) shows that for textiles activated by RF or V-UV methods, the silver in the topmost layer increases with increasing concentration of the Ag used in the precursor solution. The exact determination of the oxidation state of the Ag-clusters on the textile is difficult because of the variation of particle size and electrostatic charging of the supported particles. Ag metal was found to be the main component of the Ag-clusters and not Ag2O and AgO as identified by the binding peak energies (BE). By transmission electron spectroscopy (TEM) it was seen that the Ag-clusters were deposited on the two polymer components of the textile fabric but having widely different sizes. (C) 2003 Elsevier Science B.V. All rights reserved.