Synthesis of Silver Nanoparticles in Cotton Fabric by Polyvinyl-2-pyrrolidone as a Reducing and Stabilizing Agent

Silver nanoparticles have been extensively applied in various fields such as polymers and textile fibers considering their well known antimicrobial properties. In conventional methods nano silver is synthesized through chemical reduction however، in this paper a novel synthesis method based on aqueous solution of ammonia/silver complex with cationic stabilizer along with UV-C irradiation is introduced. On this basis، silver nitrate was oxidized with sodium hydroxide and then transformed into [Ag (NH3) 2]+ aqueous solution with ammonia followed by adding PVP as a reducing and stabilizing agent and irradiated by UV-C. The formation of silver nanoparticles was confirmed from the appearance of surface plasmon absorption and the X-ray diffraction (XRD) demonstrated that the colloidal nanoparticles were pure silver and Zeta sizer showed particle size distribution. Cotton fabric finishing was accomplished in pad process with various concentrations of nano-sized colloidal silver. Some characteristics of the fabric such as antimicrobial against different microorganisms including gram positive bacteria (Staphylococcous aureus)، one gram negative bacteria (Escherichia coli)، UV–vis spectrophotometry، color space a*، b* and L*، scanning electron microscopy، EDAX were investigated. Very good antibacterial efficacy against S. aureus and E. coli (higher than 97%) appeared even by applying a low nanosilver content (200 ppm) for twenty cycles of home laundering. Polyvinyl pyrrolidone resulted in a remarkable control in the release of silver nanoparticle from the coating and can improve the long-term microbiological activity، especially against home laundering.