Synthesis, characterization and antimicrobial activity of colloidal copper nanoparticles stabilized by cationic thiol polyurethane surfactants

Metal nanoparticles have attracted considerable interest particularly because of the size dependence of physical and chemical properties and its enormous technological potential. Among different metal nanoparticles, copper nanoparticles have attracted great attention because copper is one of the most key metals in new technology. Chemical methods are used to synthesize copper nanoparticles. Chemical reduction is the most frequently applied method for the preparation of stable, colloidal dispersions in organic solvents. In this paper, the new cationic thiol polyurethane surfactants with different alkyl chain length were synthesized (PQ10, PQ14 and PQ18). The chemical structure of the synthesized surfactants was confirmed using infra-red spectroscopy (IR) and proton nuclear magnetic resonance spectroscopy (¹HNMR). Copper nanoparticles colloidal solution of 40–80 nm diameters was prepared using sodium borohydride in aqueous solution at room temperature as reducing agent. The synthesized surfactants decrease the aggreegation of copper nanoparticles. The nanostructure of the synthesized surfactant with copper nanoparticles with diameters ranging from 31.5 to 10.3 nm was prepared and characterized using ultra violet spectrophotometer (UV), infra-red spectroscopy (IR) and transmission electron microscope (TEM). The results declare formation and stabilization of copper nanoparticle using synthesized cationic surfactants. Antimicrobial activity of the synthesized cationic surfactants and their nanostructure with copper nanoparticles were evaluated against pathogenic bacteria and fungi.