Assembly of Metal Nanoparticles on Electrospun Nylon 6 Nanofibers by Control of Interfacial Hydrogen-Bonding Interactions

Assembly of metal nanoparticles (Ag, Au, Pt) onto nylon 6 nanofibers by controlling the interfacial hydrogen-bonding interactions has been demonstrated. Metal nanoparticles were synthesized in aqueous media using sodium citrate as a stabilizer. Nylon 6 nanofiber mats, produced by electrospinning, were immersed into pH-adjusted solutions of metal nanoparticles. The key factor determining the assembly phenomena was identified as the hydrogen-bonding interactions between the amide groups in the nylon 6 backbone and the carboxylic acid groups capped on the surface of the metal nanoparticles. The assembly was strongly dependent on the pH of the media, which affected the protonation of the carboxylate ions on the metal nanoparticles, hence influencing the hydrogen-bonding interactions between nanofibers and nanoparticles. High Surface coverage of the nanofibers by the Ag nanoparticles was found at pH intervals from 3 to 6, whereas only a few Ag nanoparticles were found on the surface of the fibers when the pH was greater than 7. The nylon 6 nanofiber mats decorated with Ag nanoparticles exhibited strong antibacterial activity against Escherichia coli.