Poly(ethylenimine)-stabilized silver nanoparticles assembled into 2-dimensional arrays at water-toluene interface

A one-pot, size-controlled preparation of amine-functionalized silver nanoparticles is possible using poly(ethylenimine) (PEI) as a reducing and a stabilizing agent simultaneously. The PEI-stabilized Ag nanoparticles thus prepared in aqueous phase can further be assembled into 2-dimensional (2-D) arrays at the water-toluene interface by heating. By the addition of benzenethiol (BT) into the toluene, a more robust 2-D film is formed, not only at the interface but also on the inner surface of the sampling bottle. The latter Ag film can also be formed, through brief contact with the mixture, on glass slides and even on dielectric beads and cotton fabrics. These Ag-coated films are highly surface-enhanced Raman scattering (SERS) active and also exhibit a very intense SERS spectrum of 4-aminobenzenethiol (4-ABT) or 4-nitrobenzenethiol (4-NBT) via a place-exchange reaction that takes place between BT and 4-ABT or 4-NBT. In addition, the Ag-coated fabrics would be used as antibacterial gauzes for the treatment of burned skin and also as antistatic mats for the ready dissipation of electrical energy buildup. The present electroless deposition method of Ag is thus expected to serve as a technique in high demand in various fields.