Long-term stabilization of mixed silver nanoparticles on an Al surface with poly(2-vinylpyridine) films

Surface-enhanced Raman scattering active substrates were prepared by the chemical assembly of Co, Ni and Ag nanoparticles on 3-aminopropyltriethoxysilane-functionalized Al surface. Poly(2-vinylpyridine) films were also deposited on the Al substrates by electrochemical polymerization in aqueous solution. Raman intensities were measured with respect to pyridine. Although silver has very desirable physical properties, good relative abundance, and low cost, gold nanoparticles have been widely favored because of their proved stability and ease of use. Unlike gold, silver is notorious for its susceptibility to oxidation (tarnishing), which has limited the development of important silver-based nanomaterials. However, the substrates with poly(2-vinylpyridine) films were exceptionally stable as they produced spectra that did not change even after much more than one year.