Catalytic Nanoparticles Formed by Reduction of Metal Ions in Multilayered Polyelectrolyte Films

Alternating adsorption of polyethyleneimine−metal ion complexes and polyanions results in the formation of multilayered polyelectrolyte films. Postdeposition reduction of the metal ions by heating or exposure to NaBH4 then yields composite films containing metal nanoparticles. UV/visible spectroscopy and transmission electron microscopy confirm the formation of well-dispersed nanoparticles with sizes (4−30 nm) that depend on the concentration of metal ions initially in the film. These films are effective as both catalysts and antimicrobial coatings.