Nanocomposite thin films containing Pd nanoparticles were formed by alternating adsorption of poly(allylamine hydrochloride) and using a layer-by-layer self-assembly technique and subsequent postdeposition reduction of the ions by sodium borohydride (NaBH4). The composition, structure, and properties of the composite films were characterized by ultraviolet-visible spectroscopy (UV-Vis), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). FESEM images indicate that the composite film has a rough surface and the size of Pd nanoparticles is in the range of 50～100 nm. The UV-Vis characteristic absorbances of PAH and Pd increase almost linearly with the number of bilayers, which suggests that the deposition process be regular and highly reproducible from layer to layer. XPS result confirms the formation of Pd nanoparticles in the films. The multilayer films exhibit good electrocatalytic activity for the oxidation of uric acid, which may be used in electrochemical biosensors in future.

Key words: poly(allylamine hydrochloride)/Pd nanocomposite thin film, layer-by-layer self-assembly, multilayer film