Ag/polypyrrole core-shell nanostructures: Interface polymerization, characterization, and modification by gold nanoparticles

Polypyrrole (PPy)-coated Ag composites were synthesized through an immiscible organic/inorganic biphasic system in the presence of polyvinylpyrrolidone (PVP). Highly dispersed PPy/Ag was obtained by using interface polymerization and controlling the reactive conditions. The presence of PVP could realize the effective coating of PPy on the surface of Ag. The core-shell structure was directly confirmed by transmission electron microscopy and also characterized by techniques such as Fourier transform infrared spectroscopy and X-ray diffraction. Furthermore, three-layered Au-modified PPy-coated Ag nanocomposite was prepared through the reaction of Au colloidal solution and PPy/Ag. Moreover, Au/PPy/Ag nanocomposite was immobilized on the surface of a glassy carbon electrode and applied to construct a dopamine (DA) biosensor. The biosensor exhibited a fast amperometric response to DA with the linear range from 1 x 10(-4) to 5 x 10(-3) mol/L.