Room temperature synthesis of Ag/polypyrrole core–shell nanoparticles and hollow composite capsules

Two kinds of Ag/polypyrrole composite nanoparticles have been prepared via a one-step redox reaction between silver nitrate and pyrrole monomer at room temperature. One is Ag@polypyrrole core–shell nanoparticles that were synthesized by making use of synergic inducing effect of polyvinyl pyrrolidone and p-toluenesulfonic acid existing in aqueous solutions. The other is AgCl@Ag/polypyrrole core–shell composite nanoparticles that were synthesized in the presence of HCl using the in situ-formed AgCl particles as the template. For the latter, its core can be easily removed via a simple dissolving procedure in sodium hyposulfite or ammonium chloride aqueous solutions, obtaining the Ag/polypyrrole hollow composite capsules. Experimental results suggest that the shell thickness and core diameter of the resulting composites can be controlled expediently by adjusting reaction time and concentration of pyrrole monomer.