Metallic nanoparticles from single polyelectrolyte molecules

Here we report on the metallization of poly(2-vinylpyridine) (P2VP) by coordination with palladium acetate (PA) followed by reduction with dimethylamine borane (DAB) to metallic palladium. The morphology of the resulting products deposited on a flat surface was analyzed with AFM. If P2VP, PA and DAB are mixed together, the Pd clusters up to 30 nm in diameter are obtained. A two step synthetic procedure was examined. The initially prepared complex P2VPH-1/2(PdCl4) Was deposited on Si-wafer and then reduced, leading to the Pd clusters with a narrow size distribution (3 nm height by 100 run length). Alternately, a step-by-step procedure was used wherein P2VP single molecules were deposited on Si wafers from very dilute acidic aqueous solutions then placed in PA solution and finally reduced with DAB, resulting in the 1.55 nm in the diameter wire-shaped Pd nanoparticles with the length of about 350 nm.