Synthesis, formation mechanism and surface-enhanced Raman scattering properties of silver tangled nanowires and dendritic structures

Abstract

Silver tangled nanowires and dendritic structures were readily synthesized in high yield by reducing silver nitrate with different concentrations of ascorbic acid in a polyacrylamide (PAM) aqueous solution at mild conditions (normal temperature and pressure). The structures obtained all have tangled morphology, which is different from the silver nanowires reported previously. The structures of the obtained sliver structures were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, and UV-Vis spectroscopy. PAM plays a key role in the formation of these anisotropic nanostructures as the capping agent and as a soft template. During the initial stage, silver nuclei are formed and PAM molecules simultaneously adsorb on their surfaces. Then, small silver particles will collide with each other along the polymer chains leading to the formation of tangled structures. Additionally, a too high concentration of ascorbic acid is unfavorable for the growth of tangled silver nanowires, and dendritic structures are formed. The surface-enhanced Raman scattering (SERS) activity was investigated using p-aminothiophenol (PATP) as a probe molecule. The silver tangled nano wires and dendritic structures show efficient surface enhanced Raman scattering property. © Editorial office of Acta Physico-Chimica Sinica.