The interconversion between gold nanostars and gold nanodendrites controlled via temperature and the concentration of sodium dodecyl sulfonate

Abstract

Gold nanostars and gold nanodendrites were readily synthesized by the reduction of HAuCl4 with ascorbic acid in aqueous mixed solutions of the cationic surfactant decane-1,10-bis(methylpyrrolidinium bromide) ([mpy-C10-mpy]Br2) and the anionic surfactant sodium dodecyl sulfonate (SDS). The interconversion of morphologies between gold nanostars and gold nanodendrites can be achieved by changing the reaction temperature under the otherwise identical conditions, which is seldom reported. Due to the electrostatic interaction, the introduction of SDS brought the dramatic impact to the formation process and the final morphologies of the gold nanostructures. Both of the hierarchical structures were found to yield large surface-enhanced Raman scattering (SERS) enhancement factors for rhodamine 6G (R6G) and the aspect ratio is a key factor for the enhancement.