Controlled synthesis of gold nanorings with structural defects assisted by elastic induction of mixed surfactants

Abstract

Controlled synthesis of gold nanorings was realized by reducing chloroauric acid in aqueous mixed solutions of cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS). It is revealed that the gold nanowires are induced to fabricate the gold nanorings with an average diameter of ~300 nm. The synthesis of the nanowires and the formation of the nanorings can be achieved in one step. A variety of gold nanostructures, such as short nanowires, nanorings, nanostars with a number of soft protuberances and nanopolyhedra, could be readily obtained by simply changing the CTAB/SDS molar ratio. Both the “structural defects” and the “elastic induction”, which are closely related to the mixed bilayers (CTAB/SDS), are indispensable for the final formation of the gold nanorings. Four surfactants with similar structures were also used to further verify the formation mechanism.