Novel two-step synthesis of various gold nanostructures using Langmuir monolayers

Ribbon-like, wedge-shaped, and spherical gold nanostructures were prepared via a novel two-step growth method. Various gold nanostructures were first pre-formed in aqueous solution by using β-cyclodextrin (β-CD) as both reducing and capping agent. Due to the continuous growth of the pre-formed gold nanostructures at the air/water interface with the help of the Langmuir monolayers of 1-hexadecyl-3-methylimidazolium bromide (C16mimBr), morphology changes can be observed obviously. The gold nanostructures were characterized by transmission electron microscopy (TEM) and UV–vis spectroscopy. A possible mechanism based on the interaction between β-CD and the pre-formed gold nanostructures is proposed.