Synthesis of gold nanostructures using Langmuir monolayers of ionic liquid-type Gemini imidazolium surfactants

Abstract

Gold nanostructures are successfully synthesised under Langmuir monolayers of ionic liquid-type Gemini imidazolium surfactants [Cnim-4-Cnim][Br2] (n=10, 16) through interfacial reduction of AuCl4− by formaldehyde gas. The Au nanostructures are characterised using transmission electron microscopy and UV–vis spectroscopy. It is found that the concentration of HAuCl4 aqueous solution, the surface pressure and the length of the hydrophobic chains of the surfactants strongly influence the formation of Au nanostructures. A potential mechanism of such diverse morphologies is also discussed.