The possibility to make a deposit by the electrochemical way is used in the industry notably in the processes of metallic coating. This method of reducing the ions is known from a long time. It always appears as a promising tool for the synthesis of new micro- or nano-materials, with a controlled structure and morphology. In this context, we studied the growth of gold films at the gas/liquid interface of an aqueous tetrachloroaurate (AuCl4-) solution. These metallic deposits are obtained by confining the electrodeposition or electroless process in this area of the solution, thanks to electrostatic interactions between the metallic anions in solution and a monomolecular film of a positively charged surfactant (the dimethyldioctadecylammonium). The study of the electrochemical process revealed the existence of two reducing potentials of the metallic ions. The one associated with the two-dimensional growth of the gold film is directly linked to the presence of the monolayer. Then, we showed that it is possible to control the growth mode of the gold films between two-dimensional and three-dimensional deposition. More over, the electroless deposition allows us to show the role of different parameters. For example, the addition of greater and greater quantities of chloride ions in the solution enables the formation of deposits with a greater and greater indented aspect.
Electrochemical growth of gold at the gas/liquid interface