Ramified gold deposits at the gas ∣ liquid interface

Ramified gold films have been prepared by electroless deposition at the surface of aqueous mixtures of hydrogen tetrachloroaurate and potassium chloride, covered by a positively charged dimethyldioctadecylammonium monolayer. We show that increasing the concentration of chloride anions in the subphase induces a progressive modification of the morphology of the gold deposits, from compact to finely ramified patterns. Both the nature of the dissolving electrode and the presence of the positively charged surfactant monolayer have a profound effect on the structure and the growth mechanism of such ramified deposits.