Evaluation on corrosively dissolved gold induced by alkanethiol monolayer with atomic absorption spectroscopy

Abstract

We have monitored a gold corrosive dissolution behavior accompanied in n-alkanethiol like n-dodecanethiol assembled process with in situ quartz crystal microbalance (QCM), and then observed it with atomic force microscopy (AFM) which showed an evident image of corrosive defects or holes produced on gold substrate, corresponding to gold dissolution induced by the alkanethiol molecules in the presence of oxygen. For detection of the dissolved gold defects during alkanethiol assembled process, an atomic absorption spectroscopy (AAS) has been carried out in this paper, and the detection limit for the dissolved gold could be evaluated to be 15.4 ng/mL. The amount of dissolved gold from the substrates of gold plates as functions of immersion time, acid media, solvents and thiol concentration has been examined in the oxygen saturated solutions. In comparison with in situ QCM method, the kinetics behavior of the long-term gold corrosion on the gold plates in 1.0 mmol/L of n-dodecanethiol solution determined with AAS method was a slow process, and its corrosion rate on gold dissolution could be evaluated to be about 4.4 × 10 − 5 ng·cm − 2 ·s − 1 , corresponding to 1.3 × 10 8 Au atoms·cm − 2 ·s − 1 , that was much smaller than that of initial rate monitored with in situ QCM. Both kinetics equations obtained with QCM and AAS showed a consistent corrosion behavior on gold surfaces.