Congresos y reuniones científicas
Título:
Structure and Stability of a,w-alkanedithiols Adlayers on Au(111): An Electrochemical Study
Autor/es:
F. P. COMETTO, C. A. CALDERÓN, E. M. EUTI, D. K. JACQUELÍN, M. A. PÉREZ, E. M. PATRITO AND V. A. MACAGNO
Reunión:
Simposio; 10th International Symposium on the Passivation of Metals and Semiconductors and the Properties of Thin Oxide Layers; 2011
Resumen:
Structure and stability of self-assembled adlayers of alkanedithiols (DTs) were studied with electrochemical techniques: reductive desorption experiments, redox couples cyclic voltamperometry and electrochemical impedance spectroscopy. Adlayers for DTs with different number of carbon atoms in the chain length (2-9) were formed in solvents with different polarity (ethanol, n-hexane and toluene), by controlling the O2 levels, and by using a post-deposition treatment with mild reducing agents to investigate the role played by the disulphide bond (S-S) formation (whether interlayer or intralayer) in determining the final structure and stability1-2. Multilayer is the most favored structure for adlayers of short chain length DTs (ethanedithiol) when formed by dipping in solutions with solvents of high polarity (ethanol). As the chain length increases, the multilayer structure is not observed although intralayer formation of S-S bonds is detected. DTs adlayers with a monolayer structure are easily obtained by using low polarity solvents in the dipping solution. The treatment of adlayers with mild reducing agents proved to be a very effective procedure to transform multilayers into monolayers as well as to re-activate the adlayer ending groups by reduction of the S-S bonds. Adlayers formed in toluene dipping solutions exhibit DTs molecules in a lying-down or U-loop structures.