Preparation and characterization of self assembled monolayers of 2-mercaptonicotinic acid on Au(111)

DIEGO E. PISSINIS; OMAR E. LINAREZ PÉREZ; FERNANDO P. COMETTO; MANUEL LÓPEZ TEIJELO

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Lugar: Amsterdam; Año: 2014 vol. 712 p. 167 - 167

bstract: The characterization by cyclic voltammetry, impedance spectroscopy and SERS measurements of 2-mercaptonicotinic acid (2-MNA) monolayers formed under different conditions on Au(111) surfaces, is reported. Self-assembled 2-MNA monolayers on Au(111) in alkaline solutions desorbs reductively from the gold surface at -0.76 V (vs. ECS). From desorption experiments, the value of the surface concentration was estimated, resulting similar to that reported for related aromatic molecules. After 30 min of dipping time 2-MNA layers are closely packed on the Au(111) surface and the structure of the SAM is stabilized. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed for obtaining structural information of the monolayers by analysis of the change of the kinetics of the electron transfer reaction for the Fe2+/Fe3+ redox probe on the SAM. The results of CV and EIS show a rather imperfect blocking behaviour of the 2-MNA SAM and the Fe2+/Fe3+ redox pro