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

JOURNAL OF ELECTROANALYTICAL CHEMISTRY - (Print)

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2013 vol. 712 p. 167 - 167

1572-6657

he 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. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) show a rather imperfect blocking behavior of the 2-MNA SAMS. This behavior corresponds to that obtained for microelectrode arrays, which is attributed to the access of ions through pinholes, defects and/or pores present in the SAM. The characteristics of ionisable groups exposed to the solution in the 2-MNA monolayers prepared by dipping in alkaline solutions were obtained by impedance measurements at different pH using the [Fe(CN)6]3/[Fe(