Electrochemical and structural Characterization of self-assembled monolayers of mercaptoalcanoics acids on Au(111)

M. L. CAROT; V. A. MACAGNO; E. M. PATRITO

San Pedro, Brasil

Congreso; 54rd Annual Meeting of the International Society of Electrochemistry; 2003

The adsorption of Self-Assembled Monolayers (SAMs) based on thiol moieties adsorbed on metal substrates (Au, Ag, etc.) have been an overwhelming subject in the literature during the last decade. SAMs result to be very promising since they can be tailored to control the interfacial reactivity of metals. SAMs provide great contributions to the molecular design since they can be tuned for the specific and electrochemical sensing by the functionalization of the thiol template. SAMs with carboxylic acid terminal group have been used to immobilize biomolecules. In this sense, it is possible to build biosensors taking advantage of specifics interactions between functional terminal groups of the SAM and biomolecules. The first step in the study of these systems is the characterization of the thiol matrix which is necessary for a reliable device performance. In this communication we present the first results of the investigation related with the electrochemical and structural properties of single and mixed monolayers of 3-mercaptopropionic acid (MPA) and 11-mercaptoundecanoic acid (MUA) adsorbed on Au(111) by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Scanning Tunneling Microscopy (STM). The studies have been performed in buffer phosphate 25 mM, pH 7.2 because is the medium where most biomolecules maintain their structure and biologic activity.