Structure of Mixed Carboxylic Acid Terminated Self-Assembled Monolayers: Experimental and Theoretical Investigation

L. CAROT; V. MACAGNO; P. PAREDES OLIVERA; E. M. PATRITO

American Chemical Asociation

Lugar: Washington; Año: 2007 vol. 111 p. 4294 - 4294

font face="Times New Roman" size="2"> The structure and stability of mixed self-assembled monolayers (SAMs) of 3-mercaptopropionic acid (MPA) and 11-mercaptoundecanoic acid (MUA) prepared by immersion in ethanolic solutions were studied by cyclic voltammetry, electrochemical impedance spectroscopy, ellipsometry, and STM as a function of the thiol composition of the forming solution. The presence of a single reductive desorption peak in the voltammograms of the mixed SAMs and the lack of phase segregation observed by STM support the formation of homogeneous SAMs despite the large chain length difference between MPA and MUA. To explain the driving force leading to the formation of a homogeneous mixture, intermolecular interactions within the SAM were investigated using density functional theory. The carboxyl groups of adjacen