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Updated: May 30, 2026

Investigating Single Molecule Adhesion by Atomic Force Spectroscopy
Published on: February 27, 2015
Electrochemical investigations on stability and protonation behavior of pyridine-terminated aromatic self-assembled
Mutlu Iskender Muglali1, Asif Bashir, Andreas Terfort
1Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, Germany. m.muglali@mpie.de
Abstract:
Based on electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), Au(111) electrodes modified by self-assembled monolayers (SAMs) of a homologous series of pyridine-terminated thiols with aromatic backbones have been investigated. An important correlation between the chain structure and film integrity in electrolytic media was found. Monolayers with odd numbers of methylene spacers in the molecular chain showed superior barrier properties compared to even numbered counterparts. A positive influence of an increase in the number of attached phenyl rings on the integrity of SAMs was observed. Furthermore, cathodic desorption of the investigated SAMs is characterized by multiwave desorption peaks and extraordinarily large cathodic charges indicating an unusual desorption process. Moreover, protonation behavior of the SAMs has been investigated by X-ray photoelectron spectroscopy (XPS) and electrochemical methods. Protonation has been found to be reversible and surface pK(a) values have been determined to be around 5 for all investigated monolayers.
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