Jump to main content
Jump to site search

Issue 35, 2012
Previous Article Next Article

New insight into the electrochemical desorption of alkanethiol SAMs on gold

Author affiliations

Abstract

A combination of Polarization Modulation Infrared Reflection Absorption Spectroscopy (PMIRRAS) under electrochemical control, Electrochemical Scanning Tunneling Microscopy (ECSTM) and Molecular Dynamics (MD) simulations has been used to shed light on the reductive desorption process of dodecanethiol (C12) and octadecanethiol (C18) SAMs on gold in aqueous electrolytes. Experimental PMIRRAS, ECSTM and MD simulations data for C12 desorption are consistent with formation of randomly distributed micellar aggregates stabilized by Na+ ions, coexisting with a lying-down phase of molecules. The analysis of pit and Au island coverage before and after desorption is consistent with the thiolate–Au adatoms models. On the other hand, PMIRRAS and MD data for C18 indicate that the desorbed alkanethiolates adopt a Na+ ion-stabilized bilayer of interdigitated alkanethiolates, with no evidence of lying down molecules. MD simulations also show that both the degree of order and tilt angle of the desorbed alkanethiolates change with the surface charge on the metal, going from bilayers to micelles. These results demonstrate the complexity of the alkanethiol desorption in the presence of water and the fact that chain length and counterions play a key role in a complex structure.

Graphical abstract: New insight into the electrochemical desorption of alkanethiol SAMs on gold

Back to tab navigation

Publication details

The article was received on 23 Apr 2012, accepted on 19 Jul 2012 and first published on 19 Jul 2012


Article type: Paper
DOI: 10.1039/C2CP41291H
Citation: Phys. Chem. Chem. Phys., 2012,14, 12355-12367
  •   Request permissions

    New insight into the electrochemical desorption of alkanethiol SAMs on gold

    E. Pensa, C. Vericat, D. Grumelli, R. C. Salvarezza, S. H. Park, G. S. Longo, I. Szleifer and L. P. Méndez De Leo, Phys. Chem. Chem. Phys., 2012, 14, 12355
    DOI: 10.1039/C2CP41291H

Search articles by author

Spotlight

Advertisements