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Self-Assembled Monolayers on Electrodes

Electroanalytical Methods

  1. Harry O. Finklea

Published Online: 15 SEP 2006

DOI: 10.1002/9780470027318.a5315

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Finklea, H. O. 2006. Self-Assembled Monolayers on Electrodes. Encyclopedia of Analytical Chemistry. .

Author Information

  1. West Virginia University, Morgantown, USA

Publication History

  1. Published Online: 15 SEP 2006

Abstract

Alkanethiols and related molecules spontaneously adsorb from solution or vapor phase onto oxide-free metals, especially gold, to form close-packed oriented monolayers. The ease and flexibility of the self-assembly process provides a convenient method for altering the properties of the metal as an electrode. The close-packed hydrocarbon layer blocks access of most solution species to the electrode surface. Consequently, interfacial capacitances are markedly reduced and most electron-transfer reactions are strongly inhibited. The monolayers also provide a foundation for attachment of additional molecules or molecular layers to electrodes. Self-assembled monolayers (SAMs) on electrodes have been used in voltammetric methods to improve the analytical sensitivity and to impart greater selectivity towards specific analytes. Redox molecules have been anchored at fixed and controllable distances from the electrode surface, thereby permitting the study of electron-transfer kinetics over long distances and at large driving forces. The ability of SAMs to inhibit metal corrosion and to promote better adhesion of electroactive polymers has been demonstrated.