Electrochemical Characterization of Polyelectrolyte/Gold Nanoparticle Multilayers Self-Assembled on Gold Electrodes

Chirea, Mariana and García-Morales, Vladimir and Manzanares, José A. and Pereira, Carlos M. and Gulaboski, Rubin and Silva, A. Fernando (2005) Electrochemical Characterization of Polyelectrolyte/Gold Nanoparticle Multilayers Self-Assembled on Gold Electrodes. The Journal of Physical Chemistry B, 109 (46). pp. 21808-21817. ISSN 1520-6106

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Polyelectrolyte/gold nanoparticle multilayers composed of poly(L-lysine) (pLys) and mercaptosuccinic acid
(MSA) stabilized gold nanoparticles (Au NPs) were built up using the electrostatic layer-by-layer self-assembly
technique upon a gold electrode modified with a first layer of MSA. The assemblies were characterized using
UV-vis absorption spectroscopy, cyclic and square-wave voltammetry, electrochemical impedance spectroscopy,
and atomic force microscopy. Charge transport through the multilayer was studied experimentally
as well as theoretically by using two different redox pairs [Fe(CN)6]3-/4- and [Ru(NH3)6]3+/2+. This paper
reports a large sensitivity to the charge of the outermost layer for the permeability of these assemblies to the
probe ions. With the former redox pair, dramatic changes in the impedance response were obtained for thin
multilayers each time a new layer was deposited. In the latter case, the multilayer behaves as a conductor
exhibiting a strikingly lower impedance response, the electric current being enhanced as more layers are
added for Au NP terminated multilayers. These results are interpreted quite satisfactorily by means of a
capillary membrane model that encompasses the wide variety of behaviors observed. It is concluded that
nonlinear slow diffusion through defects (pinholes) in the multilayer is the governing mechanism for the
[Fe(CN)6]3-/4- species, whereas electron transfer through the Au NPs is the dominant mechanism in the case
of the [Ru(NH3)6]3+/2+ pair.

Item Type: Article
Subjects: Natural sciences > Chemical sciences
Divisions: Faculty of Agriculture
Depositing User: Rubin Gulaboski
Date Deposited: 30 Oct 2012 17:20
Last Modified: 05 Nov 2012 13:22
URI: https://eprints.ugd.edu.mk/id/eprint/99

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