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Layer‐by‐Layer Self‐Assembled Redox Polyelectrolytes on Passive Steel
Author(s) -
Völker Edgar,
Calvo Ernesto J.,
Williams Federico J.
Publication year - 2008
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/ijc.48.3-4.305
Subject(s) - chemistry , polyelectrolyte , cyclic voltammetry , osmium , x ray photoelectron spectroscopy , ellipsometry , layer by layer , allylamine , redox , voltammetry , electron transfer , inorganic chemistry , layer (electronics) , electrochemistry , analytical chemistry (journal) , polymer , chemical engineering , polymer chemistry , electrode , thin film , ruthenium , nanotechnology , photochemistry , organic chemistry , materials science , catalysis , engineering
Abstract Steel samples were passivated in 0.1 M NaOH solutions at 0.3 V vs. Ag/AgCl (3 M KCl) and then poly(allylamine) derivatized with osmium pyridine‐bipyridine‐chloride complex and poly‐(vinylsulfonate) were sequentially self‐assembled electrostatically layer‐by‐layer. The resulting electrodes were examined by cyclic voltammetry, ellipsometry, and X‐ray Photoelectron Spectroscopy (XPS). These studies demonstrate the formation of a redox polyelectrolyte multilayer onto the passive film protecting the ferrous metal. As the number of deposited polyelectrolyte layers increases there is an increase in the measured thickness of the self‐assembled film. The rate of thickness growth in osmium polymer film with the number of deposition cycles is slower for films thinner than ∼30 nm. Cyclic voltammetry shows that the electron transfer rate to the outer sphere osmium complex tethered to the polymer backbone is much slower for the multilayer on passive iron than on gold surfaces. This is in agreement with the well‐known behavior of soluble redox couples on passive metals and with electrochemical tunelling spectroscopy.