Mt. Giacomini et al., SPECTROSCOPIC ELLIPSOMETRY INVESTIGATION OF THE REDOX PROCESS OF POLYPYRROLE IN SEVERAL AQUEOUS-SOLUTIONS, Surface science, 409(3), 1998, pp. 465-473
In this work, the properties of polypyrrole films electrochemically gr
own on platinum substrates from different aqueous solutions were studi
ed using a spectroscopic ellipsometry technique at several electrode p
otentials. The electrolytes were: NaCl 0.5 M, CsCl 0.5 M, Na2SO4 0.5 M
with pH = 4.5, and H2SO4 0.5 M (pH = 0.4). In all electrolytes with p
H 4.5, for electrode potentials above 0.0 V vs. SCE, the polymer chain
s are in the highest state of oxidation, indicating that polarons are
not present to a large extent. In a more acidic electrolyte, the film
properties and oxidation mechanism are different from those under high
er pH conditions. In all electrolytes, there is an increase in the thi
ckness and degree of hydration of the film with polymer oxidation. (C)
1998 Elsevier Science B.V. All rights reserved.