Wl. Yuan et al., Thin polypyrrole films formed on mica and alumina with and without surfactant present: characterization by scanning probe and optical microscopy, THIN SOL FI, 385(1-2), 2001, pp. 96-108
Chemical deposition of electrically conducting polypyrrole (PPy) thin films
on mica and alumina was carried out in aqueous solutions with and without
surfactant. Examination of film morphology and thickness by atomic force mi
croscopy (AFM) indicated a strong dependence of structure on the method of
preparation. Films grown in the absence of surfactant were thicker than 150
nm with wrinkles present, indicating the overcoming of film-substrate adhe
sion by internal film cohesion. Oxidative polymerization with surfactant al
lowed reproducible synthesis of very thin films (50 nm thickness) with impr
oved adhesion and suppressed formation of wrinkles. Experimental results ar
e discussed within the context of a Stranski-Krastanov model of film growth
. Film thickness and surface fractal dimensions were derived from AFM. Frac
tal analysis of Pq films on alumina helped discern their presence on the mi
croscopically rough substrate and quantitatively expressed the changes in s
ample color by surface roughness. (C) 2001 Published by Elsevier Science B.
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