It is well known that the presence of Al2O3 on the Al surface
inhibits the electron transfer process thus hindering the PPy depo-
sition and, hence, the polymer formation and growth. According to
Hülser and coworkers [8] the Al2O3/PPy interface formed in oxalic
acid
medium
evidenced
that
the
pretreatment
of
the
metal
strongly
influence the PPy film coherence and adhesion to the substrate and
also the film formation begins inside the pores of the oxide.
It has been reported that polypyrrole films electrosynthesized
in the presence of highly amphiphilic anionic surfactants present
good mechanical properties and high electrical conductivity due
to the higher degree of polymeric chain ordering attained with
these
dopants
[9,10].
Warren
and
coworkers
[10]
demonstrated
that
SDBS-doped
PPy
films
have
higher
chemical
stability,
their
electrical properties being maintained even after exposure to air at
ambient temperature for six months. Saidman and Vela [11] elec-
trodeposited polypyrrole on aluminum substrates from alkaline
solutions containing sodium dodecyl sulphate (SDS) and sodium
dodecylbenzene sulfonate (SDBS). They observed that the presence
of
surfactants
influences
the
morphology
of
the
polymer
producing
more
homogeneous
films
with
less
surface
roughness
than
those
formed in the absence of surfactants.
The influence of sulfonated electrolytes on the formation of
PPy
on
aluminum
was
studied
by
Naoi
et
al.
[12].
In
the
absence
of pyrrole, SDBS forms an Al2O3 barrier-type film with high