a) b - École Polytechnique de Montréal

in electrostatic repulsion and an enhancement of the amount of adsorbed polymer(Mattoso et al.,
2005; Raposo & Oliveira Jr, 2002). Several studies(Cheung, et al., 1997; M. K. Ram, M.
Salerno, M. Adami, P. Faraci, & C. Nicolini, 1999) did not succeed in assembling PANI/PSS
films in the presence of PANI in its neutral state.
Conductivity of PANI/PSS: some researchers have reported that with an increase of the number
of adsorbed PANI/PSS bilayers, electrical conductivity of the multilayer increases until a
saturation plateau is reached around the 13 th bilayer or the 25 th layer(Braga, et al., 2008;
Paloheimo, Laakso, Isotalo, & Stubb, 1995). Further deposition of layers showed no more
increase in the film’s electrical conductivity.
2.4.1.1.12 Characterization Techniques for LbL Deposited Layers
Commonly used methods used to characterize the internal structure of the multilayer and film
thickness could not be used in this research due to several limitations. Special techniques such as
UV-Vis, ellipsometry(Schwarz, Eichhorn, Wischerhoff, & Laschewsky, 1999), quartz crystal
microbalance (QCM)(Baba, Kaneko, & Advincula, 1999), streaming potential measurements
(SPM)(Schwarz, et al., 1999), atomic force microscopy(AFM)(Caruso, Furlong, Ariga, Ichinose,
& Kunitake, 1998), gravimetric measurement(Roy, et al., 2006), and x-ray and neutron
reflectivity(Schmitt et al., 1993) have been utilized to measure thickness or mass deposited on
the surface of each layer. Although the most commonly used method is UV-Vis, measurement of
light absorbance is impossible due to the black color of the PANI solution. .
As well, ellipsometry is one of the most appropriate techniques for showing the growth rate. As
the technique works with the reflection of emitted light, it is limited for substrates with curved
surfaces.
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