Chemistry Reference
In-Depth Information
Fig. 1
Influence of aniline to template ratio on conductivity for enzymatic PANI/DODD (
dia-
monds
) and enzymatic PANI/DBSA (
squares
). (Reprinted with permission from Rumbau et al.
[
38
].
c
2007, Elsevier)
is reflected in the fact that the CMC value for DODD is higher than that for DBSA
(7
10
−
3
M, respectively). Furthermore, in a bifunctional surfac-
tant, each micelle is expected to be composed of a lower number of individual
molecules than micelles created by monofunctional surfactants and, consequently,
to be smaller in size. Light scattering measurement verified this assumption, where
micelles with diameters of
10
−
3
×
and 1
.
6
×
4 nm and 5 nm were observed for DODD and DBSA,
respectively. It was therefore assumed that, for the same surfactant concentration,
there are more micelles formed from a bifunctional surfactant than from monofunc-
tional surfactant at the same concentration.
The content of anionic charges and the anionic template surface for complex for-
mation in the media should thus be higher. The solubility of the polymer complex
is explained by the anionic charges on the template, and that a percentage of these
anionic charges must remain free to keep the complex in solution. A system with
a larger anionic surface would result in higher complexation with anilinium cations
on the surface and, consequently, a higher polymerization conversion before pre-
cipitation occurred. This higher local anilinium cation concentration should lead to
higher molecular weights and, consequently, higher conductivity in the product.
thesized under the same conditions, the conductivity of the PANI/DODD complex
is indeed higher than that of the PANI/DBSA. Furthermore, the DODD tem-
plate allows the use of a higher aniline to template ratio before precipitation
occurs. PANI/DBSA complexes show precipitation at ratios close to 2.5:1 whereas
PANI/DODD complexes remain in solution even at a ratio of 4:1.
<
4
First Enzymatic Polymerizations of EDOT
Oxidoreductases such as HRP, obtained from natural and renewable sources, have
been known to catalyze the polymerization of aniline and phenol-based monomers
