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Combining the molecular self-assembly properties and thin film
preparation technique, we are able to synthesize highly-ordered
conducting polyaniline films. First, the substrate (silicon
wafer or glass ) was modified with Aniline-contanining silane
to form a single layer organic film. Polymer film deposition
was carried out by contacting the modified substrate with
external oxidant and monomer. The strong adhesion between
polyaniline film and substrate, we are able to isolate the
intermediate from short polymerization time , and observe the
change of color in both solution and film to deduce the
polymerization mechanism. Aniline molecules first oxidized ,
then couple to the dimer , the dimers then couple into
tetramers. The tetrames polymerize fast to form the intermediate
which is a long chain polymer with several free radicals in the
backbone. The intermediate then couple with the oligomers in
solution to form polyaniline. Polymer films isolate from
different polymerization conditions (for example : oxidant/
monomer ratio) resulting in different properties, such as
surface morphology，conductivity and the degree of oxidation and
protonation. Among them the degree of oxidation and protonation
effect the position of uv/vis absorbance maximum between
reflectance and transmittance mode. Aniline and its
derivative, o-anisidine are deposited, in order, on substrate
to form double-layered contducting polymer films. The optical
and electric properties of the double-layered film are different
from the individul components. This indicates that there is
some interaction between each layer of polymer. This discovery
provides a new strategy for preparing novel materials throught
polymer blending.
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