Effects of dopants on the conductivity of polyaniline Synthesized by chemical oxidation and electrochemical methods
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Date
2019-08-25
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KNUST
Abstract
Polyaniline salts (PANI-ES) were synthesized by chemical and electrochemical oxidation using
primary dopants such as HCL, HNO3, H2SO4 and CH3COOH and the aniline as the monomer.
All the synthesized PANI have resulted in emeraldine salts form as indicated by dark green
colour of the salts. Various characterization techniques employed were UV-Visible spectroscopy,
FT-IR and Cyclic voltammetery studies. All these techniques confirm the various properties of
PANI. The characteristic bands in UV-Visible spectra of the samples indicate that effective
doping has occurred in the synthesized polymer. Quinoid and benzenoid peaks at 1553-1596 cm-
1
and 1437 – 1496 cm-1 respectively were observed in all the samples. The band gaps for all the
samples, both bulk and thin film, were obtained using the absorption spectra and Stern relation.
PANI-H2SO4 had the least band gap for both bulk and thin film samples whereas PANI
CH3COOH had the highest band gap. The voltammogram showed the various oxidation states
during the electrochemical deposition at potential of 0.8 V. Four probe method was used to study
the conductivity of both thin and bulk samples. The conductivity values for PANI-H2SO4 were
found to be highest i.e. 1.183 S.cm−1 and 3.424 S.cm−1 for bulk and thin film respectively
Description
A Thesis submitted to the Department Of Physics, Kwame Nkrumah University of
Science and Technology, in partial fulfillment of the requirement for the degree of
MASTER OF PHILOSOPHY (MATERIALS SCIENCE)
College of Science