Clay montmorillonite derivatized electrode as a template for electrosynthesis of conducting polymers and organic biomolecules
Abstract
In this thesis the electrochemical studies of a special type of polymers
namely conducting polymers (CPs) using cyclic voltammetry technique is
reported. This is a fast electroanalytical tool capable of providing qualitative
and quantitative information about electron transfer kinetics and probing the
subsequent chemical reactions. The CPs of interest are polyaniline,
polypyrrole, polynaphthol and polythiophene. Electrodeposition of the CPs
on both carbon and clay modified electrode surface is described.
The carbon graphite working electrode surface was modified/or
derivatized using a clay montmorillonite-bentonite. The elemental
composition of the modification material was obtained from x-ray
fluorescence (XRF) analysis.
Results obtained on derivitization of the working electrode surface
with clay montmorillonite treated with varying amounts of acid are
presented. The resultant changes in the population of Bronsted and Lewis
acid sites is shown to affect the redox properties of a conducting polymer,
polyaniline. The experimental observations are explained in terms of structural modification of clays on treatment with acid.
The electron transfer process in polyaniline electrodeposited on
various acidified clay modified electrodes fitted to the Allen-Hickling
equation for quasi-reversible redox systems reveal that the electron transfer
coefficients decrease (range from 0.642 to 0.171) as the films become
thicker signifying the poor efficiency of electron transfer in thick films.
Citation
Ph.D ThesisSponsorhip
University of NairobiPublisher
Depatment of Chemistry, University of Nairobi
Description
Ph.D Thesis