Electrochemical Synthesis and Characterization of Polymers and Copolymers of 3-Hexylthiophene, 3-Methylthiophene and 3-Octylthiophene
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Date
2005-06
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Addis Ababa Universty
Abstract
The electrochemical polymerizations and characterization studies were made for the
monomers 3-hexylthiophene (3HT), 3-methylthiophene (3MT) and 3-octylthiophene
(3OT).The electrochemical properties of the corresponding polymers poly(3-hexylthiophene)
(P3HT) , poly(3-methylthiophene) (P3MT) and poly(3-octylthiophene) (P3OT) were also
studied in a monomer free LiClO4 - acetonitrile solutions. Copolymers were electrochemically
synthesized from the monomers and showed intermediate electrochemical properties between
their corresponding homopolymers. The first copolymer obtained was the copolymer of 3HT
and 3OT (poly(3HT-co-3OT)) from 1:1.5 volume ratio of 3HT to 3OT at a potential of 1.70 V
in 0.1 M LiClO4 - acetonitrile solution and the second was the copolymer of 3MT and 3OT,
(poly(3MT-co-3OT)) from 1:2.5 volume ratio of 3HT to 3OT at a potential of 2.00 V in
LiClO4 - acetonitrile solution.
The electrocatalytic effects of the polymers and copolymers electrochemically modified on
platinum disc electrode were examined using ferricyanide redox system. Among the polymers
examined a copolymer of 3MT and 3OT showed the best electrocatalytic effect. Based on this
result the electrocatalytic effect of this copolymer was further studied on selected
environmental and biological samples. It was found that poly(3MT-co-3OT) modified
platinum electrode is highly selective and sensitive towards
a) detection of ferricyanide with the detection limit of 20 M, in 1 M aqueous potassium
nitrate solution using cyclic voltammetry,
b) simultaneous detection of the isomeric compounds hydroquinone and catechol with a
detection limit of 40 M for both analytes in phosphoric acid solution pH = 0.5 using
differential pulse voltammetry,
c) detection of ascorbic acid with a detection limit of 80 M in phosphate buffer solution
pH = 4.0 using differential pulse voltammetry,
d) selective detection of catechol in the presence of the known interferance asorbic acid
with a detection limit of 80 µM in phosphate buffer solution pH = 4.0 using
differential pulse voltammetry.
Key words; poly(3-hexylthiophene), poly(3-methylthiophene), poly(3-octylthiophene),
poly(3HT-co-3OT), poly(3MT-co-3OT), Electrochemical Polymerization, Electrocatalysis
Description
Keywords
poly(3-hexylthiophene); poly(3-methylthiophene); poly(3-octylthiophene); poly(3HT-co-3OT); poly(3MT-co-3OT); Electrochemical Polymerization; Electrocatalysis