Ion-Exchange and Charge Transport in Films of Conducting Polymer and Composite

This thesis was concerned with the improvement of novel modified electrodes based on polyaniline (Pani) and its copolymers with o-aminophenol (o-AP) and o-toluidine (o-OT) and the investigation of their defluoridation properties, and further with the enhancement of the charge transport of Pani and polypyrrole (PPy) via multiwall carbon nanotubes (MWCNTs) in Ethaline. The principle of electrochemical ion-exchange modified electrodes is based on the doping/dedoping process of conducting polymer films. This feature makes it possible to remove undesirable ions, such as fluoride, from aqueous solution. The fabrication of Pani and its copolymers with o-AP/o-OT, carried out under optimal conditions by EQCM, gave an excellent opportunity to test for the removal of fluoride ions at pH 6.60 from water without chemical contamination of the copolymer. Pani, and its copolymers with o-AP/o-OT, poly(aniline-co-o-aminophenol) (Pani-PAP) and poly(aniline-co-o-toluidine) (Pani-POT), can theoretically take up about 91.2 mg g-1 fluoride ions per redox site of polymer film. Experiments indicated that the Pani, Pani-PAP and Pani-POT films removed 51.6 ± 1.0 mg g-1, 65.0 ± 0.6 mg g-1 and 66.8 ± 1.8 mg g-1, respectively, of fluoride ions per redox site of each (co)polymer film. This demonstrates that the copolymerisation of aniline with its derivatives enhanced the defluoridation properties of Pani. Pani and PPy are also promising materials for energy storage devices. The presence of MWCNTs to some extent enhanced both the electrochemical properties and mechanical stability in Ethaline, which maintains high efficiency and high-quality depositions through the use of the EQCM technique. The specific mass capacitances of these composite films were determined to be 1170.1 ± 44.7 F g-1 and 120.5 ± 5.4 F g-1 for Pani/MWCNTs and PPy/MWCNTs, respectively.