UBC Theses and Dissertations
Design and electrochemical characterizaton of novel functionalized polythiophene and polysiloxane derivatives Dalgakiran, Sibel
Metal-containing conducting polymers are a new and interesting class of materials that combine some of the redox properties of the conducting polymers and metal ions. In metal-containing conjugated polymers, there are several possible arrangements of the metal group relative to the backbone. This research focuses on the development of novel thiophene derivatives, with various side groups using different synthetic approaches and electrochemical polymerization. The resulting polymers could be excellent candidates for chemical sensors, solar cells, photoactive molecular devices and capacitors. Thiophene-based polymers containing η⁶-(haloarene)-η⁵-cyclopentadienyliron(II) hexafluorophosphate or ferrocene moieties were synthesized. Thiophene monomers which contained organoiron complexes were successfully polymerized using condensation polymerization and electropolymerization. The monomers and their precursors were characterized through nuclear magnetic resonance spectroscopy, infrared spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The thermal properties were studied with thermogravimetric analysis and differential scanning calorimetry. A novel series of functionalized thiophenes incorporating naphthol, coumarin and pyrene pendants were synthesized by Steglich esterification in the presence of DCC/DMAP and the synthesized monomers were electrochemically deposited onto glassy carbon and carbon fibre microelectrodes as active electrode materials. Another series was prepared with thiophenes using pendant terpyridine groups of varying functionality. The electrochemical impedance measurements were performed on surface-modified electrodes. Variation of capacitance values was explained according to the different fluorophore groups attached to the thiophene as well as the different substrates. The fluorescence behaviours and the surface morphological analysis were explained in detail. Additionally, using organoiron-mediated nucleophilic aromatic substitution, a number of allylamine-containing organoiron complexes were prepared. These materials were further hydrosilated with methyldiethoxyhydrosilane to generate cationic organoiron siloxanes and ferrocene-containing siloxane complexes. In situ cleavage of the ethoxy groups followed by the addition of H₂SO₄ resulted in the formation of polymeric materials. The synthesized polymers were individually blended with PAN/DMF matrix to form composite thin films. The films indicated porous surface morphology, increasing the surface activity.
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