The increasing demand for energy and the pressure to reduce reliance on fossil fuels encourages the development of devices to harness clean and renewable energy. Solar energy is a large enough source to fulfill these demands, however, in order to overcome its daily and seasonal variability, it has been proposed that sunlight be harvested and stored in the form of chemical fuels. One potential approach is the photosynthetic splitting of water to store solar energy in the simplest chemical bond, H–H, using a device that includes: semiconducting microwire arrays as light harvesting components, redox catalysts, and a membrane barrier for separating the products of water redox reactions.. However, the harvested solar energy can be lost across the system and it is critical to characterize the electrical properties of each component within the system to quantify how much of this energy will ultimately be coupled to the water splitting reactions. The aim of this research is to develop approaches for characterization of a proposed system of this kind, incorporating individual semiconductor microwires as photoelectrodes (with no redox catalysts) embedded into a candidate conducting polymer membrane to form a single functional unit. Semiconductor microwires were isolated and using a novel contact formation approach with tungsten probes in a standard probe station, and their current versus voltage properties were characterized. This approach is of particular interest when ii considering the limitations of conventional contact formation approaches (e.g. thermal evaporation of contact metals), arising from the small dimensions of the microwires and also the incompatibility of these techniques with many microwire/polymer structures due to the unwanted interactions between polymers, photoresists, etchants and the high temperature lithographic processes. The electrical properties of different microwires and also the junctions between microwires and two candidate polymers were studied. Specifically, the combination of methyl-terminated silicon microwires and PEDOT:PSS:Nafion demonstrated promising behavior, with a total DC resistance of approximately 720 kΩ (i.e. losses < 16 mV at maximum available photocurrent), making it a suitable candidate for the use in the proposed system. The outcome of these research may be applied to many applications including semiconducting microstructures and conducting polymers.

Synthesis of 2-[(3-thienylcarbonyl)oxy]ethyl 3-thiophene carboxylate (TOET), 2,3-bis-[(3-thienylcarbonyl)oxy]propyl 3-thiophene carboxylate (TOPT), and 3-[(3-thienylcarbonyl)oxy]-2,2-bis{[(3-thienylcarbonyl)oxy]}propyl 3- thiophene carboxylate (TOTPT), and their copolymerization either with thiophene or pyrrole were achieved. The chemical structures of the monomers were investigated by Nuclear Magnetic Resonance Spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Electrochemical behavior of the monomers and copolymers were studied by cyclic voltammetry (CV). The resultant conducting copolymers were characterized via FTIR, Thermal Gravimetry Analysis (TGA), Differential Scanning Calorimetry (DSC), and morphologies of the films were inspected by Scanning Electron Microscope (SEM). Conductivities of the samples were measured by using four-probe technique. The electrochromic and spectroelectrochemical properties of the copolymers were investigated.

Synthesis and characterization of conducting copolymers were achieved by using thiophene-3-yl acetic acid cholesteryl ester (CM) and poly (3-methylthienyl methacrylate) (PMTM). A new polythiophene containing a cholesteryl side chain in the &amp / #946 / -position was chemically polymerized in nitromethane/carbon tetrachloride using FeCl3 as the oxidizing agent. Polymerization was also achieved by constant current electrolysis in dichloromethane. Subsequently, conducting copolymers of thiophene-3-yl acetic acid cholesteryl ester (CM), PCM1 (obtained from chemical polymerization method), PCM4 (obtained from constant current electrolysis) with pyrrole were synthesized. Thiophene functionalized methacrylate monomer (MTM) was synthesized via esterification of the 3-thiophene methanol with methacryloyl chloride. The methacrylate monomer was polymerized by free radical polymerization in the presence of azobis (isobutyronitrile) (AIBN) as the initiator. Graft copolymers of poly (3-methylthienyl methacrylate)/polypyrrole, (PMTM2/PPy) and poly (3-methylthienyl methacrylate)/polythiophene, (PMTM2/PTh) were synthesized by constant potential electrolyses. PMTM2 coated Pt electrodes were utilized as the anode in the polymerization of pyrrole and thiophene. Moreover, oxidative polymerization of PMTM1 was studied by galvanostatic and chemical techniques. Characterizations of the samples were performed by CV, FTIR, NMR, DSC, TGA and SEM analyses. Electrical conductivities were measured by the four-probe technique. Immobilization of invertase in conducting copolymer matrices, poly (3-methylthienyl methacrylate) with pyrrole and thiophene was achieved by constant potential electrolysis using the sodium dodecyl sulfate as the supporting electrolyte. Polythiophene was also used for immobilization matrices. Cholesterol oxidase has been immobilized in conducting copolymer of thiophene-3-yl acetic acid cholesteryl ester with polypyrrole (CM/PPy) and polypyrrole (PPy) by the electropolymerization method. p-Toluene sulfonic acid was used as a supporting electrolyte. Kinetic parameters (Kinetic parameters / Vmax and Michaelis-Menten constant / Km) and operational stability of enzyme electrodes were investigated. Surface morphology of the films was also examined.

Synthesis and characterization of thiophene ended poly-&amp / #949 / -caprolactone (PCL) and oxalic acid dithiophen-3-yl methyl ester (ODME) and their copolymers with both pyrrole and thiophene were achieved. Chemical structure of the precursor polymer and monomer were investigated Redox behavior of polymer and monomers were determined by Cyclic Voltammetry (CV). Structural characterization of samples were carried out by 1H, 13C Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Conductivities of the films were measured by using four probe technique. Thermal analyses of conducting copolymers were investigated via Differential Scanning Calorimetry (DSC) and Thermal Gravimetry Analysis (TGA). The morphologies of the copolymer films were examined by Scanning Electron Microscopy (SEM). Electrochromic and spectroelectrochemical behavior of the copolymers were investigated, and their ability of employment in device construction has been examined.

In the first part of this work, the structural and thermal characteristics of polyacrylonitrile, polyacrylonitrile films treated under the electrolysis conditions in the absence of thiophene, polythiophene and the mechanical mixture and a conducting copolymer of polyacrylonitrile/polythiophene have been studied by pyrolysis mass spectrometry technique. The thermal degradation of polyacrylonitrile occurs in three steps / evolution of HCN, monomer, low molecular weight oligomers due to random chain cleavages are followed by cyclization and dehydrogenation reactions yielding crosslinked and unsaturated segments. Pyrolysis of the treated polyacrylonitrile films indicated decrease in the yields of monomer and oligomers, and increase in the amount of products stabilized by cyclization reactions were detected. Polythiophene degrades in two steps / the loss of the dopant and degradation of polymer backbone. The evolution profiles of polythiophene based products from polythiophene/polyacrylonitrile showed nearly identical trends with those recorded during the pyrolysis of pure polythiophene. However, evolution of HCN and the degradation products due to the homolytic cleavages of the polymer backbone continued through out the pyrolysis indicating a significant increase in their production. Furthermore, the yield of thermal degradation products associated with decomposition of the unsaturated cyclic imine segments decreased. A careful analysis of the data pointed out presence of mixed dimers confirming copolymer formation. In the second part of this work, a poly(acrylonitrile-co-butadiene) sample involving monomer units having quite similar molecular weights have been analyzed to investigate the limits of the pyrolysis mass spectrometry technique. Pyrolysis of aged poly(acrylonitrile-co-butadiene) indicated oxidative degradation of the sample. Keywords: conducting copolymer, polyacrylonitrile, polythiophene, polybutadiene, direct pyrolysis mass spectrometry

Immobilization of tyrosinase in conducting copolymer matrices of pyrrole functionalized polydimethylsiloxane/polypyrrole (PDMS/PPy) were achieved by electrochemical polymerization. The polysiloxane/polypyrrole/tyrosinase electrode was constructed by the entrapment of enzyme in conducting matrices during electrochemical copolymerization. Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were investigated for immobilized enzyme. Enzyme electrodes were prepared in two different electrolyte/solvent systems. The effect of supporting electrolytes, p-toluene sulfonic acid and sodium dodecyl sulfate on the enzyme activity and film morphology were determined. Temperature and pH optimization, operational stability and shelf-life of enzyme electrodes were also examined. Phenolic contents of green and black tea were determined by using enzyme electrodes.

In the first part of this study, the structtural and thermal characterization of electrochemically and chemically polymerized poly(paraphenylene vinylene), (PPV), have been investigated by direct pyrolysis mass spectrometry. Thermal characteristics, and degradation products of electrochemically prepared poly(paraphenylene vinylene). Pyrolysis study indicated that thermal decomposition of PPV occurs at least two steps. The first being due to the loss of supporting electrolyte present and the second being decomposition of the polymer backbone.In the second part of the study, direct insertion probe pyrolysis mass spectrometry (DIP-MS) technique was used to perform the thermal and the structural characterization of electrochemically synthesized polyaniline,PANI. The effect of dopant used (HCL, HNO3 and H2SO4) and synthesis period have been investigated. For all the samples studied, three main thermall degradation stages have been recorded / evolution of low molecular weight species, evolution of dopant based products and evolution of degradation products of polymer.

Terephthalic acid bis-(thiophen-3-ylmethyl)thioester (TTMT) was synthesized via the reaction of thiophen-3-ylmethanethiol with terephthaloyl dichloride. Nuclear magnetic resonance (1H-NMR) and Fourier transform infrared (FTIR) spectroscopies were utilized for the characterization of the monomer. This 3-functionalized thiophene monomer was polymerized in the presence of thiophene (Th) and pyrrole (Py) upon constant potential application in acetonitrile/tetrabutylammonium tetrafluoroborate (TBAFB). The resulting copolymers were characterized via cyclic voltammetry (CV), FTIR, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), four-probe technique conductivity measurement and UV-Vis spectroscopy. Spectroelectrochemical analysis of P(TTMT-co-Th) revealed &amp / #960 / to &amp / #960 / * transition at 476 nm with a band gap of 2.0 eV whereas, &amp / #955 / max and Eg were found as 375 nm and 2.4 eV for P(TTMT-co-Py), respectively. Dual type electrochromic devices (ECDs) of P(TTMT-co-Th) and P(TTMT-co-Py) with poly(3,4-ethylenedioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, switching ability, open circuit memory and stability of the devices were examined by UV-Vis spectroscopy and cyclic voltammetry. The device P(TTMT-co-Th)/PEDOT switches between brown and blue upon application of 0.0 V and +2.6 V, respectively with 11% optical contrast and 1.1 s as the switching time. On the other hand, P(TTMT-co-Py)/PEDOT ECD exhibits greenish yellow, grayish red and blue colors with the application of -2.4 V, 0.0 V and +0.8 V, respectively and the contrast between extreme potentials was 17.5% with a switching time of 1.6 s. 1-(4-Fluorophenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole (FPTP) was synthesized and polymerized both chemically and electrochemically. Several analytical techniques, such as NMR, FTIR, CV, gel permeation chromatography (GPC), four-probe conductivity measurement, SEM were utilized when applicable. Spectroelectrochemistry experiments reflected a &amp / #960 / to &amp / #960 / * transition at 398 nm with a band gap energy of 1.94 eV for the polymer. A dual type electrochromic device (ECD) of PFPTP and poly(3,4-ethylenedioxythiophene) (PEDOT) was constructed. The device switches between yellowish brown and blue upon application of &amp / #8211 / 0.8 V and +1.1 V, respectively. Optical contrast was calculated as 19.4% with a switching time of 1.4 s at maximum contrast point.

2,5-Di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole (DTTP) was synthesized via reaction of 1,4-di(2-thienyl)-1,4-butanedione with p-toluidine in the presence of catalytical amount of p-toluenesulfonic acid (PTSA). Homopolymer P(DTTP) was achieved both by chemical and electrochemical techniques. Chemical polymerization of the monomer yielded a soluble polymer. The average molecular weight was determined by gel permeation chromatography (GPC) as Mn: 2.5x103 g/mol. The monomer was electrochemically polymerized in the presence of LiClO4, NaClO4 (1:1) as the supporting electrolyte in acetonitrile. Copolymer of DTTP in the presence of EDOT was synthesized via potentiodynamic method in ACN/ NaClO4/LiClO4 (0.1 M) solvent-electrolyte couple. Structural characterizations of samples were carried out via 1H, 13C Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Electrochemical behaviors of monomer and polymers were determined by Cyclic Voltammetry (CV). The morphologies of the polymer films were examined by Scanning Electron Microscopy (SEM). Conductivities of the films were measured by four probe technique. Electrochromic and spectroelectrochemical behavior of the polymers coated on ITO glass electrode were investigated, and their ability of employment in device construction was examined. Spectroelectrochemistry analysis of P(DTTP) revealed an electronic transition at 428 nm corresponding to &amp / #1087 / &amp / #8211 / &amp / #1087 / * transition with a band gap of 2.1 eV whereas P(DTTP-co-EDOT) revealed an electronic transition at 448 nm corresponding to &amp / #1087 / - &amp / #1087 / * transition with a band gap of 1.8 eV. Electrochromic investigations showed that P(DTTP) switches between greenish yellow and blue while P(DTTP-co-EDOT) was found to be multichromic, switching between red, yellow and blue. Switching time of the polymers was evaluated by a kinetic study upon measuring the percent transmittance (%T) at the maximum contrast point. Dual type polymer electrochromic devices (ECDs) based on P(DTTP) and P(DTTP-co-EDOT) with poly(3,4-ethylenedioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts and optical memories.

Conducting polymers display properties such as high conductivity, light weight and redox activity giving them great potential for use in many applications. Polythiophenes have proved to be particularly useful because they are readily functionalised and have good chemical stability. The purpose of this work was to investigate the effect of electron-withdrawing and electron-donating substituents on the synthesis and properties of polythiophenes. Initial work entailed the synthesis of a series of styryl-substituted terthiophenes. Polymerisation of these materials using both chemical and electrochemical methods was found to produce predominantly short chain oligomers (n < 4) and insoluble material that could not be further processed. An analogous series of styryl-substituted terthienylenevinylene materials were electrochemically oxidised for comparison to the terthiophene series. These materials were also found to produce predominantly dimer and short oligomers, but with the expected higher conjugation length than the corresponding terthiophene oligomers. To enhance polymerisation and increase the solubility of the resulting materials, the polymerisation of styryl-terthiophenes with alkyl and alkoxy functionalities was investigated. The properties of the resulting polymeric materials were determined using electrochemistry, mass spectrometry, spectroscopy and microscopy. The alkoxy substituted polymer was found to have a longer average polymer length than the corresponding alkyl derivative (~n = 11 compared to ~n = 6), but was less soluble (78% compared to 100%). It was found, however, that by increasing the alkoxy chain length from 6 carbons to 10 carbons, the solubility of the polymer could be increased to 97% without affecting the average polymer length. The alkoxy-substituted polymers were observed to be very stable in the oxidised, conducting state compared to the alkyl-substituted polymer, which appeared to be more stable in the neutral, non-conducting state. It was found that these soluble materials could be separated into fractions of different length polymers by using sequential soxhlet extractions in different solvents. Preliminary investigations were made into the suitability of these soluble oligomeric and polymeric materials for use in photovoltaic, actuator and organic battery applications and promising results were achieved for actuator and battery functions. In addition, the solubility of these materials allowed nano- and micro-structured fibre and fibril surfaces to be prepared for use in high surface area electrodes.