A monomer, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl) benzenamine (SNS-NH2), was synthesized via the reaction of 1,4-di(2-thienyl)-1,4-butanedione with benzene-1,4-diamine. Chemical polymerization of the monomer yielded a polymer which was completely soluble in organic solvents. The chemical structures of both the monomer and the polymer were characterized by Nuclear Magnetic Resonance Spectroscopy (1H-NMR and 13C-NMR) and Fourier Transform Infrared (FTIR) Spectroscopy. The average molecular weight of the chemically synthesized polymer was determined by Gel Permeation Chromatography (GPC) as Mn = 2.2x103 g/mol. The electrochemical oxidative polymerization of SNS-NH2 was carried out via potentiodynamic electrolysis in the presence of LiClO4, NaClO4 (1:1) supporting electrolyte in acetonitrile. Electrochemical copolymerization of SNS-NH2 in the presence of 3,4-ethylenedioxythiophene (EDOT) was achieved in acetonitrile (ACN) / NaClO4/LiClO4 (0.1M) solvent-electrolyte couple via potentiodynamic electrolysis. Conductivities of samples were measured by four probe technique. Cyclic Voltammetry (CV) and Ultraviolet&ndash / Visible Spectroscopy were used to investigate electrochemical behavior of the monomer and redox reactions of conducting polymers. Surface morphologies of the polymer films were investigated by Scanning Electron Microscope (SEM). Second part of the study was devoted to investigate the one of most interesting property of conducting polymers, the ability to switch reversibly between the two states of different optical properties, &lsquo / electrochromism&rsquo / . The electrochromic properties of the conducting polymers were investigated via spectroelectrochemistry, kinetic and colorimetry studies. Spectroelectrochemistry analysis of homopolymer, P(SNS-NH2), reflected electronic transitions at 376 and 650 nm indicating &amp / #960 / -&amp / #960 / * transition and polaron band formation respectively. The polymer has an electronic bandgap of 2.12 eV with a yellow color in the fully reduced form and a blue color in the fully oxidized form. Switching ability of the homopolymer was evaluated by kinetic studies upon measuring the % transmittance as 20.7 % at the maximum contrast point. The spectroelectrochemical behavior of the P(SNS-NH2-co-EDOT) compare to that of the homopolymer revealed solid evidence of copolymerization based upon the differences in the spectral signatures. Copolymer revealed multichromic property with five different colors at different applied potentials. Colorimetry studies for P(SNS-NH2-co-EDOT) proved that it is possible to provide fine tuning of these colors by varying applied potential during synthesis. The results of colorimetry, spectroelectrochemistry and FTIR studies showed the possible control of the color of the electrochromic material in a predictable, controlled and reproducible manner. As the last part of the study, dual-type complementary colored electrochromic devices (ECD) using P(SNS-NH2) and P(SNS-NH2-co-EDOT)/poly(3,4-ethylenedioxythiophene) (PEDOT) in sandwich configuration were constructed and evaluated. Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were investigated by UV-Vis Spectrophotometer and Cyclic Voltammetry. They have shown to possess good switching times, reasonable contrasts and high stabilities.

A new polythiophene derivative, poly-2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl)quinoxaline PHTQ was synthesized by both chemical and electrochemical polymerization and its electrochemical properties were reported. The monomer was electrochemically polymerized in the presence of tetrabutylammonium hexafluorophosphate(TBAPF6) as the supporting electrolyte in dichloromethane-acetonitrile (5:95, v:v). Nuclear magnetic resonance spectroscopy (1H-NMR, 13C-NMR) was utilized for the characterization of the monomer and the soluble polymer. The polymer was further characterized by Gel Permeation Chromatography (GPC). Spectroelectrochemistry and switching ability of the polymer were investigated by UV&ndash / vis spectrophotometer and cyclic voltammetry. The polymer revealed three distinctive colors upon doping which indicated that the polymer is multichromic. Tert-butyl group on the pendant phenyl rings and hexyl groups on thiophene enhanced the solution processability of the electrochromic polymer. The electrochemical and spectral properties of the chemically synthesized polymer were investigated via spray coating on ITO glass slides. Electrochemical copolymerization of 2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl) quinoxaline (HTQ) with 3,4-ethylenedioxythiophene(EDOT) was performed to fulfill a strategy in achieving fine-tuned electrochromic properties. The copolymer, P(HTQ-co-EDOT) was characterized via detailed studies of cyclic voltammetry and spectroelectrochemistry. Band gap (Eg) of the copolymer was calculated as 1.4 eV and showed 34 % optical contrast with switching times less than 1 second.

Organic semi-conductors are of great interest since these compounds can be utilized as active layers in many device applications such as ECDs, LEDs and solar cells. Incorporating the benzotriazole units into the polymer backbone enhances the optical properties of donor units. Hexyl thiophene and pyrrole are commonly used as electron donor materials. Benzotriazole can be coupled to hexyl thiophene or pyrrole to yield materials which can be polymerized to give donor acceptor type polymers. These materials are promising components in fast switching polymeric electrochromic devices and highly efficient photovoltaic devices. During thesis studies,poly(2-dodecyl-4,7-bis(4-hexylthiophen-2-yl)-2H-benzo[d][1,2,3]triazole) (PHTBT) and poly(2-dodecyl-4,7-di(1H-pyrrol-2-yl)- 2H- benzo [d] [1,2,3] triazole) (PPyBT) will be synthesized via N-alkylation, bromination, stannylation and Stille coupling reactions. Electrochromic and photovoltaic properties of the polymers will be investigated in detail.

Over the last decade, immobilization of proteins onto inorganic materials is becoming more crucial to extend a deep understanding of interaction between proteins and nanoparticles. With understanding of the real interaction lying under the protein-nanoparticle relations, it is possible to organize the conformation and orientation of surface and framework species of nanoparticles to generate ideal surfaces for potential biotechnological applications. Due to their unique properties such as large clean surface, tunable surface properties, adjustable surface charge, and dispersibility in aqueous solutions, zeolite and zeo-type materials are one of the remarkable classes of inorganic materials that are widely studied in the literature. These properties make zeolites promising alternative candidates for the immobilization of enzymes and incorporation into biosensing devices. In the current study, a new approach was developed for direct determination of urea, glucose, and butyrylcholine where zeolites were incorporated to the electrode surfaces of a conductometric biosensor and Ion Sensitive Field Effect Transistors were used to immobilize the enzymes. Biosensor responses, operational stabilities, and storage stabilities of the new approach were compared with results obtained from the standard membrane methods for the same measurements. For this purpose, different surface modification technique, which are simply named as Zeolite Modified Transducers (ZMTs) were compared with Standard Membrane Transducers (SMTs). During the conductometric measurements ZMT electrodes were used, which allowed the direct evaluation of the effect of zeolite morphology on the biosensor responses for the first time. It was seen that silicalite added electrodes lead to increased performances with respect to SMTs. As a result, the zeolite modified urea and glucose biosensors were successfully applied for detecting urea and glucose, which can offer improved possibilities to design biosensors. The results obtained show that zeolites could be used as alternatives for enzyme immobilization in conductometric biosensors development. Furthermore, the sensitivities of urease and butyrylcholinesterase biosensors, prepared by the incorporation of zeolite Beta crystals with varying acidity on the surface of pH-sensitive

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 recent years, environmental pollution becomes a health threatening issue for human beings. Technological developments introduce industrial wastes and heavy metals, and developments in agriculture introduce pesticides into the world that we live. All these toxic wastes accumulate in drinking water and food consumed by humans. Therefore, detection of toxic wastes in all kinds of environmental samples, and development of new detection techniques become an important issue. In this study, development of a protein-based biosensor for detection of heavy metals in environmental samples, by expressing genetically modified glutathione S-transferase (GST-(His)6) protein in E.Coli BL21 (DE3) expression system, was designed. Recombinant GST proteins was expressed in E.Coli BL21 (DE3) expression system and purified with Glutathione Sepharose 4B affinity column and Ni-NTA spin kit. GST activities were determined using the GST substrate 1-chloro-2,4-dinitrobenzene (CDNB). Protein expression was tested by SDS-PAGE and Western blot analysis. Product formation linearly increased up to 1 mM CDNB, 1 mM GSH, 1.7 &micro / g proteins in 0.05 M, pH 6.9 phosphate buffer in the final volume of 1.0 ml at 25&amp / #9702 / C. The Vmax and Km values for GST-(His)6 towards CDNB and GSH were calculated with Lineweaver-Burk as CDNB Vmax / 22.88 &micro / mol/min/mg, Km / 4.29 mM,and as GSH Vmax / 6.42 &micro / mol/min/mg, 24.45 &micro / mol/min/mg, Km / 3.69 mM, respectively. Biosensor working electrode was prepared by immobilizing the GST-(His)6 by 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC) coupling on the gold surface. Electrode preparation was confirmed by cyclic voltammetry measurements. The biosensor was inserted as the working electrode in the constructed three(four)-electrode flow cell. The conformational change resulting from the binding of the metal ions to the recombinant protein causing a capacitance change proportional to the concentration of the metal ions was determined. After the working electrode is standardized and calibrated, the heavy metal concentration in water samples was measured. The GST-(His)6 biosensor has a large operational range between 1 fM and 10 mM and a storage stability of approximately 2 weeks. The GST-(His)6 biosensor is very sensitive to, Cu+2&gt / Cd+2&gt / Zn+2&gt / Hg+2 metal ions, at low concentrations.

In this study three different 3-ester substituted thiophene monomers were synthesized via esterification reaction of 3-thiophene ethanol with adipoyl chloride or sebacoyl chloride or octanoyl chloride in the presence of triethylamine at 00C. Characterizations of the monomers were performed by 1H-NMR, 13C-NMR, FTIR, DSC, TGA techniques. Electrochemical behavior of the monomers both in presence or absence of BFEE were studied by cyclic voltammetry. Results showed the astonishing effect of BFEE on the polymerization, where free standing films of the homopolymers could be synthesized. Copolymers of the monomers with thiophene or 3-methyl thiophene were synthesized at constant potential electrolysis and the resultant polymers were characterized by FTIR, DSC, TGA, SEM and conductivity measurements. Second part of the study was devoted to investigate the one of most interesting property of conducting polymers, the ability to switch reversibly between the two states of different optical properties, &lsquo / electrochromism&rsquo / . In recent years there has been a growing interest in application of conducting polymers in electrochromic devices. Thus, electrochromic properties of the synthesized conducting polymers were investigated by several methods like spectroelectrochemistry, kinetic and colorimetry studies. Spectroelectrochemistry experiments were performed in order to investigate key properties of conjugated polymers such as band gap, maximum absorption wavelength, the intergap states that appear upon doping and evolution of polaron and bipolaron bands. Switching time and optical contrast of the homopolymers and copolymers were evaluated via kinetic studies. Results implied the possible use of these materials in electrochromic devices due to their satisfactory electrochromic properties like short switching time and stability. Generally the homopolymers displayed color changes between yellow, green and blue colors upon variation of applied potentials. Fine tuning of the colors of the polymers were accomplished by techniques like copolymerization and lamination. These studies were supported with experiments like spectroelectrochemistry and FTIR. Results showed the possible control of the color of the electrochromic material in a predictable, controlled and reproducible manner. Yet, it was possible to achieve different tones of yellow, green, orange color in neutral state of these materials. As the last part of the study, dual type electrochromic devices based on polymers of 3-ester substituted thiophenes with poly(3,4-ethylenedioxythiophene) were constructed, where the former and the later functioned as anodically and cathodically coloring layers respectively. Spectroelectrochemistry, switching ability, stability, open circuit memory and color of the devices were investigated and the results revealed that these devices have satisfactory electrochromic parameters.

A new neutral state green polymer, poly (2,3-bis(4-tert-butylphenyl)-5,8-di(1H-pyrrol-2-yl) quinoxaline) (PTBPPQ) was synthesized and its copolymer with bis(3,4-ethylenedioxythiophene) (BiEDOT) and 4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2-dodecyl-2H-benzo [1,2,3] triazole (BEBT) were produced. Finally polymers&rsquo / potential use as an electrochromic material was investigated. Electrochromic properties of the polymers were investigated by several methods including spectroelectrochemistry, kinetic and colorimetry studies. Key properties of conjugated polymers such as band gap, maximum absorption wavelength, the intergap states that appear upon doping and evolution of polaron and bipolaron bands were investigated via spectroelectrochemistry experiments. Switching times and optical contrasts of the homopolymer and the copolymer were evaluated via kinetic studies. Copolymer of TBPPQ with BiEDOT and BEBT were electrochemically synthesized and characterized. Resulting copolymer films have distinct electrochromic properties and revealed multichromism through the entire visible region. Although BiEDOT and BEBT have different oxidation potentials, the resulting copolymers have very similar redox behaviors. In a monomer free solution, both copolymers show four colors from purple, gray, light green to transmissive blue with the variation of the applied potential. Copolymerization with BiEDOT and BEBT not only decreases the band gap, Eg, but also enhances the electrochromic and optical properties. Hence, electrochemical copolymerization is considered to be a powerful tool to improve the electrochromic properties of quinoxaline derivatives. It should be noted that PTBPPQ is one of the few examples of neutral state green polymeric materials with superior switching properties. Hence, PTBPPQ can be used as a green polymeric material for display technologies.

Design of a monomer is a viable route for adjusting the properties of its corresponding polymer. The main goal of this study is to design and synthesize novel soluble polymers having various colors of color palette and amenable for use in electrochromic device applications. In designing the monomers, the factors affecting the properties of the polymers are also considered. For this purpose, each part of the monomers is chosen properly for each desirable properties and the effect of them is investigated separetely. Thus, this study is based on the investigation of the effect of three major parts on the polymer properties: Donor groups, acceptor groups and the length of alkyl chain. For this aim, nine D-A-D type monomers, TSeT, ESeE, PSeP-C10, PSP-C10, PNP-C10, POP-C10, PSeP-C4, PSP-C4 and PSP-C6, and their corresponding polymers, P(TSeT), P(ESeE), P(PSeP-C10), P(PSP-C10), P(PNP-C10), P(POP-C10), P(PSeP-C4), P(PSP-C4) and P(PSP-C6), based on thiophene, 3,4-ethylenedioxythiophene (EDOT), and 3,3-dialkyl-3,4-dihydro-2H-thieno[3,4-b]-[1,4]dioxepine (ProDOT-Cn) as D units and 2,1,3-benzoselenadiazole, 2,1,3-benzothiadiazole, 2-decyl-2H-benzo[d][1,2,3]triazole, and 2,1,3-benzooxadiazole as A units were synthesized. The obtained polymers have somewhat low band gap between 1.13 eV and 1.80 eV, they show electrochromic behaviors. Among them P(POP-C10), P(PSP-C10) and P(PSP-C6) have cyan color which is one leg of CMY (Cyan-Magenta-Yellow) color spaces. Since there have been scant studies on cyan colored polymers in the literature, these polymers are so precious. Via copolymerization of PNP-C10 and PSeP-C10, the first electrochemically synthesized neutral state black polymer was obtained.

A new class of &pi / -conjugated monomers was synthesized with combination of electron donating and electron-withdrawing heterocyclics to understand the effects of structural differences on electrochemical and optoelectronic properties of the resulting polymers. Electron deficient benzotriazole, substititued with benzyl from two available sites, coupled with stannylated electron donating groups, ethylenedioxythiophene (EDOT) and thiophene (Th), to yield four different monomers / 1-benzyl-4,7-di(thiophen-2-yl))-2H-benzo[d][1,2,3] triazole (BBTA), 2-benzyl-4,7-di(thiophen-2-yl))-2H-benzo[d][1,2,3] triazole (BBTS), 1-benzyl-4,7-bis(2,3-dihydrothieno[3,4-b]dioxin-5-yl)-2H-benzo [d][1,2,3]triazole (BBTEA), 2-benzyl-4,7-bis(2,3-dihydrothieno[3,4-b]dioxin-5-yl)-2H-benzo [d][1,2,3]triazole (BBTES). Furthermore, EDOT and thiophene terminated napthalene-2,3-crown ether containing monomers, 14,19-di(thiophen-2-yl)-naphtho[2,3-b][1,4,7,10,13] pentaoxacyclo pentadecane (TNCT), 14,19-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-naphtho[2,3-b][1,4,7,10,13]pentaoxacyclopenta decane (ENCE), were synthesized to observe the effect crown ether moiety on the final electrochemical and optoelectronic properties of resultant polymers. Cyclic voltammetry, UV-Vis-NIR spectroscopy and colorimetry techniques were employed to examine electrochemical and optoelectronic properties of all monomers and polymers. Experimental results showed that alteration of substituent, substitution position and donor groups&rsquo / strength lead to obtain polymers with different redox behaviors, optical band gaps and different number of achievable colored states.