Browsing by Author "Onal, A. M."
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Article Citation Count: 11NEW EDOT CONTAINING POLYMERS: EFFECT OF RING SIZE ON THE BENZIMIDAZOLE ACCEPTOR(Pergamon-elsevier Science Ltd, 2016) Cihaner, Atilla; Onal, A. M.; Cihaner, A.; Chemical EngineeringIn this study, three different benzimidazole (BIm) based acceptor groups bearing cyclohexane, cycloheptane and cyclooctane rings at 2-C position of benzimidazole were synthesized and coupled with ethylenedioxythiophene (EDOT) donor units via Stille cross-coupling reaction. The resulting donor acceptor-donor (DAD) type monomers were examined in terms of their electrochemical and optical behaviors. All three monomers exhibited dual absorption bands due to their donor-acceptor pattern and exhibited one irreversible oxidation peak at about 0.80 V. The monomers were electrochemically polymerized via both potentiostatic and potentiodynamic methods and electro-optical properties of obtained conjugated polymer films were investigated in monomer free electrolytic solution. It was found that the polymer films exhibited quasi-reversible redox behavior due to the doping/dedoping process of the polymers, which was accompanied by a reversible electrochromic behavior. Electrochromic investigations showed that all three polymer films showed similar multichromic behaviors: green in the neutral state, gray in the oxidized state, and brick-red in the reduced state. Their band gap (Eg) values were elucidated utilizing spectroelectrochemical data and it was found to be around 1.18 eV. Furthermore, one of the polymer film was utilized for the construction of transmissive type electrochromic device (ECD) with poly(3,4-ethylenedioxythiophene) (PEDOT). (C) 2015 Elsevier Ltd. All rights reserved.Article Citation Count: 9Propylenedioxy and Benzimidazole Based Electrochromic Polymers(Electrochemical Soc inc, 2016) Cihaner, Atilla; Onal, A. M.; Cihaner, A.; Chemical EngineeringIn this study, three acceptor units were synthesized by substituting cyclohexane, cycloheptane and cyclooctane rings at 2-C position of benzimidazole. These acceptor units were coupled with dihexyl substituted 3,4-propylenedioxythiophene (PRODOT-C6) donor segments and the resulting donor-acceptor-donor monomers were polymerized via potentiostatic and potentiodynamic methods to obtain their corresponding conjugated polymers (CP). Monomers and their polymers were investigated in terms of the ring size of the substituent on the acceptor unit and their electrochemical and optical behaviors were reported. The monomers exhibited dual absorption bands (at about 310 nm and 520 nm) due to their donor-acceptor pattern. CP films on indium tin oxide conducting substrate were investigated in a monomer free electrolytic solution. The polymer films exhibited quasi-reversible redox behavior due to doping/dedoping which was accompanied by a reversible electrochromic behavior. All three polymer films showed similar multichromic behaviors: green color in the neutral state, gray in the oxidized state, and brick-red in the reduced state. Band gap values (E-g) were elucidated via both electrochemical and optical methods. Moreover, electrochromic device (ECD) was constructed with one of the polymer films (cyclohexane ring bearing benzimidazole and PRODOT-C6 containing polymer) with poly(3,4-ethylenedioxythiophene) (PEDOT). (C) 2016 The Electrochemical Society. All rights reserved.Article Citation Count: 7Synthesis and Electrochemical Polymerization of Dithienosilole-Based Monomers Bearing Different Donor Units(Electrochemical Soc inc, 2016) Cansu, Emine Gül; Ergun, E. G. Cansu; Onal, A. M.; Chemical EngineeringThree new donor-acceptor-donor (DAD) type monomers containing five membered heteroaromatic rings as the donor units and the silicon-bridged bithiophene as the acceptor unit were synthesized via Stille cross-coupling reaction. The monomers, 2,6-di(furan-2-yl)-4,4-dioctyl-4H-silolo[3,2-b:4,5-b'] dithiophene (FSiF), 4,4-dioctyl-2,6-di(thiophen-2-yl)-4H-silolo[3,2-b:4,5-b']dithiophene (TSiT) and 4,4-dioctyl-2,6-di(selenophen-2-yl)-4H-silolo[3,2-b:4,5-b'] dithiophene (SeSiSe) were polymerized electrochemically via potential cycling in acetonitrile-tetrabutylammonium perchlorate electrolytic medium. Optical and electrochemical properties of the monomers and their corresponding polymers were investigated and it was found that oxidation potentials of the monomers and optical properties of both monomers and their polymers showed slight variations depending on the heteroatom present in the donor unit. (C) 2016 The Electrochemical Society.