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Article Citation - WoS: 2Citation - Scopus: 3Impedance Spectroscopy of N-Substituted Oligo-Oxyethylene Polypyrrole Films(John Wiley & Sons inc, 2008) Cihaner, Atilla; Onal, Ahmet M.The electrochemical properties of neutral (dedoped) and oxidized (doped) poly(1,11-bis(1,1-pyrrole)-3,6,9-trioxaundecane) (poly-I) film electrodes were investigated using cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques. Poly-I was deposited on glassy carbon electrode (GCE) from acetonitrile solution containing 5.0 x 10(-3) M 1,11-bis(1,1-pyrrole)-3,6,9-trioxaundecane (I) and 0.1 M LiClO4 supporting electrolyte. Doped poly-I exhibits a single semicircle in its complex-capacitance plots, indicating a single dominant ion transport process, together with high capacitance values. These features make this polymer film a candidate for an energy storage material. Also, poly-I can be a candidate as a sensory material for the detection of Ag+ based on impedance parameters. (C) 2008 Wiley Periodicals, Inc.Article Citation - WoS: 6Citation - Scopus: 6Side Chain Effect on the Electrochemical and Optical Properties of Thieno[3,4-c]pyrrole-4,6-dione Based Donor-Acceptor Donor Type Monomers and Polymers(Royal Soc Chemistry, 2023) Cakal, Deniz; Arabaci, Elif Demir; Yildirim, Erol; Cihaner, Atilla; Onal, Ahmet M.In organic pi-conjugated materials, side chains play great roles that impact far beyond solubility. In this work, we mainly focused on the synthesis of new donor-acceptor-donor (D-A-D) type conjugated monomers and their corresponding polymers appending thieno[3,4-c]pyrrole-4,6-dione (TPD) acceptor with a new side chain, fluorene (Fl), to investigate the side chain effect. In this context, to reveal the precise effect of the side chains on the optical and electrochemical properties of the monomers and polymers synthesized in this work, four series of D-A-D monomers, each containing a TPD core unit with a different side chain, are compared and discussed in relation to each other. Notably, it was discovered that the TPD acceptor unit can be modified with any functional group other than common alkyl chains to impart new functionalities by maintaining their superior optoelectronic properties. New types of side chains can be used to tune the physical characteristics, such as solubility, absorption, emission, and molecular packing. In this work, Fl-appended monomers as a new class of D-A-D type pi-conjugated molecules containing 3,4-ethylenedioxythiophene (EDOT (E)) and 3,4-propylenedioxythiophene (ProDOT (P)) donor units were studied and it was found that 1,3-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-5-(9H-fluoren-2-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (E(Fl)) and 1,3-bis(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-5-(9H-fluoren-2-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (P(Fl)) exhibited reasonable quantum yields and their corresponding polymers revealed ambipolar character with slightly lower band gap as compared to the previous analogues containing other side chains. Observed experimental results were elucidated by first principle calculations. In this paper, we discussed that using side chain engineering is an effective strategy for improving next-generation organic pi-conjugated materials with the desired properties.Article Citation - WoS: 7Citation - Scopus: 7Electrochemical and optical properties of dicyclohexylmethyl substituted poly(3,4-propylenedioxythiophene) analogue(Wiley, 2018) Cakal, Deniz; Cihaner, Atilla; Onal, Ahmet M.An analogue of disubstituted 3,4-propylenedioxythiophenes, namely 3,3-bis(cyclohexylmethyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin (ProDOT-CycHex(2)), was synthesized and its electrochemical polymerization was carried out successfully in an electrolyte solution of 0.1 M tetrabutylammonium hexafluorophosphate dissolved in a mixture of acetonitrile and dichloromethane (3/1: v/v). The corresponding polymer called PProDOT-CycHex(2) has a reduced band gap of 1.85 eV and an electrochromic property: blue/violet when neutralized and highly transparent when oxidized. Also, PProDOT-CycHex(2) film exhibited faster response time (0.7 s) and higher coloration efficiency (769 cm(2)/C) during oxidation when compared to its benzyl substituted analogue. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46214.Article Citation - WoS: 14Citation - Scopus: 16Electrosynthesis of Polyfuran in Acetonitrile-Boron Trifluoride-Ethyl Ether Mixture and Its Device Application(John Wiley & Sons inc, 2007) Tirkes, Seha; Onal, Ahmet M.Electrochemical polymerization of furan was achieved in acetonitrile/boron trifluoride/ethyl ether (CH3 CN/BF3/EE) mixture in the presence of tetrabutylammonium tetrafluoroborate via constant potential electrolysis at 1.4 V versus Ag/AgCl. Electrochemical behavior of furan was investigated in the same solvent mixture of varying ratios, utilizing cyclic voltammetry. Free-standing polyfuran (PFu) films were obtained in CH3CN/BF3/EE mixture (2/4/4; v/v/v) and characterized using FTIR spectroscopic technique. Spectroelectrochemical behavior of the PFu film was investigated by recording the electronic absorption spectra, in sitn, in monomer-free solution. It is observed that PFu film can be reversibly cycled between -0.1 V (gray) and + 0.6 V versus Ag-wire (gray color); however, this behavior diminishes in the presence of water. Electrochromic device application of PFu film with poly(ethylene dioxythiophene) was also studied. (c) 2006 Wiley Periodicals, Inc.Article Citation - WoS: 6Citation - Scopus: 6Electrochemical Copolymerization and Characterization of Dianilines Linked by Polyether Bridge With Aniline(Springer, 2010) Tirkes, Seha; Onal, Ahmet M.Copolymer of aniline and triethylene glycol bis(o-aminophenyl) ether was synthesized by constant potential electrolysis. Cyclic voltammogram of the copolymer films recorded in the monomer-free electrolytic solution revealed that the redox behavior of the films approaches to that of poly(triethylene glycol bis(o-aminophenyl) ether) with increasing amount of triethylene glycol bis(o-aminophenyl) in the feed ratio. Copolymerization was investigated by in situ recording the changes in the electronic absorption spectrum during electrolysis. The free standing copolymer film was characterized utilizing Fourier transform infrared spectrometer, and spectroelectrochemical behavior of the copolymer was investigated via in situ UV-vis spectroscopic technique. Besides the electron spin resonance study of the copolymer film, the different morphologies of the polymers were examined by scanning electron microscopy and the copolymerization was confirmed. The temperature dependence conductivity of the copolymer film was measured by four-probe technique in the temperature range of 100-300 K, and the calculated parameters showed that conduction mechanism fits to variable range hopping.Article Citation - WoS: 94Citation - Scopus: 100A New Soluble Neutral State Black Electrochromic Copolymer Via a Donor-Acceptor Approach(Elsevier, 2010) Icli, Merve; Pamuk, Melek; Algi, Fatih; Onal, Ahmet M.; Cihaner, AtillaTwo donor-acceptor systems, 2-decyl-4,7-bis(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-2H-benzo[d][1,2,3]triazole (1) and 4,7-bis(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-2,1,3-benzoselenadiazole (2) are explored in order to attain a low bandgap black polymer electrochrome, which is highly difficult to attain due to the complexity of designing such materials. Electrochemical polymerization of 1 and 2 in 1:4 monomer feed ratio was performed in a mixture of acetonitrile and dichloromethane solution containing 0.1 M tetrabutylammonium hexafluorophosphate. It was found that electropolymerization provides a processable neutral state black copolymer, (P(1-co-2)), which absorbs virtually the whole visible spectrum (400-800 nm). (P(1-co-2)) is the first low bandgap (1.45 eV) electropolymerized material, which switches from black color (L = 14.3, a = 0.29, b = 0.35) in the neutral state to transmissive grey (L = 39.2, a = 0.29, b = 0.33) in the oxidized state with 15.3% of the transmittance change at 522 nm. Furthermore, it exhibits excellent operational and/or environmental stability under ambient conditions. (c) 2010 Elsevier B.V. All rights reserved.Article Citation - WoS: 2Synthesis of n-polyethereal Polypyrroles and Their Application for the Preconcentration of Rare Earth Ions(John Wiley & Sons inc, 2008) Koksel, Bahar; Cihaner, Atilla; Kaya, Murat; Volkan, Muervet; Onal, Ahmet M.Conducting polymers containing polyether pseudocages (PI, PII, PIII) have been synthesized via chemical oxidation of 1,5-bis(1,1-pyrrole)-3-oxabutane (MI), 1,8-bis(I,I-pyrrole)-3,6-dioxahexane (MII), and 1,11-bis(1,1-pyrrole)-3,6,9-trioxaundecane (MIII) using anhydrous FeCl3 in CHCl3. Because as obtained polymer resins did not give any response toward any cations, they were reduced (undoped) using chemical reducing agents. Tetrabutylammonium hydroxide was found to be more effective in undoping to obtain more reproducible and reusable polymer resins. The undoped polymer resins were tried in the extraction of rare earth metal ions from the aqueous medium. Among them, only PIII resin removes La(III), Eu(III) and Yb(III) and can be employed for the preconcentration of these metal ions. For batch extraction of La(III), Eu(III) and Yb(III) at neutral pH values, percent recoveries of 98.0 +/- 1.0, 90.7 +/- 1.4, 87.3 +/- 4.0, respectively, has been obtained. The sorption capacity is found as 1.3 mg of La(III) per gram of PIII resin. The PIII resin could be reused at least five times without significant change in its sorption capacity. (c) 2008 Wiley Periodicals, Inc.Article Citation - WoS: 26Citation - Scopus: 30Electrochemical Polymerization of 9-Fluorenecarboxylic Acid and Its Electrochromic Device Application(Elsevier Science Sa, 2008) Bezgin, Buket; Cihaner, Atilla; Onal, Ahmet M.Poly(9-fluorenecarboxylic acid) (PFCA) was synthesized by electrochemical oxidation of 9-fluorenecarboxylic acid (FCA) using a mixture of nitromethane and boron trifluoride diethyl etherate as the solvent and tetrabutylammonium tetrafluoroborate as the supporting electrolyte. An insoluble and conducting brownish-orange film was deposited on the electrode surface, both during repetitive cycling and constant potential electrolysis at 1.15 V. Characterization of the polymer film has been carried out using Fourier Transform Infrared spectroscopy technique and thermal behavior was studied via thermal gravimetric analysis. Structural analysis showed that the polymerization of FCA occurred at 2,7-position. Spectroelectrochemical behavior of the polymer film on indium tin oxide working electrode was studied by recording the electronic absorption spectra, in-situ, in monomer-free electrolytic solution at different potentials and it is found that the PFCA film can be reversibly cycled between 0.0 V and 1.2 V Furthermore, a dual type electrochromic device based on PFCA was constructed and its spectroelectrochemical properties were investigated. The electrochromic device exhibits color change from transparent to dark blue with a good open circuit memory. (c) 2008 Elsevier B.V. All rights reserved.Article Citation - Scopus: 1Electrochemical Copolymerization of Thiophene Containing Pseudo-Polyether Cages With Pyrrole(Tubitak Scientific & Technological Research Council Turkey, 2006) Cihaner, Atilla; Onal, Ahmet M.; Chemical EngineeringConducting copolymers were synthesized via the electrochemical oxidation of pyrrole (Py) in the presence of the monomer 1,12-bis(2-thienyl)-2,5,8,11-tetraoxadodecane (1). The presence of monomer I in the electrolytic solution greatly changed the CV behavior of Py during its potensiodynamic polymerization. The electroactivity of poly(I-co-Py) increased with the increasing amount of I in the comonomer mixture. Copolymer films were prepared via constant potential electrolysis in an electrolytic solution containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF(6)) dissolved in acetonitrile. The spectroelectrochemical properties of the films were investigated using UV-VIS spectroscopy.Article Citation - WoS: 27Citation - Scopus: 31Donor-acceptor polymer electrochromes with cyan color: Effect of alkyl chain length on doping processes(Elsevier, 2012) Celikbilek, Ozden; Icli-Ozkut, Merve; Algi, Fatih; Onal, Ahmet M.; Cihaner, AtillaA new series of donor-acceptor-donor (D-A-D) type compounds consisting of dialkyl substituted 3,4-propylenedioxythiophene and benzothiadiazole units were synthesized and polymerized chemically and electrochemically to investigate the effect of alkyl chain length on the doping process of the conjugated polymers. It was found that the alkyl chain length plays a key role on both doping processes and the solubility of the polymer. It is also noteworthy that this new series of D-A-D electrochromes transmits or reflects the cyan color of the Cyan-Magenta-Yellow (CMY) color space in the neutral state which can be switched to transmissive grey when oxidized. (C) 2011 Elsevier B.V. All rights reserved.
