Taçlandırılmış iletken polimerlerin elektrokimyasal sentezi :

Poly(dibenzo-18-crown-6) (Poly(DB18C6)) was synthesized by electrochemical oxidation of dibenzo-18-crown-6 (DB18C6) using a mixture of acetonitrile and dichloromethane as solvent and tetrabutylammonium tetrafluoroborate (TBABF4) or tetrabutylammonium hexafluorophosphate (TBAPF6) as supporting electrolyte. The anodic polymerization of DB18C6 was investigated using in-situ ESR and in-situ UV-VIS spectroscopic techniques. Spectroelectrochemical (SPEL) properties and thermal analysis of the resulting polymers have been investigated using UV-VIS, Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). Furthermore, new compounds consisting of bis(2-thienyl) methyl (I and II) and bis(2-thienyl) ethyl (III) units linked by polyether bridges have been synthesized and their electrochemical polymerization was performed via constant potential electrolysis (CPE) in an electrolytic solution containing 0.1 M TBAPF6 dissolved in CH3CN. Also, I and II were polymerized via chemical oxidation which yielded broken ?-conjugated polymers except for III. The polymers were characterized using 1H-NMR and FT-IR spectroscopic techniques. In addition, copolymers of III with thiophene (Th) and pyrrole (Py) were studied with cyclic voltammetry (CV). SPEL behaviors of the products were investigated using UV-VIS spectroscopic technique.Ph.D. - Doctoral Progra

Designing a Solution Processable Poly(3,4-ethylenedioxyselenophene) Analogue

A new derivative (EDOS-POSS) of 3,4-ethylenedioxyselenophene integrated with alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) cage was synthesized and characterized. The electroactive monomer was successfully polymerized via both chemical and electrochemical methods. The obtained polymer called PEDOS-POSS was solution-processable and soluble in common organic solvents like tetrahydrofuran, toluene, dichloromethane, and chloroform. PEDOS-POSS polymer exhibited electrochromic behavior: pure blue when neutralized and highly transparent when oxidized. When compared to the parent PEDOS (1.40 eV with lambda(max) = 673 nm), PEDOS-POSS polymer film has a somewhat higher band gap (1.50 eV with lambda(max) = 668 and 724 nm). Also, PEDOS POSS exhibited high optical contrast ratio (59%) and coloration efficiency (593 cm(2)/C for 95% switching) with a low switching time (0.7 s) due to the presence of POSS cage in the polymer backbone. In addition, PEDOS-POSS polymer film was highly robust and stable under ambient conditions (without purging the electrolyte solution with inert gas). Polymer films demonstrated high electrochemical stability; for example, it retained 76% of its electroactivity after 5000 cycles. Furthermore, the polymers exhibited fluorescent properties and exhibited a reddish orange emission centered about at 640 nm. Based on the findings, to the best of our knowledge, it can be concluded that the polymers are the first examples of soluble and fluorescent PEDOS derivatives. These promising properties make PEDOS-POSS polymer a potential material for bioapplications like imaging the cancer cells as well as optoelectronic applications

Improvement of optical properties and redox stability of poly(3,4-ethylenedioxythiophene)

In order to improve the optical properties and redox stability of poly(3,4-ethylenedioxythiophene) (PEDOT) without changing its electrochemical and electrochromic behaviour, it was supported with alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) cage. The corresponding copolymers were obtained electrochemically via potentiostatic or potentiodynamic methods and compared to the parent homopolymers. Electrochemical polymerization of EDOT and POSS containing EDOT called EDOT-POSS in various monomer feed ratios was performed in an electrolyte solution of 0.1 M TBAPF(6) dissolved in a mixture of dichloromethane and acetonitrile (1/3: v/v). Just as PEDOT, the copolymers represented the similar band gap (1.61 eV), redox and electrochromic behaviors. On the other hand, when compared to the parent PEDOT, the presence of POSS cages in the copolymer backbone improved the redox stability and optical properties of PEDOT such as higher percent transmittance change (65% at 621 nm), higher transparency at oxidized state, lower switching time (similar to 1.0 s) and higher coloration efficiency (463 cm(2)/C for 95% switching) as well as higher electrochemical stability (86% of its electroactivity retains after 1750 cycles under ambient conditions)

Impedance spectroscopy of N-substituted oligo-oxyethylene polypyrrole films

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

Electrochemical copolymerization of thiophene containing pseudo-polyether cages with pyrrole

Conducting 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

Electrochemical synthesis of poly(3-bromo-4-methoxythiophene) and its device application

A functionalized thiophene containing both an electron withdrawing and an electron donating group, 3-bromo-4-methoxythiophene (BrMeOTh) was succesfully polymerized in acetonitrile containing 0.1 M tetrabutylammonium tetrafluoroborate (TBABF4) electrolyte via electrochemical oxidation of the corresponding monomer. BrMeOTh exhibits a lower oxidation potential (1.68 V vs Ag/AgCl) than thiophene (2.05 V vs Ag/AgCl). Spectroelectrochemical properties of poly(3-bromo-4-methoxythiophene) (PBrMeOTh) was investigated in situ recording the electronic absorption spectra of the polymer film coated on indium-tin oxide (ITO) at various potentials. The maximum transmittance difference between the oxidized and reduced states was measured as 39.2% and the time required to attain 90% of the total transmittance difference was found to be 1.2 s. Both cyclic voltammetric and spectroelectrochemical studies showed that the polymer exhibit a lower oxidation potential, a relatively narrow band gap, a stable conducting state and a higher degree of electrochemical reversibility. It is also found that, as synthesized PBrMeOTh films possess a linear structure along the polymer backbone. Moreover, dual type electrochromic device of PBrMeOTh with poly(3,4-diethylenedioxythiohene) (PEDOT) was constructed and its spectroelectrochemical, electrochromic switching and open circuit stability were investigated. Dual electrochromic device showed a good optical contrast and distinctive color changes with the ability of good switching times (1.1 s) under atmospheric pressure

A Platform to Synthesize a Soluble Poly(3,4-Ethylenedioxythiophene) Analogue

Alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) cage is combined with 3,4-ethylenedioxythiophene under the same roof. The corresponding monomer called EDOT-POSS is used to get soluble poly(3,4-ethylenedioxythiophene) (PEDOT-POSS) analogue. Both chemically and electrochemically obtained polymers are soluble in common organic solvents like dichloromethane, chloroform, tetrahydrofuran, and so forth. The PEDOT-POSS has somewhat higher band gap (1.71 eV at 618 nm) than its parent PEDOT (1.60 eV at 627 nm) and as expected the PEDOT-POSS exhibits higher optical contrast (74% at 618 nm) and coloration efficiency (582 cm(2)/C for 100% switching), lower switching time (0.9 s), higher electrochemical stability (93% of its electroactivity retains after 5000 cycles under ambient conditions) when compared to the PEDOT. A number of advantages of the PEDOT-POSS over the PEDOT can make it a promising material in the areas of electro-optical applications. (C) 2017 Wiley Periodicals, Inc