Electrochemical copolymerization of N-methylpyrrole and 2,2 '-bithitiophene; characterization, micro-capacitor study, and equivalent circuit model evaluation

N-methylpyrrole (N-MPy) and 2,2'-bithiophene (BTh) were electrocopolymerized in 0 center dot 2 M acetonitrile-sodium perchlorate solvent-electrolyte couple on a glassy carbon electrode (GCE) by cyclic voltammetry (CV). The resulting homopolymers and copolymers in different initial feed ratios of [N-MPy](0)/[BTh](0) = 1/1, 1/2, 1/5 and 1/10 were characterized by CV, Fourier-transform infrared reflectance attenuated transmittance (FTIR-ATR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and electrochemical impedance spectroscopy (EIS). The capacitive behaviours of the modified electrodes were defined via Nyquist, Bode-magnitude, Bode-phase and admittance plots. The equivalent circuit model of R(C(R)(QR)(CR)) was performed to fit theoretical and experimental data. The highest low-frequency capacitance (C (LF)) were obtained as C (LF) = similar to 1 center dot 23 x 10 (-4) mF cm (-2) for P(N-MPy), C (LF) = similar to 2 center dot 09 x 10 (-4) mF cm(-2) for P(BTh) and C (LF) = similar to 5 center dot 54 x 10 (-4) mF cm(-2) for copolymer in the inital feed ratio of [N-MPy](0)/[BTh] (0) = 1/2.Research Foundation of Namik Kemal University, TurkeyNamik Kemal University [NKUBAP.00.10.YL.12.02]Financial support for this work by the Research Foundation of Namik Kemal University, Turkey, (project number: NKUBAP.00.10.YL.12.02), is gratefully acknowledged

Metallic Glass Films with Nanostructured Periodic Density Fluctuations Supported on Si/SiO2 as an Efficient Hydrogen Sorber.

Nanostructured metallic glass films (NMGF) can exhibit surface and intrinsic effects that give rise to unique physical and chemical properties. Here, a facile synthesis and electrochemical, structural, and morphologic characterization of Pd-Au-Si based MGs of approximately 50 nm thickness supported on Si/SiO2 is reported. Impressively, the maximum total hydrogen charge stored in the Pd-Au-Si nanofilm is equal to that in polycrystalline Pd films with 1 μm thickness in 0.1 m H2 SO4 electrolyte. The same NMGF has a volumetric desorption charge that is more than eight times and 25 % higher than that of polycrystalline PdNF and Pd-Cu-Si NMGF with the same thickness supported on Si/SiO2 , respectively. A significant number of nanovoids originating from PdHx crystals, and an increase in the average interatomic spacing is detected in Pd-Au-Si NMGF by high-resolution TEM. Such a high amount of hydrogen sorption is linked to the unique density fluctuations without any chemical segregation exclusively observed for this NMGF

Micro-Capacitor Behavior of Poly(3-Hexyl Thiophene)/Carbon Fiber/Electrolyte System and Equivalent Circuit Model

In this article, 3-Hexyl thiophene (3HTh) monomer was electrocoated on carbon fiber micro electrode (CFME) to study electrochemical impedance spectroscopic (EIS) analysis. Poly(3HTh)/CFME is characterized by Cyclic voltammetry (CV), Fourier transform infrared reflectance-attenuated total reflection spectroscopy (FTIR-ATR), Scanning electron microscopy-Energy Dispersive X-ray analysis (SEM-EDX), and electrochemical impedance spectroscopy (EIS). The effects of different monomer concentrations (0.5, 1.0 and 1.5mM) on polymer were reported in 0.1M tetraethyl ammonium tetrafluoroborate (TEABF4)/acetonitrile (ACN) solution. The highest low frequency capacitance (C-LF = 1.394 mF cm(-2)) was obtained for [3HTh](0) = 0.5mM. The equivalent circuit model of R(QR(CR)(RW))(CR) was examined for polymer/electrolyte system.Research Foundation of Namik Kemal UniversityNamik Kemal University [NKU.BAP.00.10.AR.11.01]This work was supported by the Research Foundation of Namik Kemal University (Project No. (NKU.BAP.00.10.AR.11.01). The authors thank Ozlem Oskan (Afyon Kocatepe University, Technology and Research Center (TUAM), Afyon, Turkey) for recording the SEM-EDX point analysis. The authors also thank to Prof. Dr. A. Sezai Sarac for the usage of the Electropol Laboratory at Istanbul Technical University, Istanbul, Turkey

Electrolyte effects of poly(3-methylthiophene) via PET/ITO and synthesis of 5-(3,6-di(thiophene-2-yl)-9H-carbazole-9-yl) pentanitrile on electrochemical impedance spectroscopy

In this article, 3-methylthiophene (3MTh) and 5-(3,6-di(thiophene-2-yl)-9H-carbazole-9-yl) pentanitrile (ThCzpN) comonomer were electrochemically deposited on poly(ethylene terephthalate)/indium tin oxide (PET/ITO) electrode and carbon fiber micro electrode (CFME) in sodium perchlorate (NaClO4)/acetonitrile (ACN), respectively. ThCzpN comonomer was characterized by 1H-nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy (FTIR) analysis. Poly(ThCzpN)/CFME is characterized by cyclic voltammetry (CV), Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), and electrochemical impedance spectroscopy (EIS). The detailed characterization of the resulting electrocoated poly(3MTh) on PET/ITO thin films was studied by different techniques, i.e., CV and EIS. The effects of electrolytes after electrocoated of modified electrodes were examined by EIS technique in various electrolytes medium (sodium perchlorate (NaClO4), lithium perchlorate (LiClO4), tetraethyl ammonium tetrafluoroborate (TEABF4), and tetrabutyl ammonium tetrafluoroborate (TBABF4)/acetonitrile (ACN) solution). Capacitive behaviors of modified PET/ITO electrode were defined via Nyquist, Bode-magnitude, Bode-Phase, and admittance plots. Variation of capacitance values by various electrolytes and low-frequency capacitance (CLF) values are presented. CLF value electrocoated polymer thin film by CV method in the 0.1M NaClO4 electrolyte with a charge of 7.898 mC was obtained about 59.1 mF cm-2. The highest low-frequency capacitance (CLF) was obtained from the Nyquist plot with [ThCzpN]0 = 3 mM as 0.070 mF cm-2. Equivalent circuit model [R(QR(CR)(RW))(CR)] was suggested for poly(3MTh) on PET/ITO in four different electrolytes medium. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012Research Foundation of Namik Kemal UniversityNamik Kemal University [NKU.BAP.00.10.AR.11.01]; Scientific & Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG-110T516]Contract grant sponsor: Research Foundation of Namik Kemal University; contract grant number: NKU.BAP.00.10.AR.11.01.; Contract grant sponsor: Scientific & Technological Research Council of Turkey (TUBITAK); contract grant number: TBAG-110T516

Covalent Immobilization of Urease on Poly(Pyrrole-3-carboxylic Acid): Electrochemical Impedance and Mott Schottky Study

Pyrrole-3-carboxylic acid was electropolymerized on a glassy carbon electrode in 0.1 M NaClO4/ACN, Et4NBF4/ACN using cyclic voltammetry. Urease (Urs) was immobilized onto PPCA modified GCE via covalent binding, exploiting EDC/NHS chemistry. Electrochemical impedance spectroscopy was used to investigate the interfacial behavior of Urs immobilized PPCA surfaces at open circuit potential. The impedance spectra were fitted before and after immobilization of Urs using equivalent circuits of R(C(R(Q(RW)))). After immobilization of Urs onto the PPCA matrix, the charge transfer resistance (R-CT) increased for electrodes, which R-CT of urease immobilized PPCA-NaClO4 matrixes were lower than that of the Urs immobilized PPCA-Et4NBF4 matrixes indicating higher charge transfer ability. A decrease in double layer capacitance (C-dl) values when Urs was immobilized at the PPCA-NaClO4 electrode surface was observed, whereas an increase at the PPCA-Et4NBF4 electrode surface was observed. Urs immobilized electrodes resulted in a n-type semiconducting behavior revealing a positive slope. An increase in acceptor concentration of the electrodes, and a shift of the E-FB to more positive values with increasing amount of urease was observed. The Urs based electrode (PPCA-NaClO4-Urs) was used for detection of urea, which was detected in range of 0.9 to 14 mM with a detection limit (LOD) of 8.28 mu M. (C) 2016 The Electrochemical Society. All rights reserved.Scientific & Technological Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [214Z200]This work was supported by The Scientific & Technological Council of Turkey (TUBITAK)-214Z200 Project

Mott-Schottky and Morphologic Analysis of Poly(Pyrrole-N-Propionic Acid) in various electrolyte systems

In this study, pyrrole-N-propionic acid (PPA) was electrochemically polymerized on a glassy carbon electrode (GCE) in various electrolytes (NaClO4, Et4NBF4, Bu4NClO4, and Bu4NPF6) using cyclic voltammetry (CV). The structure and morphology of the modified electrode was characterized by FTIR-ATR, visible-near-infrared spectroscopy (Vis-NIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The morphological characterizations of the poly(PPA) films synthesized in the various supporting electrolyte solutions were demonstrated by SEM and AFM. Electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) analysis were performed to collect information about the semiconducting properties of the poly(PPA) films. From the Mott-Schottky analysis, the carrier densities (N-D) of the poly(PPA) films obtained were 3.25x10(16),1.59x10(16), 1.17x10(16), and 0.52x10(16) cm(-3), and the flat-band potentials were 0.41, 0.32, 0.37, and 0.36 V for the poly(PPA)films in NaClO4, Et4NBF4, Bu4NClO4, Bu4NPF6, respectively. The resulting Mott-Schottky plots of the poly(PPA) films indicate that the films are p-type semiconductors. EIS analysis were performed to determine the capacitive behaviors by variation of electrolyte types in a monomer-free solution. An equivalent-circuit model of R(W(CR)(QR))(CR) was used to fit the theoretical and experimental data to interpret the polymer electrode/electrolyte interface properties and to provide information about equivalent circuit parameters.Scientific & Technological Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [214Z200]This work was supported by The Scientific & Technological Council of Turkey (TUBITAK)-214Z200 Project

A novel synthesis of (3,6-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-9-(4-vinylbenzyl)-9H-carbazole), alternating polymer formation, characterization, and capacitance measurements

In this work, (3,6-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-9-(4-vinylbenzyl)-9H-carbazole) (EDOTVBCz) comonomer was chemically synthesized and characterized by Fourier transform infrared (FTIR), proton nuclear magnetic resonance, and carbon nuclear magnetic resonance spectroscopy. EDOTVBCz was electrocoated on glassy carbon electrode (GCE) in various initial molar concentrations ([EDOTVBCz](0) = 1.0, 1.5, 2.0, and 3.0) in 0.1 M lithium perchlorate (LiClO4)/acetonitrile (CH3CN). P(EDOTVBCz)/GCE was characterized by cyclic voltammetry, FTIR reflectance-attenuated total reflection spectroscopy, scanning electron microscopy-energy dispersive X-ray analysis, atomic force microscopy, and electrochemical impedance spectroscopy (EIS). EIS was used to determine the capacitive behaviors of modified GCE via Nyquist, Bode magnitude, Bode phase, and admittance plots. The highest low-frequency capacitance value was obtained as C (LF) = similar to 2.35 mF cm(-2) for [EDOTVBCz](0) = 3.0 mM. Double-layer capacitance of the polymer/electrolyte system was calculated as C (dl) = similar to 2.78 mF cm(-2) for [EDOTVBCz](0) = 1.0 and 3.0 mM. The maximum phase angle was obtained as theta = similar to 76.7(o) for [EDOTVBCz](0) = 1.0, 1.5, 2.0, and 3.0 mM at the frequency of 20.6 Hz. AC impedance spectra of P(EDOTVBCz)/LiClO4/CH3CN was obtained by performing electrical equivalent circuit model of R(Q(R(CR))) with linear Kramers-Kronig test.Scientific & Technological Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG-110T791]This work supported by The Scientific & Technological Council of Turkey (TUBITAK)-TBAG-110T791 Project

Supercapacitor Behavior of Poly(Carbazole-EDOT) Derivatives/Multi-Walled Carbon Nanotubes, Characterizations and Equivalent Circuit Model Evaluations

Three new different comonomers of carbazole-EDOT derivatives had been previously synthesized and characterized in detail. In this study, electroactive materials were electropolymerized onto multi-walled carbon nanotube (MWCNT) modified glassy carbon (GC) electrode in 0.1M sodium dodecyl sulphate (SDS) solution. The electrochemical impedance spectroscopic results of Nyquist, and Bode-magnitude and Bode-phase plots show that polymers/MWCNT composites possess good capacitive characteristics. P(Com2)/MWCNT/GCE system's specific capacitance was up to Sc=132.6Fg(-1) at the scan rate of 70mVs(-1) from the area formula, Eq. (1). Furthermore, P(Com2)/MWCNT composite had very rapid charge/discharge ability with specific capacitance of Sc=75.23Fg(-1) at DC potential of 0.3V from Nyquist plot, and Sc=90.53Fg(-1) at the scan rate of 60mVs(-1) from charge formula, Eq. (2), which is important practical advantage. In addition, such composite had a good cycling performance and a wide potential window. Long-term stability of the capacitor was also tested by CV, and the results indicated that, after 500cycles, the specific capacitance was still at approximate to 100.0%, approximate to 89%, and approximate to 97.0% of the initial capacitance for P(Com1)/MWCNT, P(Com2)/MWCNT, and P(Com3)/MWCNT, respectively. An equivalent circuit model of R-s(C-1(R-1(Q(R2W))))(CGCRGC) was obtained to fit the experimental and theoretical data. Solution resistance (Rs) and resistance from GCE decrease gradually. However, capacitance of film (C-1), constant phase element (Q), and n values increase for P(Com1), P(Com2), and P(Com3)/MWCNT, respectively. Therefore, more homogeneous and less rough surface composite film was obtained by addition of MWCNT in the composite material.Scientific & Technological Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG-110T791]This work was supported by The Scientific & Technological Council of Turkey (TUBITAK)-TBAG-110T791 Project

Copolymer formation of 9-(2-(benzyloxy)ethyl)-9H-carbazole and 1-tosyl-1H-pyrrole coated on glassy carbon electrode and electrochemical impedance spectroscopy

In this work, 9-(2-(benzyloxy)ethyl)-9H-carbazole (BzOCz) and 1-tosyl-1H-pyrrole (TsP) monomers were chemically synthesized and characterized by Fourier transform infrared reflectance (FTIR) and proton nuclear magnetic resonance (H-1-NMR) spectroscopy. BzOCz and TsP were electrocoated on glassy carbon electrode (GCE) in various molar fractions (X (TsP) = 0.5, 0.83, 0.91, and 0.98) in 0.1 M sodium perchlorate/acetonitrile. The detailed characterization of poly(BzOCz-co-TsP) was studied by cyclic voltammetry, FTIR-attenuated total reflection spectroscopy and electrochemical impedance spectroscopy (EIS). The effects of different molar fractions during the preparation of modified electrodes were studied by EIS technique. The AC impedance technique was used to determine the capacitive behaviors of modified GCE via Nyquist, Bode magnitude, and Bode phase plots. The highest low frequency capacitance value was obtained as C (LF) = 23.94 mu F cm(-2) for X (TsP) = 0.98. Therefore, synthesized copolymer has more capacitive behavior than its homopolymers, such as C (LF) = 7.5 mu F cm(-2) for poly(BzOCz) and C (LF) = 9.44 mu F cm(-2) for poly(TsP). In order to interpret the AC impedance spectra, R(Q(RW)) electrical equivalent circuit was employed with linear Kramers-Kronig test. A mechanism for electropolymerization has been proposed for copolymer formation