Copper modified poly(3,4-ethylenedioxythiophene (original) (raw)
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The Journal of Physical Chemistry, 1986
ESR studies of poly(3-methylthiophene) (PMeT) doped with S03CF3 anions and with various amounts of Cuz+ ions are reported. The S03CF3 doped PMeT has the characteristics of a metallic state: Dysonian line shape with a Pauli spin paramagnetism. When cathodically polarized in an aqueous copper solution, its conductivity increases by a factor of nearly 3 and is accompanied by an increase of the conduction electron spin resonance (CESR) line width. The features of the Cu2+ spectra depend on the cathodic polarization time. (i) For very short times (1 C t C 50 s), isolated Cu2+ ions in a strongly axially distorted octahedral environment are detected, with each ion surrounded by four water molecules and by two methylthiophene units (Cu2+(H20),(MeT),, complexation by sulfur atoms). This configuration leads to the bridging of the neighboring PMeT chains by the Cuz+ ions and consequently to the formation of a bidimensional system, which increases the interchain hopping rate. (ii) For a longer cathodic polarization time, Cu2+ clusters are formed which do not modify or affect either the ordering or the electrical properties of the polymer.
Journal of Polymer Research, 2006
Electrodeposition of poly(3,4-ethylenedioxythiophene) by electrochemical polymerization of 3,4-ethylenedioxythiophene has been performed on steel electrodes rather than on the typically used inert electrodes (Pt, Au, graphite carbon). The polymer was generated by cyclic voltammetry, chronopotentiometry and chronoamperometry from a 10 mM monomer solution in acetonitrile with 0.1 M LiClO4. Elemental analysis of the generated polymer indicated that the monomeric units support 0.54 positive charges balanced with CIO414− counterions. Electrochemical, electrical and structural properties of the prepared material have been characterized. The good adherence of films combined with its excellent properties indicate that poly(3,4-ethylenedioxythiophene) can be a suitable material for anticorrosion applications.
Electrochimica Acta, 2011
The electropolymerization of COOH-functionalized 3,4-ethylenedioxythipohene was investigated by cyclic voltammetry, by anodic potential steps or by flow of a constant anodic current. Compared with PEDOT, an anodic shift of the oxidation polymerization potential is observed. Nevertheless the polymer film oxidation/reduction is shifted to more cathodic potentials, giving higher stored specific charges than those obtained from PEDOT films generated in similar conditions. The generated polymer shows a stable redox process, E 0 = −0.04 V. EQCM results point to a p-doping process exchanging anions with solution, whereas a second reduction process at −0.77 V is related to a p-doping process exchanging cations. The new material is electrochromic: it is colourless in its oxidized state and blue colour in its reduced state. UV-Vis spectroelectrochemical results are similar to those obtained from PEDOT films.
Copper electrocrystallization in PEDOT in presence and absence of copper–polymer-stabilized species
Electrochimica Acta, 2005
Electrochemical reduction of copper ions in poly(3,4-ethylenedioxythiophene) (PEDOT), performed at low overpotential or low current density, allows for stabilization of Cu(I) species in the polymer layer. The electrocrystallization of copper at high overpotential is explored in absence and presence of pre-stabilized Cu(I) species in PEDOT. It is found that the copper-pre-stabilized material allows for a five-fold increase of the number of deposited copper crystals. Statistical analysis of the distances between neighbouring crystals shows for both (assynthesized and copper-pre-stabilized) materials a significant deviation from random Poisson probability distribution. For the first time, the experimental distributions are fitted by a theoretical probability model, accounting for the finite size of the crystals. The statistical analysis allows excluding the role of zones of reduced overpotential in the nucleation stage of electrocrystallization and concluding that new sites for nucleation become active in the presence of Cu(I)-stabilized species in PEDOT.
Solid State Ionics
Composite material combining electroactive polymer poly(3,4-ethylenedioxythiophene) (pEDOT) and inorganic redox particles of iron(II) hexacyanocobaltate(III) (FehcCo) was tested in contact with aqueous (KCl) and non-aqueous (LiClO4 in an ethylene carbonate:propylene carbonate solution) electrolytes. The pEDOT/FehcCo electrode layers were examined using electrochemical impedance spectroscopy, cyclic voltammetry and chronopotentiometry in the potential range of polymer activity and Faradaic activity of inorganic Fe3[Co(CN)6]2 redox network. The material pEDOT/FehcCo shows good stability and high electrical capacity (~70F cm−3 in a LiClO4 non-aqueous electrolyte). The electrode layers of pEDOT/FehcCo are porous and exhibit good adhesion to the electrode surface.
Materials Chemistry and Physics, 2012
The kinetics of electrochemical deposition of copper particles from Cu 2+ solution on platinum and poly-3methylthiophene modified platinum electrode was studied in potentiostatic conditions in presence of Cl − anions. The complex behavior of current transients suggests that the deposition process involves several stages with different kinetics. Results obtained on platinum show that after an initial adsorption process, the copper deposition is accomplished through two different models: a three-dimensional nucleation and growth under diffusive control (3DPD model) and a progressive nucleation and two-dimensional growth (2DP model). The analysis of current transients recorded on platinum poly-3-methylthiophene modified electrode (Pt/PMT) shows a very different behavior. On Pt modified electrode a process of growth related to a semi-infinite diffusion to a planar surface was accompanied by two different mechanisms of nucleation and growth: a three-dimensional nucleation and growth with no diffusive control (3DP model) and an instantaneous nucleation with two-dimensional growth (2DP model).
Synthetic Metals, 2000
. Ž . Electrochemical oxidation of poly 3,4-ethylenedioxythiophene PEDOT is investigated by cyclic voltammetry combined with ''in situ'' conductivity measurements, UV-vis-NIR and Raman spectroelectrochemical studies. The results seem to indicate that the doping can be adequately described by a heterogeneous ''two-phase'' model in which the doped conducting phase grows on the expense of the undoped, neutral phase. The extension of the scanning potential to 1400 mV vs. AgrAgCl leads to a finite potential window of PEDOT conductivity -the phenomenon reported for the first time in the case of PEDOT. The existence of this potential window can be rationalized within the framework of the ''two-phase'' model of electrochemical doping, assuming the coexistence of percolating conductive and insulating networks. Doping induced changes in Raman spectra of PEDOT indicate that, unlike in other polythiophenes, the ground state of the neutral polymer is quinoid in nature whereas upon doping it is transformed into the benzenoid one. q 2000 Elsevier Science S.A. All rights reserved.
Electrochemical Properties of Overoxidized Poly-3,4-Ethylenedioxythiophene
Russian Journal of Electrochemistry, 2018
The properties of poly(3,4-ethylenedioxythiophene) (PEDOT) films were studied electrochemically at high positive potentials (from-0.3 to 1.5 V relative to the Ag/AgCl electrode). A cyclic voltammetry (CV) study revealed the range of potentials (up to 1.3-1.5 V) where the cycling leads to significant changes in the electrochemical, structural, and morphological properties of the polymer film due to overoxidation. When the upper cycling potential E up exceeded 1.4 V, the anodic current significantly increased during the first cycle and then decreased, which suggests a loss of the electroactivity of the polymer and degradation of its properties. In the high-frequency region of the impedance spectra of the PEDOT films, a semicircle appears after overoxidation, which indicates a notable increase of the charge transfer resistance in the system, in contrast to the films subjected to potentiodymanic processing in a limited range of potentials from-0.3 to 1.3 V. The effect of overoxidation on the polymer morphology was studied by scanning electron microscopy. The chemical state of elements in the structure of the polymer film was determined by X-ray photoelectron spectroscopy. The obtained data indicate that-S=O groups formed at the thiophene sulfur in the polymer.
Functional Materials Letters, 2011
An electrochemical way to prepare poly(3,4-ethylenedioxythiophene) (pEDOT) modified by silver hexacyanoferrate (Aghcf) is presented. The electrode material is synthesized in two-stage procedure. The first stage is galvanic silver electrodeposition on a glassy carbon substrate electrode. The second step is silver stripping followed by Aghcf formation during monomer oxidation. Deposited composite layer is compact but not homogenous in a micro-scale. The low spin iron centre redox activity depends on a kind of the electrolyte. Potassium and nitrate ions are the most suitable for redox couple reversibility. The redox activity diminishes in contact with electrolytes in series KNO 3 > K 2 SO 4 > KBr. In the presence of chloride ions redox activity of silver hexacyanoferrate is inhibited. Spectroelectrochemical measurements proved electrochromic character of the film.