Quartz crystal microbalance study of electrochemical deposition of poly(3-dodecylthiophene) films on Au electrodes (original) (raw)
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Electrochimica Acta, 2013
This work characterises the electropolymerisation of 3-methoxythiophene and presents an electrochemical study of poly(3-methoxythiophene) by cyclic voltammetry using different electrolytes in solvent mixture of water-acetonitrile (3:1, v/v) at 25 • C. Simultaneous measurements of the mirage effect and the quartz microbalance were also performed. This study evaluated the influence of cations on the electrochemical properties of monomers and polymers and allowed us to observe an anomalous behaviour of the synthesised polymer in the presence of potassium ions (K + ) when compared with other cations. The reversibility of the polymers was also evaluated with respect to the various electrolytes and was observed the influence of the polymer film thickness (deposited mass) on its electrochemical properties.
Electrochimica Acta, 2008
This paper shows that oligomers are retained inside the polymer film during the electrosynthesis of poly(3,4-ethylenedioxythiophene), PEDOT, in aqueous media. The behavior of the electrochemically generated PEDOT film is highly dependent on the presence of these oligomers. A detailed study of the release of oligomers trapped in the PEDOT film has been carried out using bidimensional spectroelectrochemistry (BSEC), spectroelectrochemical quartz crystal microbalance (SEQCM) and scanning electrochemical microscopy (SECM). These multiresponse techniques have allowed us to determine when these EDOT oligomers are released into solution and to investigate their electrochromic properties. Mass spectroscopy measurements revealed that most of these oligomers consist of four or six monomer units, which seem to be the most stable species in aqueous solution.
Electrochimica Acta, 2003
Poly(3,4-dialkoxythiophene) films with different length of alkyl chain (1,3 and 8 carbon atoms) were obtained on Pt and ITO electrodes from the monomer solutions in acetonitrile by cyclic voltammetry (CV). The properties of the resulting films were studied by electrochemical methods, UV Á/Vis, FTIR and NMR spectra. The CVs were correlated with differential cyclic voltabsorptograms (DCVA) recorded at the absorption maxima to explain the shape of the voltammograms of the polymers studied, dependent on the alkyl-chain length in alkoxy group. The presence of the zones of different crystallinity in the polymer film was postulated. Significant influence of the type of the solvent on asymmetry of the cyclic voltammograms for the polymer doping Á/undoping has been discussed in terms of the solvent interaction with radical cation (polaron) delocalized on the alkoxy side groups. The polaron delocalization was proved by 1 H-NMR spectra. Appearance of infrared activated vibrations (IRAVs) in the range 1500 Á/600 cm (1 and a characteristic electronic band at 3300 cm (1 at the polarization potential '/0.25 V versus Ag/Ag ' and their gradual changes upon further polymer oxidation were interpreted in terms of evolution of different charge carriers in lightly and heavily doped polymer.
Controlled Electrochemical Synthesis of Poly(3-octylthiophene) Considering Analytical Applications
Chemia analityczna
Poly(3-octylthiophene) was electrosynthesized galvanostatically and characterized electrochemically, by electrochemical quartz crystal microbalance and by in situ resonance Raman spectroscopy. Results from mass spectroscopy show that oligomers consisting of 3, 4, and 5 units were produced and trapped into the polymer film. H 1 NMR measurement confirmed the regioregular structure of these oligomers. The applied current densities (> 0.26 mA cm -2 ) during electrosynthesis played a predominant role on the content of regioregular oligomers in the film. Higher current densities were advantageous to the production of the oligomers; also lower monomer concentration (< 5 mmol L -1 ) promoted the formation of regioregular components. The thickness of the film was found to have minor influence on the content of the oligomers. Cyclic voltammograms of the formed films clearly show two well-separated pairs of reversible peaks representing two different charge transfer mechanisms, which can be derived from reduction/oxidation of the regioregular oligomers. The in situ Raman spectroscopic results show significant changes in the positions and intensities of the Raman bands upon oxidation.
Theoretical and Experimental Chemistry, 2010
An in situ spectroelectrochemical study was carried out on the formation of 3-methylthiophene oligomer radical-cations (monomer, dimer, and trimer) and the 3-methylthiophene dihydrocation in the solution bulk during the electrochemical synthesis of a poly-3-methylthiophene coating on a conducting glass electrode. A dependence of the concentration of products formed on the cation radius (Li + and Na + ) and nature of the anion (ClO 4 and BF 4 -) of the base electrolyte was established. The conversion of charged components into neutral dimers and tetramers of 3-methylthiophene after termination of the anodic polymerization was shown in accord with reported results on the electrochemical polymerization of thiophenes.
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, 1992
AIrstract-The small amplitude ac data of the poly(3octylthiophene) electrode-electrolyte system are analysed. The measurements are done at several & potentials for different thicknesses of the polymer fihn and for different electrolyte concentrations (lithium tetrafluoroborate in propylene carbonate). The Ladder type electrical circuit model is found to give best fit of the data. The high frequency double layer capacitance is shown to contain contributions from both sides of of the interface, ie the space charge layer of the polymer semiconductor and the Hehnholtx layer of the electrolyte. The experimental data are compared with calculated data by using a simple model of two capacitors in series, for a potential range including that where the reversible oxidation of the polymer takes place. The adsorption/surface state capacitance is shown to pass through a maximum and the corresponding coverage of surface species is determined. The structure of the double layer, the physical interpretation of the model parameters, and the energy level diagram for the polymer semiconductor electrode are proposed.
Electrochimica Acta, 2014
Electrochemical polymerisation of 3-octylthiophene and 4,4 -dioctyl-2,2 -bithiophene in acetonitrile is reported. The nature of the resultant films was investigated through electrochemical and spectroelectrochemical means, in concert with quantum mechanical calculations to evidence the oligomeric nature of the deposits. Control of conjugation length through solubility modification is demonstrated through investigation of UV-vis spectra of polymers prepared in different solvents. ESR-UV-vis-NIR spectroelectrochemical measurements were used to gauge the differences in the behaviour of regioregular and regiorandom deposits. Conjugation length was found to vary significantly between the two polymers. This is shown to influence the nature of charge carriers generated upon p-doping of the system.
Russian Journal of Electrochemistry, 2021
Methodology based on a combination of experimental data obtained by in situ methods of spectroelectrochemistry and electrochemical quartz crystal microbalance has been proposed for determination of the key parameters of the conjugated polymer deposition on the electrode surface via monomer electrooxidation. These parameters are: the current efficiency of the process, the charge spent per an oxidized monomer molecule, the number of monomer units inside the deposited film, and the average number of valence bonds per one monomer unit inside the film. Besides, the electrochemical quartz crystal microbalance method applied to the discharge process of the electropolymerized film allows determining the average charging (oxidation) degree of the monomer unit at the polymerization potential and the degree of the solvent participation in the polymer's redox transitions. The applicability of the proposed approach has been demonstrated by example of magnesium polyporphine films obtained by oxidation of unsubstituted magnesium porphine on inert electrode in acetonitrile solution at a low potential.