Electrochemically-Obtained Polysulfonic-Acids Doped Polyaniline Films—A Comparative Study by Electrochemical, Microgravimetric and XPS Methods (original) (raw)
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Acid Doping of Polyaniline: Spectroscopic and Electrochemical Studies
The Journal of Physical Chemistry B, 1999
A detailed investigation of the acid doping behavior of polyaniline has led to a robust and reproducible procedure for controlled adjustment of the redox state of dry polyaniline films. The initial step in this procedure is the casting of PANI films from formic acid. The subsequent exchange of the trapped formic acid for other primary dopants obtained from mono-and polyprotic acids (e.g., CH 3 COO-, BF 4-, HSO 4-, SO 4 2-, H 2 PO 4-, and HPO 4 2-) is demonstrated. The voltammetric and the spectroscopic behavior of the PANI doped with different anions indicate that both the protons and the anions of dopant acids influence the structure and redox properties of the polymer. The redox state of PANI doped with homologous series of chloroacetic and carboxylic acids correlates with the pK a of the dopant acid. These results show that it is possible to prepare the polymer with a desired oxidation state according to the pK a of the dopant acid of a given homologous series. The exchange of the formic acid for both stronger and weaker doping acid can be repeatedly accomplished by electrochemical cycling.
Electrochemical characteristics of polyaniline synthesized in the presence of ferrocenesulfonic acid
Synthetic Metals, 2002
Ferrocenesulfonic acid plays an important role in increasing the electrochemical polymerization rate of aniline. Polyaniline (PAnFc) prepared in the presence of ferrocenesulfonic acid has a rather high electrochemical activity at pH ! 4 compared with polyaniline (PAn) prepared in the absence of ferrocenesulfonic acid. The cyclic voltammograms of both PAn and PAnFc in 0.5 mol dm À3 Na 2 SO 4 with pH ! 4 show that the low electrochemical activities are caused by the low electron transfer ability of both polymers themselves. The study on the temperature dependence of the cyclic voltammograms at pH 5.0 indicates that there are two anodic peaks and two cathodic peaks for PAnFc, however, there are only one anodic peak and one cathodic peak for PAn at the temperature <60 8C in the potential range between À0.2 and 0.6 V (vs. SCE). Based on the results from the constant current discharge of polyaniline batteries, the capacity density and energy density of PAnFc are 124.0 A h kg À1 and 126.2 W h kg À1 , respectively, which are 1.58 and 1.47 times higher than the capacity density and energy density, respectively, of PAn. The FTIR spectrum of PAnFc is presented here. #
Korean Journal of Chemical Engineering, 2002
In this study, the polyaniline films of emeraldine base(EB) and lucoemeraldine base(LEB) form chemically doping with poly(sodium-4 styrenesulfonate, PSS) were prepared by casting the mixed solution of chloroform and m-cresol on ITO(indium tin oxide) electrode. By analyzing UV-vis spectra of the mixed solutions, the effects of the secondary doping by mcresol were obtained. And the conductivity of polyaniline film was increased with increasing m-cresol content. The results suggest that the improvement of conductivity obtained by secondary doping results primarily from interaction of polyaniline and m-cresol. As the results of analyzing cyclic voltammograms, it was known that the redox peak currents of polyaniline electrode prepared from LEB were larger and more reversible than those of polyaniline electrodes prepared from EB. The charge transfer resistances(R ct) of polyaniline electrodes were reduced with increasing m-cresol content, and LEB/PSS electrodes were smaller than EB/PSS electrodes. This result agrees to the analysis of the redox peak current of cyclic voltammograms. The solution resistance and the capacity of electrical double layer almost unchanged in all prepared polyaniline electrodes. It was confirmed that solution resistance was independent of frequency factor in AC impedance spectra. Also the polyaniline film doping with PSS was revealed pseudo n-type characteristics of conducting polymer.
Polyaniline Thin Film Prepared by Electrochemical Polymerization Method
Biointerface Research in Applied Chemistry, 2021
Polyaniline (PANI) slim film was set up by electrochemical polymerization strategy at room temperature in a standard three-electrode cell from (0.1M) aniline monomer and (0,5M) from Sulfuric acid in the presence of distilled water. The development of PANI film was portrayed by Voltammetric studies, SEM, XRD, and FTIR. Voltammetric studies were performed in 0.5 M acidic aqueous solutions using H2SO4. The XRD design demonstrated that the diffraction top at 2θ = (30˚). The FTIR spectroscopy spectra give particular and unmistakable bonds at 3500, 1572.52, 1302.53, 831.98, and 592.85 cm-1.
Influence of Dopant on Electroactivity of Polyaniline
Polyaniline (PANI) films were polymerized on glass carbon (GC) electrodes with small molecular dopantshydrochloric, perchloric, sulfuric, methanesulfonic, benzenesulfonic, rtoluenesulfonic and large macromolecular size poly(4-styrenesulfonic (PSS)), poly(vinylsulfonic), poly(acrylic), and poly(anilinesulfonic) acids.Theredox electroactiveswere studied in buffered solutions with the pH of 3, 5, 7, and 9. Results indicated that the properties PANI films were strongly dependent on the molecular size and polar characteristics of the dopants. With the polyelectrolytes, it was found that the PANI doped with PSS showed a good redox behavior, and maintained the inherent electro activity of PANI in the neutral and even in alkaline media.
Comparison of Chemically and Electrochemically Prepared Polyaniline. Films. 1. Electrical Properties
Chemistry of Materials, 1995
Relaxation phenomena in thin polyaniline films synthesized chemically and electrochemically are investigated by UV-vis and IR spectroscopy. It is shown that the relaxation process carried out from the electrochemically oxidized or electrochemically reduced states of the polyaniline always proceeds toward the emeraldine state. The relaxation process in acid is governed by disproportionation and formation of semiquinone radicals. The changes in the population density of the polaronic states within the polaronic band allows determination of the change in the oxidation state and consequently the change in the position of the Fermi energy level. The formation of polaronic states is ascertained by diffusion of ions from or into t h e polyaniline matrix in solution and
Morphology and electrical properties of hybrid and sulphonated oxalic acid-doped polyaniline
Synthetic Metals, 2010
Polyaniline-polyethylene glycol2000 (PAni-PEG2000) hybrid and sulphonated polyaniline (SPAni) were prepared using oxalic acid as dopant and potassium permanganate as oxidant. The properties of these two conductive polymers were studied in comparison with pure polyaniline (PAni) prepared using the same conditions. The investigated polymers were characterized using FTIR, UV-vis, TGA, TEM, SEM, XRD and their electrical conductivities were also investigated. The morphology of pure polymer was found to be flat ribbon-like form, while presence of polyethylene glycol led to the formation of separate nanospheres. The three polymer samples have different degrees of crystallinity, the highest degree is for SPAni. Unexpectedly, electrical conductivity is in the order SPAni > PAni-PEG2000 > PAni, aging of PAni increases gradually the conductivity of the polymer from 0.0056 to 0.023 S cm −1 and the increase of temperature gradually decreases the conductivity.
Effect of temperature on the electrochemical synthesis and properties of polyaniline films
Journal of Non-Crystalline Solids, 2010
The effect of temperature on the electrochemical oxidative polymerization of aniline and on the electrochemical properties of the resulting polyaniline (PANI) film was studied. The electrochemical deposition of PANI has been carried out on platinum at different temperatures. Three different films (PANI-25, PANI-40 and PANI-60) have been prepared at 25, 40 and 60°C by electrochemical polymerization and characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Increasing the synthesis temperature leads to an increase of the polyaniline films thickness from 0.4 to 0.9 lm and, respectively, 1.1 lm, associated with an increase of the films capacitances from 3 Â 10 À2 F cm À2 to 7 Â 10 À2 F cm À2 and 10 Â 10 À2 F cm À2 . The impedance measurements showed that only PANI-25 and PANI-40 exist in the conductive state over a large potential window, while PANI-60 has an intermediate behavior at low and high electrode potentials.
Study of the Electrical Characteristics of Polyaniline Prepeared by Electrochemical Polymerization
Energy Procedia, 2012
Polyaniline (PAni) is one of imported polymer for synthesis solar cells .The quality of film depended on the method of polymerization. In this research PAni have been prepared by the electrochemical polymerization of aniline on stainless steel electrode. The electrical conductivity of these films was measured by two-probe method .The electrical conductivity is influenced by preparation conduction such as concentration of H 2 SO 4 and current density .The conductivity between (0.1 -10 -10 ) S/cm depends on PH and current density . The best electrical conductivity about (0.1) S/cm was found PH at (4.2) and current density 0.3mA/cm2.
Langmuir, 2000
Sulfonated polyaniline (SPAN) films were studied using simultaneous potentiodynamic, ellipsometric, spectroelectrochemical, and quartz crystal microbalance experiments. Ellipsometric experiments show that there is a small variation of film thickness (∼2%) between the reduced and oxidized states. The role of ionic transport during the redox reaction is emphasized in order to obtain information about all chemical species involved in the process occurring in the conducting polymer film. Quartz crystal microbalance results show the relevant participation of cations in the charge compensation process. The spectroelectrochemical study shows spectral changes accompanying the oxidation/reduction process of SPAN as the increase/diminution of the polaron band at 400 nm and another band at higher wavelengths as a function of potential. These changes were shown to be reversible.