Electrochemical and Spectroelectrochemical Characterization of Some Polypyrrole/Anthraquinone Sulfonate Films

Abstract

Conducting polymer films incorporating electroactive species have been used for sensor applications, and the redox properties have been utilized in charge-storage devices such as super-capacitors and batteries. [1][2][3][4][5][6] The optical properties associated with redox switching in some conducting polymers have been studied for possible use in electrochromic devices with high coloration efficiencies.7-14 Polypyrrole (PPy) is one of the most useful conducting materials, since it polymerizes easily, forms a membrane readily and has high conductivity and chemical stability. [15][16][17] Moreover, since it is easy to combine PPy with other anionic molecules, many functional composites with various properties have been investigated. [18][19][20] Especially, the PPy/quinone film is of analytical importance for the application in electrocatalysis and enzyme sensors. [21][22][23] In connection with our study, charge transfer of pyrrole copolymers substituted by anthraquinone, phenothiazine, or anthracene moieties has been reported. [24][25][26] The electrical conductance of PPy films doping with various anthraquinone and naphthalene sulfonates appears to be very well correlated to the number of sulfonate groups attached, with the highest conductance attained at one sulfonate group per dopant molecule. [27][28][29] Hepel has shown that the electrochemical quartz crystal microbalance (EQCM) technique can be used successfully to examine the doping level and the ion transport rate. 30In this research, we prepared several composite films consisting of polypyrrole and quinone sulfonates in aqueous solution by using electropolymerization techniques. FTIR spectral measurements and elemental analysis of PPy/9,10-anthraquinone-2-sulfonate (AQS -) revealed that the quinone sulfonates were incorporated in the polypyrrole matrix. Cyclic voltammetry and spectroelectrochemistry indicated the formation of diand trianions of AQS -during the reduction of the film. Further, it was found that the PPy/AQS -could function as a cation-exchanger at electrode potentials below about -0.3 V vs. Ag/AgCl. Experimental MaterialsPyrrole (Wako Chemicals Co.) was used without further purification. All quinones used here were reagent grade and were purified by vacuum sublimation or recrystallization when impurities were found in voltammograms. Tetraethylammonium perchlorate (TEAP) was dried in a vacuum and stored over P 2 O 5 . Milli-Q water was used throughout our experiments. Reagent grade dimethylsulfoxide (DMSO) and dimethylformamide (DMF) were used as received from Wako Chemicals. Equipment and proceduresGlassy carbon (GC) electrodes (Tokai, grade GC-20, diameter 3 mm) were polished with fine alumina (60 mm) and then sonicated for 5 min. Gold plated semitransparent plastic films (FM-1 Courtaulds Performance Films, USA, 1.75 cm 2 ) were used as We have fabricated composite films of polypyrrole/quinone sulfonate via electropolymerization. The FTIR investigation indicated the incorporation of quinone sulfonate in the polypyrrole (PPy) film to com...

Differential pulse polarographic determination of poly(8-hydroxyquinoline) in the presence and absence of an insulating poly(vinyl alcohol) matrix

“…We have previously investigated the complexation of 8-hydroxyquinoline-5-sulfonyl hydrazide with metal ions [22,23,24] and recently found that electrical conductivity, electroactivity, and spectroelectroactivity could be induced in poly(o-toluidine) and/or polypyrrole emeraldine base form after doping [25,26,27,28,29].…”

Thermal degradation studies of poly(o-anisidine) doped with 5-sulfosalicylic acid

“…Poly(o-anisidine) doped with hydrochloric acid (HCl-doped POAN) was prepared following the previously described procedure [32][33][34]. The oxidation of o-AN in strong acid medium (HCl, 1.5 mol l −1 ) produces a radical cation, which can react with further molecule to give predominantly paralinked dimeric radical.…”

“…The problem of thermal stability of homo-and hetero-chain linear polymers has important applications [25][26][27]. In our previous work, we have found that the electrical conductivity, electroactivity, spectroelectroactivity or thermal stability could be induced into some polymeric forms [28][29][30][31][32][33][34][35][36][37].…”

Electroactivity of Polypyrrole Colloids Enhanced by Quinone Mediation

“…A pyrrole vs. AQS Ϫ ratio of 3:1 has been suggested for polypyrrole/AQS Ϫ films, 21,22 and a relative doping level of 78% (4:1) was calculated for our particles from results of elemental analysis. Perchlorate added on polymerization would occupy the rest of the position.…”

“…21 Elemental analysis of PPyPVA(AQS Ϫ ) also indicated the inclusion of AQS Ϫ (percent found for sulfur, 4.0%). Consequently, we can safely conclude from the results of TG-MS, FT-IR, and elemental analysis that the PPyPVA particle was doped with AQS Ϫ and was highly hydrophilic.…”