Polyaniline electrodes

Croissant MJ, Nappom T, Leger J-M, Lamy C. 1998. Electrocatal3tiic oxidation of hydrogen at platinum-modified polyaniline electrodes. Electrochim Acta 43 2447-2457. 

In potentiometric sensors, an electrical potential between the working electrode and a reference electrode is measured at zero current conditions in a solution containing ions that exchange with the surface. The first potentiometric MIP sensor was prepared in 1992 by Vinokurov (1992). The substrate-selective polyaniline electrode was electrosynthesized with polypyrrole, polyaniline, and aniline-p-aminophenol copolymers. The development of an MIP-based potentiometric sensor was reported in 1995 by Hutchins and Bachas (1995). This potentiometric sensor has high selectivity for nitrite with a low detection limit of (2 + l)x 10 M (Fig. 15.10). 

A few other types of anion sensors have been mentioned recently in the literature. Tetrathiofulvalene microcrystals immobilised at a platinum electrode displayed electrochemical properties that were affected by the presence of anions in solution, with some selectivity for anions such as bromide [ 145]. A flow-injection analysis system using anion-exchange columns for separation and polyaniline electrodes as detectors could detect dichromate down to 0.004 ppb and could be used for seawater samples [146]. 

A battery cell where both the electrodes consist of dopable polymer is shown in Figure 5.23. The electrolyte in this case consists of Li+ClO 4 dissolved in an inert organic solvent, usually tetrahydro-furan or propylene carbonate. When two sheets of polyacetylene or PPP are separated by an insulating film of polycarbonate saturated in an electrolyte (lithium perchlorate), and completely encapsulated in a plastic casing, a plastic battery can be made. The two sheets of polyacetylene or PPP act as both anode and cathode for the battery. A schematic is shown in Figure 5.24. Although doped polyacetylene and polyaniline electrodes have been developed, polypyrrole-salt films are the most promising for practical appKcation. 

F. Ficicioglu and F. Kadirgan, Electrooxidation of ethylene glycol on a platinum doped polyaniline electrode, J. Electroanal. Chem., 451, 95 99 (1998). 

A.M. Castro-Luna, Novel electrocatalytic polyaniline electrode for methanol oxidation, J. Appl. Electrochem., 30, 1137-1142 (2000). 

Fig. 24 Variation of EQCM resonant frequency with simultaneously ellipsometrically determined film thickness during deposition of polyaniline. Electrode Ron 5-M Hz AT-cut quartz crystal. Solution ...

Grace AN, Pandian K (2006) Pt, Pt-Pd and Pt-Pd/Ru nanoparticles entrapped polyaniline electrodes - a potent electrocatalyst towards the oxidation of glycerol. Electrochem Conunun 8 1340-1348... 

It has been recently revealed that it is possible to fabricate all vacuum deposited metal (Pb, Al, In, Sn)/polyaniline/metal Schottky devices [101]. It has been shown that the barrier height and the ideality factors determined are dependent on the work function of the metal used in the fabrication of these devices. The improved ideality factor obtained as 1.2 for an Al/polyaniline/Ag device has been attributed to more intimate contact of the metal with the vacuum deposited polyaniline electrode. 

Boschi, T, et al. 1988. Behaviour of polyaniline electrodes in aqueous and organic solutions. / Power Sources 24 185. 

Ryu, K.S., et al. 2002. Symmetric redox supercapacitor with conducting polyaniline electrodes. 7 Power Sources 103 305. 

Table 5.6 Characteristics of electrochemically synthesized polyaniline (Electrode 1 cm, Charge of synthesis 14 mA h)...

Figure 15.7 Cyclic voltammograms for a polyaniline electrode of an electrochemical capacitor cycled in 3 M NaCI04 -E 1 M HCIO4 before and after 20 000 cycles 148]. Reprinted from D. Belanger, X. Ren, J. Davey, F. Uribe and S. Cottesfeld, Characterization and long-term performance of polyaniline-based electrochemical capacitors, J. Electrochem. Soc., 147, 2923-2929 (2000), with permission from the Electrochemical Society...

A polyaniline nanojunction switch has been bricated by creating a bridge across gaps between nanometer scale polyaniline electrodes. When briging is indicated by a short circuit, the junction can be characterized as a function of applied potential. Abrupt switching fi om insulator to conductor is seen at about 0.15 V vs Ag/AgCl that is explained on the bases of st changes in domains of strands (35). 

Koleli, F., Ropke, D., Aydin, R., Rdpke, T. (2011). Investigation of N2-fixation on polyaniline electrodes in methanol by electrochemical impedance spectroscopy. Journal of Applied Electrochemistry, 4/(4), 405—413. 

Polyaniline forms stable, coherent films when grown electrochemically. Scanning electron microscopy pictures reveal that the film surfaces are fairly smooth [148]. After exposure and handling in air, the films maintain their electrochemical properties and can drive redox reactions such as the oxidation of ferrocene to ferricinium. When the pH of a solution containing a polyaniline electrode is increased above 3, a marked decrease in the electroactivity of the polymer occurs. 

Dhawale DS, Vinu A, Lokhande CD (2011) Stable nanostructured polyaniline electrode for... 

J. Ye and R. P. Baldwin, Flow injection analysis of electroinactive anions at a polyaniline electrode. Anal. Chem. 60 1979 (1988). 

Guo Z, Li S, Liu XM, Gao YP, Zhang WW, Ding XP (2011) Mesoporous carbrui-polyaniline electrode characterization and application to determination of copper and lead by anodic stripping voltammetry. Mater Chem Phys 128 238-242... 

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