Polypyrrole electrosynthesis

Polypyrrole relatives obtained by electrosynthesis in the presence of different small inorganic or organic counter-ions that are interchanged with the electrolyte during electrochemical control of the material. 

The electrosynthesis of polythiophene (PT) from thiophene must be performed under extremely anhydrous conditions, quite in contrast to polypyrrole [334]. Polymerization of 3-methylthiophene and bithiophene is much less sensitive to water. The advantage of PT is a higher theoretical capacity and a very positive potential (cf. Table 7). It is for these reasons that its application as a positive electrode in rechargeable lithium batteries [335-338] and in a metal-free PPy/PT cell [339] has been considered. Derivatives such as dithienothiophene [340] or rra/is-l,2-di(2-thienyl)ethylene [341] have also been polymerized, but the polymer materials suffer from low theoretical capacities [337]. 

C.S.C. Bose and K. Rajeshwar, Efficient electrocatalyst assemblies for proton and oxygen reduction the electrosynthesis and characterization of polypyrrole films containing nanodis-persed platinum particles, J Electroanal. Chem., 333, 235-256 (1992). 

N. Cioffi, L. Torsi, L. Sabbatini, P.G. Zambonin, and T. Bleve-Zacheo, Electrosynthesis and characterization of nanostructiued palladium-polypyrrole composites, J. Electroarml. Chem., 488,42-47 (2000). 

Figure 16.10 OCP curves of coated PPy zinc electrodes cured In air for 1 h at 180 °C and immersed in 3.5% NaCI solution. PPy films (Ri2iim thick) were synthesized in 2 M NaSac+ 0.5 M Py at pH 5 and 1.9 M NaSac + 0.1 M DISacH + 0.5 M Py at pH 5.4. (Reprinted with permission from Chemistry of Materials, Ultrafast electrosynthesis of high hydrophobic polypyrrole coatings on a Zinc electrode Applications to the protection against Corrosion by E. Hermelin,]. Petitjean, P.C. Lacaze et al., 20, 13, 4447—4456. Copyright (2008) Elsevier Ltd)...

E. Hermelin, J. Petitjean, J.-C. Lacroix, K.I. Chane-Ching, J. Tanguy, and P.C. Lacaze, Ultrafast electrosynthesis of high hydrophobic polypyrrole coatings on a Zinc electrode Applications to the protection against Corrosion, Chem. Mater., 20, 4447 1456 (2008). 

Poly(pyrrole), known for over 50 years, is one of the most studied poly-mers. First synthesized by electrochemical polymerization in 1968, poly(pyrrole) is electrically conductive, stable, and insoluble when doped. The mechanism of its electrosynthesis was studied by Genies et Thin films of electropolymerized poly(pyrrole) (< 0.1 fim) are electroactive, and they can be switched between the neutral and the oxidized state at +0.1 V versus SCE. This particular property of polypyrrole can be applied in constructing conductivity... 

Ferreira, C.A., et al. 1996. Electrosynthesis of strongly adherent polypyrrole coatings on iron and mild steel in aqueous media. Electrochim Acta 41 1801. 

Jerome, C., D. Labaye, and I. Bodart. 1999. Electrosynthesis of polyacrylic polypyrrole composite Formation of polypyrrole wires. Synth Met 101 3. 

Jerome, C. Labaye, D. Bodart, 1. Jerome, R. Electrosynthesis of polyacrylic/polypyrrole composites formation of polypyrrole wires. Synth. Met. 1999,101, 3-4. 

The chemical synthesis and electrosynthesis of polypyrrole in the presence of sulfonated cyclodextrin as a dopant has been reported (52). In this case, cyclodextrin seems to play an important role in forming polymer with ordered structure. 

Electrosynthesis in Supercritical Fluids, Fig. 2 SEM photographs of polypyrrole films polymerized in (a) acetonitrile and (b) supercritical fluoroform solutions... 

Taouil AE, Lallemand E, Hihn JY, Blondeau-Patissier V (2011) Electrosynthesis and characterization of conducting polypyrrole elaborated under high frequency ultrasound irradiation. Ultrason Sonochem 18 907-910... 

In spite of all these advantages, the electrogeneration of polypyrrole is losing interest as a method for obtaining these materials. Alternative chemical methods of synthesis are being developed partly taking the place of electrosynthesis, even for such electrochemical... 

Region A corresponds to the behaviour of the dry acetonitrile solution. In these conditions, polypyrrole films are powdered and are low adherents. From elemental analysis it is observed that these films contain an important excess of hydrogen [46,54,133,134]. Moreover, electrosynthesis is accompanied by the simultaneous formation of a brown cloud of oligomers around the electrode [130]. As water is added, in region B, this cloud disappears and the electrical and mechanical properties of polypyrrole are strongly improved [128,130,135]. 

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