Conductive polymer polypyrrole

Figure 4 compares cyclic voltammograms for a redox polymer (poly-[Fe(5-amino-1,10-phenanthroline)3]3+/2+)91 and p-doping and undoping of a conducting polymer (polypyrrole).92 The voltammogram for the redox... 

Figure 4. (A) Cyclic voltammograms over a range of scan rates for a redox polymer (poly-[Fe 5-amino-1,10-phenanthrotme)3]3+/>)91 and (B) p-doping and undoping of a conducting polymer (polypyrrole) (B). [(A) Reprinted from X. Ren and P. O. Pickup, Strong dependence of the election hopping rate in poly-tris(5-amino-1,10-phenan-throline)iron(HI/II) on the nature of the counter-anion J. Electroanal. Chem. 365, 289-292,1994, with kind permission from Elsevier Sciences S.A.]...

The final step entailed coating both the inner and outer surfaces of the LiMn204 tubules with the conductive polymer polypyrrole [125]. It has been shown that such LiMn204/polypyrrole composite electrodes have lower resistance and higher capacity than electrodes prepared from LiMn204 alone [125]. Furthermore, the high porosity and fast (relative to... 

The deposition of a conductive polymer (polypyrrole) into either a track-etched polycarbonate or alumina membrane was either achieved by electrochemical reduc-... 

More recent studies have focussed on the characterization of the conductive polymer, polypyrrole, and its use as a coating for acoustic wave vapor sensors [74-77]. One advantage of polypyrrole is that it can be generated directly on an... 

Ramanavicius, A., Ramanaviciene, A., Malinauskas, A. (2006). Electrochemical sensors based on conducting polymer-polypyrrole. Electrochim. Acta 51 6025-37. 

An optically active and electroconductive polymeric sorbent was prepared by coating the PS-L-proline-Cu(II) beads with conducting polymer polypyrrole. Applying a potential difference of 1.5 V to the column, racemic lysine and aspartic acid were separated according to their charge characteristics and were simultaneously resolved with respect to their optical isomerism. 

An interesting application is photosensitized polymerization of pyrrole (431) using [Ru(bpy)3]3 + to give a conducting polymer, polypyrrole (432), in aqueous solution or in a polymer matrix (Scheme 6.205).1236 The acting ground-state electron acceptor, [Ru(bpy)3]3 +, is obtained in the initial electron transfer step between an excited [Ru(bpy)3]2+ and [Co(NH3)5C1]2+ ion. 

Aizawa has studied an enzyme (metal) electrode based on immobilized GOD, which is a redox enzyme [66]. Interfacing in this type of biosensor requires facilitation of electron transfer from the active site of the enzyme protein to the metal electrode. Various methods have been used, such as electron mediators, electron promoters, and molecular wires, to accomplish this purpose. For example, a conducting polymer, polypyrrole, formed by electropolymerization on the electrode surface, was used to form electron wires which can facilitate electron transfers to and from the metal electrode. 

Figure 14-18. Covalent binding of enzymes to the conducting polymer polypyrrole. The reaction sequence shows the functionalization of the electrochemically deposited polymer film by nitration and subsequent electrochemical reduction.

The principle is to activate molecular oxygen, by the Mn porphyrin entrapped in the conductive polymer (polypyrrole), and thus to form oxo species at the electrode surface. Then, these oxo complexes can oxidize the hydrocarbons or phenol. The catalyst should be regenerated and this can be done by electroreduction at a constant potential (typically at — 0.5 V/SCE in acetonitrile). Moreover, the solution should contain an axial base (i.e. imidazole), and an activator (benzoic anhydride) [165,172]. 

The bandgap of an intrinsically conducting polymer (polypyrrole) has been determined with photocurrent spectra [749]. 

A. Ramanaviciene, W. Schuhmann, and R. Ramanavicius, AFM study of conducting polymer polypyrrole nanoparticles formed by redox enzyme - glucose oxidase - initiated polymerisation, Colloid Surf. B., 48(2), 159-166 (2006). 

K. Yamato and K. Kaneto, Tubular linear actuators using conducting polymer, polypyrrole. Anal. Chim. Acta, 568 (1-2), 133-137 (2006). 

X. Cui, J.F. Hetke, J.A. Wiler, D.J. Anderson, and D.C. Martin, Electrochemical deposition and characterization of conducting polymer polypyrrole/pss on multichannel neural probes. Sens. Actual. A Phys., 93(1), 8-18 (2001). 

Poly 1 -(trimethylsilyl)-1 -propynel Conjugated conducting polymers Polypyrrole Polythiophene... 

Wadhwa, R., Lagenaur, C.F., Cui, X.T., 2006. ElectrochemicaUy controlled release of dexamethasone from conducting polymer polypyrrole coated electrode. J. Controlled Release 110,531-541. 

Hao, L., Zhu, C., Chen, C., Kang, E, Hu,Y., Fan, W., Chen, Z., 2003. Fabrication of silica core-conductive polymer polypyrrole shell composite particles and polypyrrole capsule on monodispersed silica templates. Synth. Met. 139,391-396. 

Apart from electrochemical routes, polypyrrole can also be synthesized by simple chemical ways to obtain powders. Basically chemical oxidative polymerization methods can be used to synthesize bulk quantities of polypyrrole in a fast and easy way. Like other conducting polymers polypyrrole exhibit more limited environmental, thermal and chemical stability than conventional inert polymer due to the presence of dopant and its dynamic and electro active nature. 

Imprinted polymers exhibiting, at the same time, electrical conductivity facilitate their assembly with an electrochemical transducer in an integrated device. In this context, the preparation of composite particles consisting of an electrically conducting polymer (polypyrrole) and an acrylic MIP should be mentioned [42]. The polypyrrole that was grown into the preformed porous MIP did not alter its recognition properties. However, in this way MIP particles could be mechanically and electrically connected to a gold-covered silica substrate. 

Figure 10.1. The mostly used conducting polymers polypyrrole (a), polyaniline (b], and pol5d hiophene (c].

Nguyen Thi H. Le, B. Garcia, C. Deslouis, Le Q. Xuan, Corrosion Protection and Conducting Polymers Polypyrrole Films on Iron. Electrochim. Acta 2001,46,4259-4272. 

Sixou, B., N. Mermilliod, and J.P. Travers. 1996. Aging effects on the transport properties in conducting polymer polypyrrole. Phys Rev B 53 4509. 

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