Doping intrinsically conducting polymers

Intrinsically conducting polymers are a broad class of (often) processable materials based upon doped -it conjugated polymers. Their conductivities vary from that of insultators through to that of semiconductors and even good metals. A wide variety of electronic phenomena are observed. Because of the broad choice of materials and properties, this class of polymer is potentially of use in a large number of technologies. 

Polymeric tubes for clad lead-acid battery plates have been made from intrinsically conductive polymers [19] by weaving fibres of polypyrrole, poly(phenylene vinylene), or polythiophene of several hundred microns in thickness. Polyaniline [20] as well as polypyrrole, polyparaphenylene, and polyacetylene doped with anions (C104, FeCl, AsFj, sol", and HSO4) have also been added as 1.15pm powders or fibres to positive pastes to improve capacity [21]. 

The research of the conductivity phenomena of the new materials category of the class of intrinsically conductive polymers proceeded from the paradigm that the transport phenomena were linked to the properties of the polymer chain. This began with the hypothesis that polyacetylene was an ideal candidate for the search for solitons. The oxidation, which was incorrectly called doping , of the chain of the original non-conductive polymer made possible a kind of folding over of the conjugated double bonds, thereby the flow of electrons was set in motion and the intrinsical conductive polymer was bom. 

In order to render a plastic conductive although it is, by nature, an electrical and thermal insulator (with the exception of intrinsically conducting polymers, ICPs), we need to dope it with electrically conductive fillers such as steel microfibers (pFSs) [FEL 06], CNPs [FEL 01] or indeed carbon nanotubes [FEL 11]. By gradually varying the proportion of fillers in the polymer matrix, we see that its resistance goes... 

The first conducting polymers (named ICPs for intrinsically conducting polymers, or ECPs for electroactive conducting polymers) were discovered in the seventies by McDiarmid, Heeger, and Shirakawa [1] who showed that unsaturated conjugated polymers (polyacetylene, polyphenylene) became conductive when doped, corresponding to the chemical oxidation of the ethylene or polyphenyl carbon chain. 

Polysubstituted thiophenes with other groups different to w-alkyl chain are also known. For example, alkylsulfonate, alkoxy, amide, poly(ether), and acylgroup were introduced in 3-position in thiophene and their electroobtained polymers were studied. A water soluble poly(alkane)sulfonatederivative of thiophene has also been reported [55] which would be an intrinsically conducting polymer (self-doped). Composites of poly(thiophene)s with poly(methylmethacrylate) and poly(vinylchloride) were prepared as... 

Functional polymers appeared in the second half of the twentieth century. Although polyaniline was first described in the mid-nineteenth century by Henry Letheby and polypyrrole derivatives were reported to be electrically conducting in 1963 by B.A. Bolto et al. (1963), substantial progress was not made with intrinsically conducting polymers until the pioneering work of Hideki Shirakawa, Alan J. Heeger, and Alan MacDiarmid who reported similar high conductivity in oxidized iodine-doped polyacetylene in 1977 (Shirakawa 1977). For this research, they were awarded the 2000 Nobel Prize in Chemistry for the discovery and development of conductive polymers. ... 

---