Conductive polymers examples

The initial discovery of ICPs attracted the scientific community, and this in turn led to the development of several conductive polymers. Examples of the most prominent and widely studied ICPs include polyacetylene, polyaniline (PANI), PPy, polythiophene (PT), and poly(phenylene vinylene) (PPV) (Fig. 6.2). 

This article addresses the synthesis, properties, and appHcations of redox dopable electronically conducting polymers and presents an overview of the field, drawing on specific examples to illustrate general concepts. There have been a number of excellent review articles (1—13). Metal particle-filled polymers, where electrical conductivity is the result of percolation of conducting filler particles in an insulating matrix (14) and ionically conducting polymers, where charge-transport is the result of the motion of ions and is thus a problem of mass transport (15), are not discussed. 

Many of the apphcations of conductive polymers utilize theh unique properties and advantages over other material systems, for example low density and controUable electrical properties. The foUowing examples demonstrate the versatility of conducting polymers in technology. 

An example of an ionically conductive polymer is polyethylene oxide containing LiC104, which is used as a solid phase electrolyte in batteries. 

CNT films are also of interest from morphological aspect because their structure provides nanoscale voids within the networks of CNTs. For example, composites with conducting polymers are very interesting both from scientific and technological interests, since we would expect CNTs to give a well-dispersed film. 

The first use of ionic liquids in free radical addition polymerization was as an extension to the doping of polymers with simple electrolytes for the preparation of ion-conducting polymers. Several groups have prepared polymers suitable for doping with ambient-temperature ionic liquids, with the aim of producing polymer electrolytes of high ionic conductance. Many of the prepared polymers are related to the ionic liquids employed for example, poly(l-butyl-4-vinylpyridinium bromide) and poly(l-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide [38 1]. 

Polyfarylene vinylene)s form an important class of conducting polymers. Two representative examples of this class of materials will be discussed in some detail here. There are poly(l,4-phenylene vinylcne) (PPV) 1, poly(l,4-thienylene viny-lenc) (PTV) 2 and their derivatives. The polymers are conceptually similar PTV may be considered as a heterocyclic analog of PPV, but has a considerably lowci band gap and exhibits higher conductivities in both its doped and undoped stales. The semiconducting properties of PPV have been shown to be useful in the manufacture of electroluminescent devices, whereas the potential utility of PTV has yet to be fully exploited. This account will provide a review of synthetic approaches to arylene vinylene derivatives and will give details an how the structure of the materials relate to their performance in real devices. 

The electrochemistry of conducting polymers has been the subject of several reviews2-8 and has been included in articles on chemically modified electrodes.9-14 The primary purpose of this chapter is to review fundamental aspects of the electrochemistry of conducting polymer films. Applications, the diversity of materials available, and synthetic methods are not covered in any detail. No attempt has been made at a comprehensive coverage of the relevant literature and the materials that have been studied. Specific examples have been selected to illustrate general principles, and so it can often be assumed that other materials will behave similarly. 

The diversity of conducting polymers is best illustrated by Krivoshei and Skorobogatov s book,15 although many more examples have since been reported. The most widely studied classes, from an electrochemical point of view, are the polypyrroles, polythiophenes, and polyanilines21 22 (Structures 2-4), and these are the focus of this chapter. A wide... 

Although the electrochemistry of conducting polymers is now a quite mature subject, there is still considerable debate over most of the basic processes. In part, the issues have been clouded by the diversity of different polymers that have been studied. It is often assumed that conclusions drawn from data on a certain polypyrrole, for example, can be extended... 

Other research has been performed with the objective of determining how changes in the structure of the polymer affect the solid ionic conductivity. Some examples are given below. 

Polymers and copolymers are among the most beneficial materials produced by synthetic chemistry. The invention and commercialization of new polymeric materials with radical new properties provides an opportunity to monopolize the market and justify the expense involved in the research and development. The commercialization of new polymers or copolymers always presents scale-up and design challenges. Scientists have recently developed new polymeric materials whose commercial impact has yet to be realized. Examples are semiconductive and conductive polymers and amphiphilic dendritic block copolymers. Other promising materials, such as polymers for (targeted) drug delivery and... 

Another example of ion conducting polymer/ion/solvent systems are polyelectrolytes based on ion-exchange polymers, also called ionomers. The ionic conductivity of ion-exchange polymers is usually very low in the dry state, but increases abruptly by orders of magnitude upon addition of a... 

Table 5.3 Examples of electronically conducting polymers, y is the level of electrochemical doping and k is the maximum electrical conductivity. Except for poly acetylene and polyparaphenylene, only p-doping is considered... 

The synthesis of poly(isothianapthene) (PITN) is an example of the second generation of conducting polymers, which have been prepared in order to produce a material with specific properties. Given the two inequivalent structures of polythiophene which give... 

Besides the conductive additive, TEG may sometimes be a very effective catalyst support, for example, in the catalytic active composite with conducting polymers for the new air-metal batteries, which we proposed [6],... 

The relatively high electronic conductivity of conducting polymers is connected with the presence in polymers of internal system of poly-7t-conjugated bonds. This is easy to understand on the example of a simplest type of conducting polymer (polyacetylene) in the main and activated states (Figure 6). 

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