Conductive polymers classes

When doped, low band-gap polymers have optical transitions in the infrared region of the spectmm, and therefore transmit more visible light in the conducting form than in the insulating form. This feature enables this class of conducting polymers to be investigated for a number of optical appHcations where both electrical conductivity and optical transparency are desired. 

Chapters 10 to 29 consisted of reviews of plastics materials available according to a chemical classification, whilst Chapter 30 rather more loosely looked at plastics derived from natural sources. It will have been obvious to the reader that for a given application plastics materials from quite different chemical classes may be in competition and attempts have been made to show this in the text. There have, however, been developments in three, quite unrelated, areas where the author has considered it more useful to review the different polymers together, namely thermoplastic elastomers, biodegradable plastics and electrically conductive polymers. 

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 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... 

It was also observed that, with the exception of polyacetylene, all important conducting polymers can be electrochemically produced by anodic oxidation moreover, in contrast to chemical methoconducting films are formed directly on the electrode. This stimulated research teams in the field of electrochemistry to study the electrosynthesis of these materials. Most recently, new fields of application, ranging from anti-corrosives through modified electrodes to microelectronic devices, have aroused electrochemists interest in this class of compounds... 

A special class of conductors are ionically and electronically conducting polymers (Sections 2.6.4 and 5.5.5). 

This volume combines chapters oriented towards new materials with chapters on experimental progress in the study of electrochemical processes. G. E Evans reviews the electrochemical properties of conducting polymers, materials which are most interesting from a theoretical point of view and promise to open up new fields of application. His approach gives a survey of the main classes of such polymers, describing their synthesis, structure, electronic and electrochemical properties and, briefly, their use as electrodes. 

The discovery of the metallic properties of polymeric (SN)X by Walatka etal. in 1973 brought to notice a new class of materials electronically conducting polymers. The importance of this discovery was enhanced greatly by the... 

All inorganic electrochromes exist in the solid state in both the colourless and coloured states, e.g. Prussian Blue and tungsten trioxide. Conducting polymers such as polyanilines, polypyrroles and polythiophenes also fall into this class of electrochromes (see 1.5.3.5). 

Still higher total conductivities are achievable in a special class of hydrogen-ion (proton)-conducting polymers. These polymers are particularly useful for fuel-cell and chlor-alkaU processing applications in which the efficient transfer of protons is critical. These polymers are of produced in membrane form and are therefore referred to as proton-exchange membranes (PEM). 

The third class of polymers used to prepare chemically modified electrodes is the electronically conductive polymers [25]. The polymer chains in this family of materials are themselves electroactive. For example, the polymer redox reaction for polypyrrole (Table 13.2) can be written as follows ... 

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