Conducting polymers summary

All this, in summary, would amount to additional sections on conductive polymers and to a future chapter on semiconductive polymers, currently representing an encouraging outlook for a journey begun in serendipity. 

The electron-transfer rate between large redox protein and electrode surface is usually prohibitively slow, which is the major barricade of the electrochemical system. The way to achieve efficient electrical communication between redox protein and electrode has been among the most challenging objects in the field of bioelectrochemistry. In summary, two ways have been proposed. One is based on the so-called electrochemical mediators, both natural enzyme substrates and products, and artificial redox mediators, mostly dye molecules and conducted polymers. The other approach is based on the direct electron transfer of protein. With its inherited simplicity in either theoretical calculations or practical applications, the latter has received far greater interest despite its limited applications at the present stage. 

In Chapter 1 we explain the motivation and basic concepts of electrodeposition from ionic liquids. In Chapter 2 an introduction to the principles of ionic liquids synthesis is provided as background for those who may be using these materials for the first time. While most of the ionic liquids discussed in this book are available from commercial sources it is important that the reader is aware of the synthetic methods so that impurity issues are clearly understood. Nonetheless, since a comprehensive summary is beyond the scope of this book the reader is referred for more details to the second edition of Ionic Liquids in Synthesis, edited by Peter Wasserscheid and Tom Welton. Chapter 3 summarizes the physical properties of ionic liquids, and in Chapter 4 selected electrodeposition results are presented. Chapter 4 also highlights some of the troublesome aspects of ionic liquid use. One might expect that with a decomposition potential down to -3 V vs. NHE all available elements could be deposited unfortunately, the situation is not as simple as that and the deposition of tantalum is discussed as an example of the issues. In Chapters 5 to 7 the electrodeposition of alloys is reviewed, together with the deposition of semiconductors and conducting polymers. The deposition of conducting polymers... 

The discovery that doped forms of polypyrroles conduct electrical current has spurred a great deal of synthetic activity related to polypyrroles [216-218], Reviews are available on various aspects of the synthesis and properties of polypyrroles [219,220]. In addition, summaries of important aspects of polypyrroles are included in several reviews on electrically conducting polymers [221-226]. Polypyrrole has been synthesized by chemical polymerization in solution [227-231], chemical vapor deposition (CVD) [232,233], and electrochemical polymerization [234-240]. The polymer structure consists primarily of units derived from the coupling of the pyrrole monomer at the 2,5-positions [Eq. (84)]. However, up to a third of the pyrrole rings in electrochemically prepared polypyrrole are not coupled in this manner [241]. 

Summaries on the synthesis, properties, and uses of polythiophenes are included in two general reviews on poly thiophenes [259,260]. A synopsis of important aspects of polythiophenes are also included in several reviews on various aspects of conducting polymers [221-226], Cation radicals are the propagating species in both electrochemical and chemical oxidative polymerizations of thiophene and its derivatives. The polymer obtained by this method is linked primarily by a,a-linkages. However, other types of linkages (a,f3 and /3,/3) are present in varying amounts (Fig. 59). Substituted thiophene derivatives can couple in a head-to-tail or head-to-head manner. 

Table 1. Summary of photovoltaic performance of some conducting polymers...

Table 8.4. A general summary of the effects of structural parameters on e and s" values of conducting polymers...

Inorganic-Based Nanocomposites of Conductive Polymers 263 Table 6.1 Summary of data on the FeOCI system... 

Technological uses of conducting polymers may be classified as follows (1) Use based on bulk conductivity of the pure conducting polymer or a blend of the conducting polymer with a conventional polymer (2) Use based on the electrochemical redox properties of the polymer (3) Use based on the formation of an excited state of the polymer (4) Use based on the morphology/microstructure of the polymer. Each of these categories will be summarized below. This summary is based in part on a ery recent concise evaluation of industrial applications of conducting polymers,. ... 

Undoubtedly, many important potential applications of conducting polymers have been omitted in this brief summary. The next decade will certainly bring forth new basic science and applications in the field that are logical extensions of what is already known, as well as completely new unexpected fundamental science and technology. 

In summary, the conductivity and its temperature dependence in doped (CH), PPV, PPy, PANI and PEDOT samples suggests that by reducing the role of disorder-induced localisation in charge transport, it is possible to observe the intrinsic metallic positive TCR in doped conducting polymers. 

This chapter provides a broad summary of recent research activity in the area of CPEs. It is evident that there is great enthusiasm in the conducting polymers community for CPEs. These materials provide a unique opportunity to explore the interactions between electro- and photoactive conjugated polymers with water-borne species such as metal ions and biological macromolecules, including proteins and DNA. Moreover, the ability to use the materials in LbL self-assembly affords researchers a tool for fabrication of heterostructured films of opto- and electronically active materials. This ability has not been easily possible with conventional conjugated polymers that are processed fi om organic solvents. 

CNT are an attractive reinforcing and conducting filler for polymers due to their exceptional mechanical properties, high aspect ratio and excellent electrical conductivity. In summary ... 

As stated earlier, an extensive laboratory review of many available commercial water-soluble polymers and selected experimental water-soluble polymers was conducted. A summary of the results is given in Table I. As shown, only polyvinylpyrrolidone survived the 121 (250 ) test in synthetic seawater more than a few days. Polyvinylpyrrolidone is not however an efficent viscosifier. Combined with its high adsorption characteristics in reservoir rock (polyvinylpyrrolidone has been used in selected cases as a sacrifical agent) and high price, polyvinylpyrrolidone is regarded as unsuitable for use in EOR. 

The most widely investigated systems in terms of sensor desi are the detection of glucose, molecular recognition based on polynucleotides, and antigen/antibody interactions. Table I provides a summary of the type of immobilization, the conducting polymer used, and the parameter measured for a number of the analytical tools that have been developed over the last few years. 

In summary, the following obstacles must be overcome before conducting polymer can be used as Pt supports for commercial applications. First, the electronic conductivity of the composite is often seriously reduced during the Pt deposition process. Second, the resulting Pt/composite gradually loses its electronic conductivity during storage. Third, the irreversible... 

In summary, conducting polymers have a great potential for use in a number of electrochemical applications how this potential will be realized in the future depends on the development of the technology required to make this feasible. 

Table 1. Summary of Photovoltaic Performance of Some Conducting Polymers...

These methods are described in detail in various comprehensive reviews (Malkin and Siling 1991 Skolheim 1986 Kumar and Sharma 1998 Gurunathan et al. 1999 Malinauskas 2001 Reisinger and Hilhnyer 2002). A summary of the reported literature highlighting the polymerization techniques of some widely used conductive polymers is presented in Table 28.10. 

It is to be hoped that this brief summary of the active and constantly changing field of research generally labelled conducting polymers will be of use in introducing readers of this specialist text to a possibly relevant topic, and that it will allow access to the literature and an easier understanding for those who delve further. 

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