Polymer systems, conducting

These results illustrate that electrochemical techniques can be employed to synthesize a vast range of [Si(Pc)0]n-based molecular metals/conductive polymers with wide tunability in optical, magnetic, and electrical properties. Moreover, the structurally well-defined and well-ordered character of the polymer crystal structure offers the opportunity to explore structure/electro-chemical/collective properties and relationships to a depth not possible for most other conductive polymer systems. On a practical note, the present study helps to define those parameters crucial to the fabrication, from cheap, robust phthalocyanines, of efficient energy storage devices. 

Typically, the most common precursors to new Si-N-P systems are simple silylaminophosphines (eq 1). The difunctional character of these compounds, which is due to the nucleophilic site at phosphorus and a complementary electrophilic site at silicon, makes them very versatile reagents. They have been used in a new synthesis of alkyl and/or phenyl substituted phospha-zenes (R2PN)jj ( ) and have led to the preparation of promising precursors to potentially electrically conducting polymer systems of general formula (RPN)n>... 

Hoshino K, Inui M, Kitamura T, Kokado H. Fixation of dinitrogen to a mesoscale solid salt using a titanium oxide/conducting polymer systems. Angew Chem 2000 112 2558-61. 

As demonstrated in Chapter 7, this field is very vital and innovative. A large variety of systems are currently being studied, and several promising battery systems based on these conducting polymer systems are being developed and commercialized. 

K. Yoshino, K. Tada, A. Fujii, E.M. Conwell, A. Zakhidov, Novel photovoltaic devices based on donor-acceptor molecular and conducting polymer systems, IEEE Trans. Electron Devices 44 (1997) 1315-1324. 

The electrical conductivities of conducting polymer systems range from those of insulators <10-10 S cm-1 to values typical for semiconductors 10-5 S cm-1... 

Fig. VI-3 shows a schematie diagram of the electrical conductivity vs. temperature (In tr vs. In T) in the vicinity of the metal-insulator transition. Each of the curves shown in Fig. VI-3 is drawn for a different degree of disorder for a given conducting polymer system, each curve would represent data obtained from a sample with different resistivity ratio, Precisely at the critical point (where the mobility edge is precisely at the Fermi energy), the conductivity follows the power law of Eqn VI-6. On the metallic side, the resistivity remains finite as the temperature approaches zero as indicated in Eqn VI-5. On the insulating side, the resistivity falls below the power law as a result of the exponential dependence that results from variable range hopping see Eqn VI-8 and VI-9.

The confinement of conducting polymers in low dimensions has been studied by several groups. Many of the conducting polymer systems reported to date comprise either two-dimensional thin films, or polymer fibrils at much larger than molecular dimensions. 

This technique has been used to study the wettability of different conducting polymer systems (see Table 1.8) and how this is influenced by the counterion incorporated during synthesis and/or functionalization of the monomer.156 The monomers studied are shown in Table 1.8. 

The electrochemical properties of conductive polymer systems are important with regard to understanding the electrochemical doping process and in applications of conductive polymers as battery electrodes. We have developed a computational method, based on the Valence Effective Hamiltonian technique, which is remarkably effective in the computation of oxidation and reduction potentials of a variety of conjugated polymers (polyacetylene, polyphenylene, polythiophene, polypyrrole) and their oligomers. 

A number of organic polymers become electrically conducting on addition of electron donors or acceptors.(1-5) Despite the enormous interest in these conducting polymer systems, many theoretical aspects of the problem remain poorly understood, especially with regard to the electronic properties of the "doped" (partially ionized) polymers. Progress is being made, however, in understanding the undoped polymer precursors. In a series of recent papers, we have demonstrated the utility of the... 

Portable electronic noses were used for outdoor air monitoring of sewage odors. One conducting polymer system and one MOS nose were used to compare results... 

Polyanilines, from an industrial point of view, are in many applications the preferred conducting polymer system, as they offer a munber of advantages over other conducting polymers. They are generally... 

A number of other redox-dopable conducting polymer systems are also known such as those made by doping covalently-linked siloxane-phthalocyanine complexes, [Si(Pc)0]x, but the above systems and their derivatives have been the most extensively investigated,. ... 

Chandrasekhar, R, G.C. Birur, P. Stevens, S. Rawal, E.A. Pierson, and K.L. Miller. 2001. Far infrared electrochromism in unique conducting polymer systems. Synth Met 119 293-294. 

Such research for new, highly-conducting polymer systems has been very encouraging and in a few years substantial progress has been achieved. The results are reviewed and evaluated in detail in Chapter 3 of this book. 

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