Electrically conducting polymers, potential

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>... 

Open-circuit potential -of conducting polymers [ELECTRICALLY CONDUCTIVE POLYMERS] (Vol 9)... 

In addition to the conventional lithographic techniques, surface patterning was performed by means of local polymerisation of the monomers under the SPM tip. These studies have been mainly focused towards electrically conductive polymers such as polypyrole, polythyophene and polyaniline. The easiest way to implement polymerisation is to set either the tip or sample potential sufficiently positive to cause the electrochemical oxidation of the monomer [438, 451 -455]. This technique enabled controlled removal and deposition of polymer dots as small as 1 nm to in a well defined pattern [453]. After deposition, the dots could be read using a conventional imaging mode (Fig. 49). 

Conjugated Polythiophenes. Because of their potential electrical conductivity, conjugated polythiophenes, along with other conjugated polymeric systems, have been extensively studied since the pioneering works in the early 1980s (65,66) (see Electrically conductive polymers). 

In the past decade, the potential of intrinsically electrically conductive polymers has transformed from a laboratory curiosity into commercial uses. A number of conducting polymers have been studied all of which exhibit a conjugated stmc-ture for a path of electron transfer -specifically when doped. Representative electrically conductive polymers include those shown in Figure... 

Electrically conductive polymers are perspective materials in modern technologies because of their potential applications as chemical sensors, catalysts, microelectronic devices, etc. [1]. The interest to new hybrid nanostructured materials based on polymer matrix with poly-7t-conjugated bonds and noble metals nanoparticles constantly increases. This is reasoned by a wide spectrum of new optical and electrophysical properties [2]. 

Spectroelectrochemistry is one of the many facets of photoelectroanalytical chemistry. It can be used for numerous purposes in solving the mechanisms of electrochemical processes but especially with electrically conducting polymers it shows its main advantages. The original drive to study conductive polymers arose from the applications anticipated in the energy storage, but these polymers are also interesting from the analytical point of view as potential sensor materials. 

An electrically conductive polymer composite of polypyrrole and poly(ethyl methacrylate) has been prepared by an emulsion polymerization procedure [ 142]. In this case, the relation between conductivity and the polypyrrole content of the composite exhibited a percolation behavior, with conductivities as high as 6-7 S/ctn. Such composites might be amenable to melt processing for coating formation. Composite films consisting of polypyrrole or poly(N-ethylaniline) filler dispersed in a polyimide matrix have been described for potential use as corrosion control coatings for the A1 alloy AA 2024-T3 [143]. 

It is possible to reduce interference by ions from the filling solution of a liquid-based ion-selective electrode (Figures 15-13 and 15-15) by replacing the filling solution with an electrically conductive polymer. The filling solution or the conductive polymer translates an electric potential difference at the Ag ion-exchange membrane into an electric potential at the metallic inner electrode. 

Some polymers from styrene derivatives seem to meet specific market demands and to have the potential to become commercially significant materials. For example, monomeric chlorostyrene is useful in glass-reinforced polyester recipes since it polymerizes several times as fast as stsrrene (98). Poly(sodium styrene-sulfonate) [9003-59-2] is a versatile water-solnble polsrmer and is used in water-pollution control and as a general floccnlant (99,100). Poly(vinylbenzyl ammoniiun chloride) [70504-37-9] has been nsefiil as an electrocondnctive resin (101). (see Electrically-Conducting Polymers). 

The synthesis of 3-(perfluoro)-thiophenes and 3-(polyfluoro)-thiophenes as precursors to electrically conductive polymers has been reported (47-53). The incorporation of a significant percentage of fluorine into the polymer is anticipated to allow greater control over its oxidation potential and provide better long-term chemical and thermal stability in the electrochemical environment over that of the nonfluorinated polythiophene analogs. 

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