Conducting polymer poly-para-phenylene

The first, rather extensive section focuses on polyacetylene. It presents a number of concepts which will not be reintroduced in later sections. The rationale is that the studies of polyaeetylene have been the most comprehensive of all and have preceded similar studies on other conducting polymers. The other two early conducting polymers, poly(para-phenylene) and polypyrrole, will be considered next. Subsequent sections deal with the new polymers, poly(para-phenylene... 

Polyaniline, one of the most studied conducting polymers (in general as well as for corrosion protection), is usually obtained by protonation of what is called the emeraldine base form, shown in Figure 2. The protonation reaction does not change the number of electrons in the polymer backbone. However, starting at the leucoemeraldine form of polyaniline, one would obtain the emeral e salt (conducting) form of polyaniline by an oxidation reaction. Protonic doping has also been observed in the case of alkoxy substituted poly(para-phenylene vinylene) (PPV) ... 

Another class of chemically exceptionally stable polymers are the poly(para-phenylene)s. In addition, they are stiff, rod-Uke polymers. This feature usually tends to cause insolubihty of polymers, which is an attractive approach rod-like polymers can be expected to be insoluble in water at much higher lEC values than polymers consisting of flexible chains, such as poly(arylene ether)s. Since proton conductivity depends on lEC, such polymers have the potential to form membranes with high conductivity at relatively low degrees of swelling and good dimensional and mechanical stability. 

The poly(para-phenylenes)s can be considered rigid rod polymers, which distinguishes them from aU other types of polymers typically used for proton conducting membranes, possibly with the exception of certain polyimides. A striking consequence of the rigid rod structure is the fact that the poly(para-... 

Currently, there are several classes of EAPs that have been shown to exhibit conductivities of metals and semiconductors in the doped state. They are the polyacetylenes, poly(para-phenylene)s, polyheterocycles, poly(phenylene vinylenels, polyanilines, and conjugated ladder polymers. Conducting polymers are made by both chemical and electrochemical polymerization. In the neutral (uncharged) state, EAPs are insulators or semiconductors. Oxidized (p-doped) EAPs have had electrons removed from the backbone, resulting in delocalized polymer cation formation. Reduced (n-doped) EAPs have had electrons added to the backbone, resulting in polymer anion formation. 

Ninivin C. L., Longeau A. B., Demattai D., Palmas P, Saillard J., Coutanceau C., Lamy C., Leger J. M., Determination of the physicochemical characteristics and electrical performance of postsulfonated and grafted sulfonated derivatives of poly(para-phenylene) as new proton-conducting membranes for direct methanol fuel cell. Journal of Applied Polymer Science, 2006, 101, 944—952. 

The absorption spectrum of poly(2-methoxy-5-(2 -ethyl-hexyloxy)-para-pheny-lene vinylene) (MEH-PPV) is shown in Figure 7-8a. Phenylene-based conducting polymers such as MEH-PPV exhibit multiple absorption features extending well... 

Knowing the band structure provides some interesting predictions about the potential properties of a conjugated organic polymer. As such, it is valuable to be able to predict or rationalize band structures. As always, computer programs are available to calculate band structures at the HMO level and beyond. There is considerable value in being able to predict prototype band structures, however, as this allows you to understand and interpret the results of sophisticated calculations. To develop this skill, we describe here the band structure of an infinite polymer of para-linked benzenes, poly(p-phenylene), PPP, another prototype and an important material in the conducting polymers field. 

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