Electrochemistry of polyacetylene

MacDiarmid, A.G., et al. 1984. Aqueous chemistry and electrochemistry of polyacetylene and polyaniUne AppKcation to rechargeable batteries. Polym Prep Am Chem Soc Div Polym Chem 25 248. 

MacDiarmid, A.G., et al. 1981. Electrochemistry of polyacetylene, (GH), Lightweight rechargeable batteries using (GH), as the cathode-active material. Org CoatPlast Chem 44 372. 

In order to understand the way polymer-coated electrodes function, a few results on the modification of carriers by electrochemically active, low molecular weight compounds are included (for more details see The electrochemistry of polyacetylene is also mentioned. Coatings of pyropolymers obtained by high temperature treatment of electrochemically inactive and insulating saturated polymers are omitted from this article, as are graphite and its modification. 

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... 

While 7t-conjugated polymers that can be prepared electrochemically in situ on the electrode surface can be characterized rather easily, those that cannot be prepared are more difficult to study. This is because polymer films must be casted in the form of their solutions on electrode surfaces. For a polymer like polyacetylene (PA), it is difficult to dissolve in most organic solvents because of its extremently low solubility. Thus, early studies were carried out with ohmic contacts of pressed pellets of PA with metal current collectors, although PA films were shown to be prepared in situ directly on the electrode surfaces [312], For this reason, electrochemical studies of PA have not been conducted as extensively as for PAn, PPy, PTh, etc., which we discussed rather extensively in the previous section. We discuss the electrochemistry of PA in this section as a representative example of 7t-conjugated polymers, which are not prepared by electrochemical techniques. 

This chapter features mainly the electrochemistry of films of polypyrrole, polythiophene, and polyaniline on various support electrode surfaces. In a historical sense, polyacetylene predates these conducting polymer candidates. Electrochemically oriented studies on this material have been discussed in previous reviews [326-328],... 

The synthesis of conducting polymers can be divided into two broad areas, these being electrochemical and chemical (i.e., non-electrochemical). Whilst the latter may be considered to be outside the scope of this review, it is worth noting that many materials which are now routinely synthesised electrochemically were originally produced via non-electrochemical routes, and that whilst some may be synthesised by a variety of methods many, most notably polyacetylene, are still only accessible via chemical synthesis. In view of this it is useful to have an appreciation of the synthesis of these materials via routes which do not involve electrochemistry. 

Although it was initially believed that polyacetylene was unstable in contact with water under all conditions, it has been successfully chemically doped in aqueous solutions with no apparent degradation of the material [82] and its electrochemistry has also been investigated [135-137] from which it is clear that no degradation occurs in concentrated aqueous electrolytes. Reaction with water can occur under some circumstances however giving rise to sp3 carbons and carbonyl-type structures [129, 138-141],... 

Small-angle neutron and x-ray scatterings were combined with electrochemical measurements for PA-enriched polyisoprene copolymers in order to understand the differences in oxidation-reduction properties and charge storage in the copolymer as compared with the behavior of separate homopolymers [121]. Microphase separation to micelle-like structures with the polyacetylene component surrounded by a nonoxidizable polyisoprene occurs in a solution, in electrodeposited films, and in solvent-cast films and affects the electrochemistry and the netics of charge storage. Electrodeposition of the copolymers is a possible route of copolymer separation from the mixed homopolymer. 

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