Self-Doped CPs

The sodium salts and the acids of poly-3(2-ethanesul-fonate) thiophene and poly-3-(4-butanesulfonate) thiophene are the first known examples of water soluble CPs many other examples of water-soluble, self-doped CPs are given in recent reviews. Indeed, it is well known that the incorporation of highly soluble sulfonate groups on the CP backbone is a common method of achieving water solubility in a doped CP. The two most popular routes are the use of sulfonated polymeric dopants and the polymerization of sulfonated monomers. 

Solubility and processing of CPs have much in common with the related subjects of CP composites and template-based polymerizations, and some elements in common with self-doped CPs. These subjects are however excluded from this chapter and dealt with in Chapters 5, 9 and 10, to which reference is made. 

Self-doped CPs are discussed in more detail in a separate section in a subsequent chapter. We however give here a brief discussion pertinent to their solubility characteristics. 

A typical example of "self-doped" CPs is shown in Fig. 8-3. [255], produced via simple sulfonation of P(ANi) with fuming H2SO4. The metal (e.g. Na) salt form of this CP is highly soluble in water, and can be used to cast films, which are however insulating. Conductivity and solubility data for cast films of the protonated form however apparently indicate that, while conductive (ca. 0.1 S/cm), these films do not redissolve, just as for the sulfonated P(PV) derivative (8.1) above. The "self-doped" nomenclature arises from the appearance that the sulfonate group, a typical dopant... 

Typical example of "self-doped" CP, after Reference [255]. 

Fig. 8-4 Examples of other self-doped CP" structures, after References...

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