Self-Doped Ionically Conducting Polymers

These reaction formulae indicate that the electron transfer taking place at the metal I polymer interface is accompanied by ionic charge transfer at the polymer Isolation interface, in order to maintain the electroneutrality within the polymer phase. Counterions usually enter the polymer phase, as shown above. However, less frequently the electroneutrality is established by the movement of co-ions present in the polymer phase, e.g., in so-called self-doped polymers. Oxidation reactions are often accompanied by deprotonation reactions, and H+ ions leave the film, removing the excess positive charge from the surface layer. It should also be mentioned that simultaneous electron and ion transfer is also typical of electrochemical insertion reactions however, this case is somewhat different since the ions do not have lattice places in the conducting polymers, and both cations and anions may be present in the polymer phase without any electrode reaction occurring. The es-... 

Hayamizu K, AUiara Y, Price W (2000) Correlating the NMR self-diffusion and relaxatirai measurements with ionic conductivity in polymer electrolytes composed of cross-linked poly (ethylene oxide-propylene oxide) doped with LiN(S02CF3)(2). J Chem Phys 113(11) 4785 793... 

Mainly sulphonate species have been chosen as internal dopant ions, because of their low reactivity in electrochemical redox processes. In this way, ionic transport in the conductive polypyrrole can be modulated by a high density of anionic sites, thus requiring the cation to be the mobile species. On the other hand, self-doped polymers can be electrochemically prepared without adding a salt to allow conduction [149]. Some of those self-doped materials are soluble in common solvents. 

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