Electrochemically Initiated Polymerization Processes

The electrochemical oxidation of monomers such as pyrrole,2-5 thiophene,6-9 aniline,10-13 etc., or their derivatives, initiates a polymerization process at the electrode/electrolyte interface that promotes the formation of a polymeric film that adheres to the electrode. A similar homogeneous polymerization process can be initiated by chemical oxidation or chemical polymerization.14-21 Some monomers can be polymerized as well by electrochemical or chemical reduction. 

This contribution reviews recent results on [Si(Pc)0]n (Pc = phthalocyaninato) solid state electrochemistry and the structural interconversions that accompany electrochemical doping/undoping processes. In aceto-nitrile/(a-Bu)4N+BF4, it is found that a significant overpotential accompanies initial oxidation of as-polymerized [Si(Pc)0]n. This can be associated with an ortho rhomb ic- te tr agonal structural transformation. 

The electrochemical polymerization process is achieved by polymerization of monomers in an electrolytic cell (Subramanian and Jakubowski, 1978). The electrode is the source of active species that initiates the polymerization. It is necessary to select a solvent electrolyte system which is capable of forming a solution with the monomer and having sufficient current-conducting properties. In the process employed by Bell and coworkers (Bell et al., 1987 Wimolkiatisak and... 

Chromatography of CjqO (1) on neutral alumina leads to an efficient conversion into CgQ in 91% yield [15], The same conversion is observed during electrochemical reduction of CjqO. Cyclovoltammetry of CjqO shows three reduction waves [37, 38], whereas C qO is - as expected - a stronger electron acceptor than C q. The transfer of the first electron is assigned to a cage reduction. C gO is not stable and decomposes to Cgg. The transfer of the second electron is believed to initiate a polymerization process of CggO . 

Silvestri,G., Gambino, S., and Filardi,G. Electrochemical Production of Initiators for Polymerization Processes. Vol. 38, pp. 27-54. 

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