Electrooxidation of aromatics to polymer films

Abstract

This report describes the electrochemical preparation and properties of polyaniline films prepared on a bare platinum electrode and on electrodes precoated with a thin film of inert polymer. Films were prepared and studied in several aqueous acid electrolytes including sulfuric, hydrochloric, nitric, trifluoromethylsulfonic, hydrofluoric and trifluoroacetic acid. It is observed that both the concentration and nature of the acid influence the kinetics of the switching reaction. In the more acidic solutions, the reaction has at dependence and depends on the movement of a front across the thickness of the film. In the less acidic solutions, the reaction has a t1/2 dependence and depends on the diffusion of ions in the film. The same response is observed for the oxidation and the reduction reaction. Polyaniline is also electroactive in other various nonaqueous solvents, such as, alcohols, acetic acid and acetonitrile, and voltammograms with well defined waves result when solution contains both organic salt and protic acid. Polyaniline was also prepared on a platinum electrode coated with an inert polymer film such as polymethylmethacrylate (PMMA). The resulting polymer blend is electroactive and the switching reaction is slower than for polyaniline formed on a bare platinum electrode. Finally, a brief description is given of electroactive polyaniline films which can be prepared by polymerization of aniline in a glow discharge.

Electrochemically Active Polymers for Rechargeable Batteries

“…between −0.2 or 0.0 V and +0.8 V vs SCE in 1 M HCl, , 0.1 M H 2 SO 4 , or 1 M H 2 SO 4 ,− ,,, HCl, , H 2 SO 4 , ,,,, CF 3 COOH, , and HBF 4 . ,,, The polymer has been deposited on substrates ranging from the metals Au, ,, Pt, ,,,,, Pt-coated Ti, and stainless steel ,,, to SnO 2 68,72 and carbon. ,,,,,,, …”

Mass and Charge Transport in Electronically Conductive Polymers

“…This may result from trapping as described by Reiss et al (83,84). Most of the quantitative evaluations of the redox rates of the electrochemically synthesized electronically conductive polymers were made using large amplitude electrochemical methods (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42); this is unfortunate because, as discussed in detail in the preceding section, it is not clear that these data have any real significance. However, previous investigations have illuminated a number of interesting features about the redox reactions of electronically conductive polymers; we review some of these features and make recommendations about directions of future research in the following paragraphs.…”

An interpretation of small values of the transfer coefficient at conducting polymers

“…The growth is caused by the successive conversion of the insulating zone to the conducting zone by electrochemical oxidation, starting from the electrodejfilm interface toward the filmjsolution interface [8,17,18]. This concept has been suggested by Lacroix and Diaz [19] before these detailed experimental results. It has been realized theoretically from a view point of mass transport [11,13,20].…”