Electrochemical electron‐transfer process of polymers containing N‐methylphenothiazine

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Abstract
For a fundamental study of the electrochemical behavior of electroactive polymers a series of poly(3‐vinyl‐10‐methylphenothiazine) (polyMPT), copolymers of 3‐vinyl‐10‐methylphenothiazine and methyl methacrylate (MMA) (copolyMPT), and 3‐ethyl‐10‐methylphenothiazine (EMPT) (a related monomer model) were prepared. The methylphenothiazine groups in these compounds showed reversible, one‐electron oxidation waves in the triangular‐were voltammograms. From a detailed comparison of the voltammograms between these polymers and EMPT it was revealed that the electroactive groups in poly MPT were not the “noninteracting” centers in the strict sense, whereas those in copolyMPT, in which the centers are spaced with the MMA segments, were typically noninteracting in nature; that is, in polyMPT the oxidation takes place at the potential 40 m V lower than that of EMPT and copolyMPT exhibited a wave identical to that of EMPT in shape and potential. The exhaustive electron transfer occurred from polyMPT to the electrode. On the other hand, a significant number of centers remained unoxidized in copolyMPT. The self‐exchange electron transfer within the polymer coil facilitates the exhaustive oxidation. For this event the proximity of the centers was an essential factor.