Compositional Gradients and Electron Flux in Ion-Blocked Multivalent Redox Polymers and Polymer Bilayers: A Theoretical Consideration

Abstract

Redox polymers that are both reducible and oxidizable can be driven to disproportionate when sufficiently large potential biases are applied across the polymer. Moreover, if the polymer is ionic in its original form, this disproportionation can be driven to occur without changes in the net ionic content of the polymer (the so-called ion-blocked case). In the first part of this paper we provide a theoretical description of the steady-state redox gradients that are established in ion-blocked multivalent redox polymers under voltage bias. In the second part of the paper a similar treatment is developed for ion-blocked redox polymer bilayers. The bilayer systems considered are ones in which the oxidation reaction is assumed to be sequestered entirely in one of the polymer layers and the reduction entirely in the other. The two types of polymer systems are compared. Also, comparisons are made between the predicted behavior under ion-blocked and non-ion-blocked conditions. Finally the potential advantages of bi...