Quasi-equilibrium voltammetric curves of polaron-conducting polymer films

This article continues modeling of the polaron conductance of polymer films in the general case of an arbitrary number of polymer repeat units included into the polaron structure. The main feature of the proposed approach is stipulated by the introduced definition of reduced quasi-particles as species that contain only one repeat unit of polymer chains, but not the same their quantity (usually, 3-6 units) included into polaron species according to the previously accepted description of polaron-containing polymer films. For a homogeneous population of polarons, every one of which contains the same number of repeat units, the analytical dependence of CV shape on such number m has been derived with a use of the proposed approach. The case of the simultaneous existence of two polaron kinds including different numbers of repeat units is also considered in scope of the applied method. The performed consideration leads to the following results. The quasi-equilibrium voltammetric curves derived with this approach are in a better agreement with experimental CV of conducting polymers than those calculated according to the approach accepted previously. In particular, the mid-widths of CV peaks calculated even without accounting for the so-called short-range interactions result in proximity to the actual values observed for various conducting polymers. In addition, such peculiarities of the real voltammetric curves, as the existence of several peaks or shoulders in their shape and the appearance of a plateau-like tail at high positive electrode potentials can be obtained with using simple assumptions.