Effect of polyelectrolyte interdiffusion on electron transport in redox-active polyelectrolyte multilayers

Abstract

We report that polyelectrolyte interdiffusion has a strong influence on the speed of electron transport in redox-active polyelectrolyte multilayers. For interdiffusive polyelectrolyte multilayers, the measured electron diffusion constants were consistently two orders of magnitude larger than the ones for systems where interdiffusion was not possible. This finding was verified for different polyelectrolyte multilayer systems that either allowed or prevented polyelectrolyte interdiffusion. The electron diffusion constants were deduced from cyclic voltammograms at various scanning speeds using the Randles–Sevcik equation for irreversible redox processes. The increased speed of electron transport in interdiffusive multilayers is explained by short-range movement of the redox-sites, allowing fast electron exchange through physical contact of neighboring redox-sites.