MULTILAYER ASSEMBLIES OF REDOX POLYELECTROLYTES

Polyelectrolyte multilayers containing electrochemically active violog en units have been constructed using the layer-by-layer deposition tec hnique with poly(styrenesulfonate) and poly(butanylviologen) as polyan ion and polycation, respectively. All redox active material is electro chemically addressable in multilayers made from these polymers. Cyclic voltammetry, ellipsometry, and W-vis spectroscopy indicate a systemat ic dependence of the amount of material contained in these ultrathin f ilms on the number of deposition cycles, although initial layers are s ignificantly thinner. When the distance between a redox active layer a nd the electrode was varied by interposing non-electrochemically activ e layer pairs, it was determined that the material within the redox ac tive layer was distributed over a distance of at least 2.5 layer pairs away from the nominal location of the redox active layer. This eviden ce for extensive interpenetration between layers was confirmed using v ariable-angle XPS, which revealed a 1:1 stoichiometry between charges on positive and negative polyelectrolytes in multilayers. No salt ions were detected in multilayers.