Electrochemical characterization of Redox polymer Langmuir-Blodgett films containing ferrocene derivatives

Redox properties of ferrocene derivatives incorporated into polymer Langmuir-Blodgett (LB) films have been investigated using cyclic voltammetry. The copolymers of N-dodecylacrylamide (DDA) with ferrocenylmethyl acrylate (FcA) and with vinylferrocene (vFc) were prepared as amphiphilic redox polymers. The spreading behavior of these copolymer monolayers on a water surface was investigated by measurement of the surface pressure-area isotherms. The isotherms show that the DDA/vFc copolymer monolayer is unstable, whereas the DDA/FcA copolymer forms a stable condensed monolayer on pure water when the mole fraction of FcA is less than ca. 54 mol %. Cyclic voltammograms for the DDA/FcA copolymer LB monolayer transferred on an ITO electrode exhibit a well-defined surface wave. The interfacial electron transfer process between the redox site incorporated to the polymer LB monolayer and the electrode surface is independent of the surface concentration of the redox site in the monolayer. On the other hand, the interlayer electron transfer process across layers in LB films depends on the surface concentration of the redox site.