During the last years nanostructured films were used for electrode modifications. The hybrid inorganic-organic multilayers films were obtained based on the interaction of the film components. The layer-by-layer (LBL) method was very often used for fabrication of such nanostructured films. Hybrid nanostructured organic, and inorganic-organic films produced by LBL technique can be used for investigation of new approach in electrochromism, electrocatalysis, bioelectrochemistry and electroanalysis. Much attention has been paid also to the metal hexacyanoferrates used as redox mediators in LBL-type films since they are mixed valency clusters exhibiting relatively fast electrons transfer in reduction and oxidation processes . The layer-by-layer method was used for preparation of multilayer hybrid conducting polymer stabilized copper hexacyanoferrate films in which 4-(pyrrole-1-yl) benzoic acid (PyBA) grafted on the glassy carbon electrode (GC) was exposed to Cu2+ and [Fe(CN)6]3- solutions. It is known  that 4-(pyrrole-1-yl) benzoic acid forms monolayers on GC electrode. The surface pKA of 4-(pyrrole-1-yl) benzoic acid adsorbed layer was estimated from cyclic voltammetric measurements of electron transfer processes of [Fe(CN)6]3-/4- in the solutions of various pH’s. The copper hexacyanoferrate-PyBA multilayer films exhibited well-defined electrochemical behavior and high stability. Electrode reactions of such films were found to be sensitive on the presence of various alkali metal, NH4+ or Tl+, ions. The selectivity coefficients , KK/M, of such composite electrode were estimated. One should also stress that observed voltammetric peaks for the studied system have been well-defined and well-separated from other electrode reactions what makes such electrode useful in potential applications.
1. D.R. Shankaran, S.S. Narayanan, Sensors & Actuators B 86 (2002) 180
2. B. Kowalewska, K. Miecznikowski, O. Makowski, B. Palys, L. Adamczyk, P.J. Kulesza, J. Solid State Electrochem., 11 (2007) 1023