ELECTRON-TRANSFER IN SURFACTANT FILMS ON ELECTRODES - COPPER PHTHALOCYANINETETRASULFONATE DIDODECYLDIMETHYLAMMONIUM BROMIDE

Ordered surfactant films on electrodes are promising for various appli cations, including catalysis, sensors and fundamental studies. The fir st part of this paper provides a short review of recent results on ele ctron transfer in surfactant and surfactantlike films on electrodes. T he second part of the paper describes an electrochemical study of cast films of copper phthalocyaninetetrasulfonate (CuPCTS) and the water-i nsoluble surfactant didodecyldimethylammonium bromide (DDAB). Films we re prepared by first casting the DDAB films onto electrodes, then intr oducing the CuPCTS by ion exchange from solution, or by casting the fi lms as the CuPCTS(didodecyldimethylammonium), salt. Electrochemical be havior depends upon the method of preparation, which influences the st ructure of the him. The salt films were characterized by overlapped vo ltammetric peaks, while the ion exchanged films showed a well-resolved first reduction process. Analysis of voltammetric data at pH 12 showe d that charge transport diffusion and electron transfer kinetics were significantly faster in the ion exchanged films than in the salt films . The fluid lamellar liquid crystal structure of the ion exchanged fil ms facilitates charge transport compared to the salt films which are n ot liquid crystalline.