"A study of some electroactive, thin organic films prepared by plasma and electrochemical techniques"

Abstract

Electron Spectroscopy for Chemical Applications (ESCA) and Cyclic Voltaimnetry (CV) have been used to study the surface and electro chemistries of electroactive, thin organic films. A method is developed for the preparation of such films by the synthesis of a molecule containing both an electroactive centre (ferrocene or iron (II) or ruthenium (II) trisbipyridyl) bonded to an electro-polymerizable unit (pyrrole). The surface chemistries of polypyrrole, polyaniline and electrodes potentiostatted in ferrocene solutions were also investigated and results corpared to previous studies where possible. The poly-Ru(II)- and particularly the poly-Fe(II)- films are stable to electrochemical cycling between the +2 and +3 oxidation states. The poly-Fe(II)-, and probably the poly-Ru(II)-, trisbipyridyl films have charge transfer diffusion coefficients similar to those previously reported for other films containing similar redox centres. Redox conductivity has been demonstrated for an aged sample of the poly-Fe(II)- film. Electroactive films, prepared by two different methods of plasma polymerization of substituted ferrocene moncsners are described. In each case the ferrocene/ferricenium electroactivity is degraded, by repeated potential cycling. The incorporation of ferrocene into a plasma polymer does not necessarily produce an electroactive film. A preliminary investigation of the surface and electrochemistry of electrode deposits, prepared by cathodic reduction of perfluorocyclo-pentene, is described. The deposits appear similar in some respects to cathodically reduced PTFE.