Preparation and investigation of polymer-modified electrodes by square wave voltammetry

Abstract

The first use of square wave voltammetry (SWV) for the preparation and study of polymer-modified electrodes is presented. Modified electrodes have been characterized by many spectral and electrochemical techniques. Of the electrochemical techniqeus, cyclic voltammetry, chronoamperometry, and chronocoulometry have been used most widely. Pulse techniques have seen less use. Differential pulse voltammetry at modified electrodes was found to be well-suited for detecting small coverages and for precise measurements of peak potentials. SWV and cyclic staircase voltammetry are compared as techniques for studying polymer-modified electrodes. (Here cyclic staircase voltammetry is a surrogate for linear scan voltammetry and will be referred to as CV). Films of poly-(Ru(bpy)/sub 2/ (vpy)/sub 2//sup 2 +/ (bpy, 2,2'-bipyridine; vpy, 4-vinylpyridine) were prepared by reductive electropolymerization of the monomer on platinum electrodes by CV or SWV, and their electrochemical behavior was studied by the same two techniques. The Ru(II)/Ru(III) oxidation occurs at 0.92 V vs. Ag/Ag/sup +/ in acetonitrile. The coverages of the modified electrodes ranged from 4.9 x 10/sup -10/ to 1.1 x 10/sup -8/ mol/cm/sup 2/. There were no observable differences between the electrochemical behavior of the films prepared by SWV and by CV. 14 references, 2 figures.