The Electrodeposition of Polypyrrole on a Glutathione Self-Assembled Monolayer Modified Gold Electrode and Its Electrochemical Behavior

Abstract

Cyclic voltammetry and chronoamperometry have been used to investigate the electrochemical deposition of pyrrole at glutathione (GSH) self-assembled monolayer modified gold electrodes (GSH SAM/Au). It is shown that GSH monolayer exhibits great influence on the nucleation and growth of polypyrrole (PPy) at the electrode surface. GSH SAM makes the initial polymeric potential and peak potential shift positively and polymeric amount decrease. It can depress the diffusion of ions into PPy film and lower the background signal. Various conditions such as potential, solution pH, supporting electrolyte and surfactant have been tested. It was found that the polymerization could be facilitated at sufficiently positive potential and high pyrrole concentration. The nucleation and growth of polypyrrole at GSH SAM/Au is seriously affected by the solution pH and the polymerization becomes easy at lower solution pH, which is different from that at the bare gold electrode. The primary properties of the resulting film are discussed as well in this article.