Electrochemical Properties of Polyacrylic Acid Film on Gold, Platinum and Glassy Carbon Electrodes in Aqueous Solutions

Abstract

In this paper, we demonstrate for the first time that modifying glassy carbon (GC), gold (Au) and platinum (Pt) working electrodes with poly acrylic acid (PAA) enhances their rate of electron transfer at the electrode-polymer interface. Cyclic voltammeter of potassium ferricyanide on all the electrodes (Au, Au/PAA, Pt, Pt/PAA, GC and GC/PAA) used in this work gave a one reduction and one oxidation peak supporting the well known single redox step for Fe(III)/[Fe(II). The formal redox potentials (E^o') for this system were found to be 0.142V for Au, 0.058V for Au/PAA, 0.057V for Pt, 0.017V for Pt/PAA, 0.222V for GC and 0.063V for GC/PAA versus Ag/AgCl. While the apparent heterogeneous rate constant (k_s)for the Au/PAA and GC/PAA modified electrodes were 100 times higher compared to plain Au and plain GC electrodes. For Platinum electrodes, k_s values for Pt/PAA were 15 times higher compared to those of plain Pt. The diffusion coefficient (D_o) found were as follows: 0.003x10^-7cm²/s (Au), Au/PAA was 1.790x10^-7cm²/s(Au/PAA), 0.004x10^-7cm²/s(Pt), 0.016x10^-7cm²/s(Pt/PAA), 0.001x10^-7cm²/s(GC) and 0.032x10^-7cm²/s(GC/PAA). Overly, this indicates that the PAA modified electrodes carries enormous potential in electro analysis.