Nucleation and growth mechanism of electropolymerization of aniline on highly oriented pyrolytic graphite at a low potential

Abstract

Nucleation and growth mechanism of electropolymerization of aniline on highly oriented pyrolytic graphite (HOPG) are investigated by a potentiostatic current-time transient technique (i-t) and atomic force microscopic measurements (AFM). The electrochemical data fitted with a theoretical model suggest that there are three types of nucleation and growth, first at the rising part of the i-t curve corresponding to either 2-D instantaneous or 3-D progressive, second at current maxima associated with 3-D progressive and third, at the descending part of the i-t curve due to combination of 2-D instantaneous and 3-D progressive. The ambiguity in the nucleation and growth mechanism at the rising part of the i-t curve is confirmed as 2-D instantaneous from the results of AFM measurements. Hence, the disadvantage of using a single method to study the nucleation and growth mechanism can be significantly rectified by using some other reliable technique like AFM.