Growth Processes and Morphological Evolution of Polyaniline Film During Potentiostatic Growth

We have investigated the potentiostatic growth processes and morphological evolution of polyaniline film on an indium tin oxide (ITO) electrode. The current-time transient shows the existence of three stages in two growth regimes. As the initial formation of polyaniline is extremely fast, the current increases rapidly with time. Subsequently, the current increase is slowed down due to the decomposition reaction competes with polymerization. Polyaniline film grown rapidly on a bare ITO electrode shows a compact two-dimensional layer with a granular structure. The granules start to grow upward on the first layer, with one-dimensional growth resulting in a loosely bound and open fibrous structure. Further polymer film growth results in surface aggregates due to the increased degradation rate. Visualization of the surface morphology and the roughness of the grown film are consistent with the proposed growth processes.