Real-time probing electrodeposition growth of polyaniline thin film via in-situ spectroscopic ellipsometry

Abstract

Conductive polyaniline (PANI) acts as one of the most promising electrode materials with cost-effective, facilely synthesized and chemically stable merits. Although electrodeposition is a desirable approach to preparing PANI with high purity and controllable thickness, the growth kinetics of PANI remains ambiguous for the difficulty in detecting the dynamic evolution in the electrode/electrolyte interface with traditional methods. Herein, we employed in-situ spectroscopic ellipsometry to monitor the growth of PANI film under different electrodeposition conditions. The deposition process of PANI with cyclic voltammetry (CV) shows periodic growth alternating with dissolution, and the net growth rate is ∼ 0.22 nm s−1. When adopting the potentiostatic (PS) and pulse potentiostatic (PP) methods, the PANI films undergo nucleation and linear growth, in which the growth rates reach 0.7 and 1.1 nm s−1, respectively. Moreover, in a short time, PS and PP methods are suitable for the preparation of dense and thick PANI films, respectively. This work makes up for the lack of current understanding of the growth kinetics of PANI under different electrochemical methods, laying a basic reference for the precise control of electrodepositing desirable PANI thin films.