Nanoscale Dimensional Changes and Optical Properties of Polyaniline Measured by In Situ Spectroscopic Ellipsometry

The thickness and optical properties of polyaniline films deposited on gold substrates by electropolymerization were determined using in situ spectroscopic ellipsometry. The polymer films were deposited by potential cycling in 0.1 M aniline/ 1 M H 2 SO 4 . For the simultaneous determination of optical properties and thickness, two approaches were used: (i) The evolution of the ellipsometric parameters 4 and ψ at a constant wavelength was evaluated assuming a homogeneous layer growth resulting in a parabolic growth curve with a film thickness of ca. 65 nm (reduced state) after 40 cycles