Structural modifications during conducting polymer formation - an ellipsometric study

Polyaniline films potentiodynamically synthesised on gold substrates are an alysed ex situ by conventional and imaging ellipsometry (at constant wavele ngth). Polymers grown up to 50 cycles appear to be homogeneous, whereas dif ferent structures are displayed by thicker layers. The memory effect, induc ed by the polymer electrochemical characterisation, in subsequent polymer g rowth, is demonstrated. In the case of thin films, a reliable methodology h as been successfully employed to obtain, from the ellipsometric parameters Delta and psi, the refractive index, the extinction coefficient and the thi ckness of polymer layers. This approach also allowed us to quantitatively e valuate the magnitude of polymer swelling upon oxidation (11 - 22%). Furthe rmore, the surface morphology is well evidenced by the results obtained by imaging ellipsometry. (C) 2001 Elsevier Science Ltd. All rights reserved.