AN IN-SITU INFRARED SPECTROSCOPIC STUDY OF IMIDAZOLE FILMS ON COPPER ELECTRODES

Organic films electrodeposited on a copper electrode from basic soluti ons containing imidazole were investigated by two different in situ in frared spectroscopic techniques: real-time polarization modulation and static linear polarization reflection absorption spectroscopy. The sp ectra indicate that as the electrode potential is made more positive, the amount of imidazole bound to the electrode surface increases. The coating on the electrode is found to consist mainly of copper(I) imida zolate with either a random or perpendicular orientation to the polycr ystalline surface. No change in orientation of the imidazole ring is s een with the variation in potential. The infrared data from both refle ction techniques indicates that before the Cu(0)/Cu(I) onset the film is formed at the solution metal oxide/hydroxide interface and at poten tials above this, greater than or equal to 2 -0.54 V, a more compact f ilm forms closer to the metal surface. (C) 1998 Elsevier Science S.A. All rights reserved.