Preparation and characterization of octadecylsilane monolayers on indium-tin oxide (ITO) surfaces

The preparation and characterization of octadecylsilane, C-18, monolayers on indium-tin oxide (ITO) have been studied carefully. A reproducible procedure was developed for the formation of C-18/ITO employing octadecyltrimethoxysilane (OTMS) as a monomer. The films were studied by means of electrochemistry, wettability, infrared and atomic force microscopy. All these measurements provide evidence for the formation of a disorganized, 'brush-type' monolayer with a maximum surface fractional coverage of 0.90 +/- 0.04. The surface coverage can be controlled through the silanization time. The applications and implications of such disorganized monolayers in electroanalytical chemistry are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.