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

The preparation and characterization of octadecylsilane, C18, monolayers on indium–tin oxide (ITO) have been studied carefully. A reproducible procedure was developed for the formation of C18/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.