Self-Assembled Monolayers: Models for Organic Surface Chemistry

The chemistry of organic interfaces is important to a very wide range of areas of science and technology; examples include the fabrication of microelectronic devices, the formation of structures by adhesion, cell-surface chemistry, the use of organic thin films as lubricants and corrosion protective agents, and a range of phenomena involving wetting and spreading of liquids on organic surfaces. This chapter provides an introductory survey of Self-assembled monolayers (SAMs), concentrating on the best studied of these systems—monolayers of long-chain alkanethiolates on gold. SAMs of alkanethiolates are typically formed by adsorption of an alkanethiol or dialkyl disulfide onto gold from solution; both types of organosulfur compounds form similar SAMs. Scanning tunneling microscopy has recently been able to generate high-resolution images of SAMs by working with very low tunneling currents. Single-component and mixed SAMs of alkanethiolates on gold provide excellent control over the structure of the monolayer perpendicular to the plane of the SAM.