Miniaturization Science for Space: Lubrication of Micro-Electro-Mechanical Systems (MEMS) for Space Environments

In this study, the vapor phase lubrication of interacting gold surfaces has been investigated on the atomic and molecular level using the quartz crystal microbalance QCM, atomic force microscopy AFM and scanning tunneling microscopy STM. These techniques have provided a fundamental understanding of the molecular nature of adsorption, adhesion, and current flow occurring at gold interfaces through the formation of self-assembled monolayers SAMs of conjugated aromatic thiol molecules. The issues of static adhesion and contact performance have been addressed simultaneously in relation to the nature and composition of the interface. Maps of both current and adhesion demonstrated the potential of using conjugated species with fluorine substituents on the basis of their tribological and electrical behavior as candidates for lubricating AuAu interfaces in MEMS devices. Although they do not form a closely-packed geometry compared to n-alkanethiol SAMs, they however provide hydrophobic, Teflon-like surfaces which accounts for the observed low adhesion.