ABSTRACT

This chapter presents an overview of lubrication studies of polar and nonpolar lubricants and Langmuir-Blodgett and chemically grafted films, using atomic force/friction force microscopy. Boundary lubrication properties of lubricants are also dependent upon the molecular conformation and lubricant spreading. The attractive adhesive forces at different parts of the surface can be estimated by bringing the sample into contact with the tip and then measuring the maximum force needed to pull the tip and sample apart, Mate and Bhushan and Ruan. Attempts to measure mechanical properties of self-assembled monolayer films on Au(111) films have been made by Salmeron et al. Mate concluded that the liquid films have negligible shear stress to applied shear strains until the molecules are completely compressed or squeezed out from between the sliding surfaces, showing that hydrodynamic lubrication can occur for surfaces separated by only a few cross-sectional diameters of the polymer backbone.