Abstract
Lubrication by a molecularly thin film has become very important in micro machines, magnetic recording disks and so on. When, the thickness of the lubricant film is thinned to several nanometers, physical properties of the film would become different from that of the bulk. Therefore it is important to know these properties. Quartz crystal microbalance (QCM) is common in thin film growth, where it is used for film thickness measurements. The quartz crystal oscillates in transverse shear mode near its resonant frequency that is affected by the adsorbed mass of non-viscous elastic film or the viscosity and the density of the adsorbed liquid. By using this relation, QCM allows one to evaluate viscoelastic properties of adsorbed layer on a surface.
