Abstract
Nanometer-thick liquid lubricant films are used for the lubrication of micro mechanical systems, such as MEMS devices and hard disk drives. For the lubrication design, it is essential to clarify the mechanical properties of such thin films under the shearing motion. In this study, we succeeded in measuring shear rate dependence of viscous friction at high shear rates of 10^5 to 10^8 s^<-1>, which can be comparable conditions in the actual mechanical systems. To measure viscous friction, we used the highly sensitive shear force measuring method, which we called the fiber wobbling method. We observed that viscosity decreased exponentially along with the increase of shear rates, which is called the shear thinning behavior.
