[2Ep01-05] Toward Multiscale Tribology Bridging Nano- and Macro-scale: Science of Friction Division's Session

[2Ep02] Shear thinning of lubricant liquids in nanoscale confinement: comparison with macroscopic elastohydrodynamic contacts

*Shinji Yamada¹ (1. Kao Corporation)

Shear thinning is a non-Newtonian behavior of liquid lubricants whose viscosity decreases with the increase in shear rate. Shear thinning is widely observed for a variety of liquid systems both in nanoscopic and macroscopic experiments; the mechanisms are very complex which attracts considerable attention. In this talk, shear thinning of molecularly-confined lubricant liquids investigated using the surface forces apparatus (SFA) will be described. The results were contrasted with shear thinning studied using different approaches; nanoscopic measurements by means other than the SFA, computer simulation of confined liquids, and simulation of macroscopic elastohydrodynamic lubrication will be examined. Although sliding conditions such as velocity, pressure and temperature are very different, molecular mechanisms involved in the shear thinning could have something in common with each other: glass-like feature of lubricant liquids under extreme conditions.