Frictional performance of silica microspheres

We present a fundamental study of the frictional performance of silica microspheres, either 4, 2, or 0.5 μm in diameter, on a silicon substrate. The tribological properties of these rolling systems were measured with a ball-on-flat tribometer at various loads. The frictional performance of the rolling systems is found to be highly dependent on load and sphere diameter. Rolling motion was confirmed by imaging the surface of microsphere systems that have been coated with a thin layer of gold. In addition, the surface energy of the lubrication scheme was altered using coatings containing octadecyltrichlorosilane or (tridecafluoro-1,1,2,2-tetrahydrooctyl)-1-trichlorosilane precursors.