Direct observation of removal of SiO₂ nano-particles from silica surfaces: an evanescent field microscopy study and shear flow acting moment

It has been difficult to detach smaller abrasive nano-particles from polished surfaces. In this article, we observed the behaviors of o50, 70, and 300 nm SiO2 particles on a silica surface in an inevitable liquid nano-scale shear flow field as a rinse cleaning by using an evanescent light. These results implied that larger-sized particles were detached because the quantitative moment in the shear flow acting on the particle is considerably higher than those of the sub-100 nm particles. The acting moment would be able to describe the detachability of the nano-particles on the surface.