Surface Forces related to the Accumulation and Dispersion of Dust due to the Locomotion of a Cantilever

Abstract

Since surface forces prevent micro-machines from moving in the air, there are a lot of difficult problems to be solved concerning the reliability of micro-machines. Surface forces depend strongly on dust and contaminants. Therefore, we should be considering the attachment and detachment of micro-applications between interactive contact surfaces related to the locomotion of micro-machines. We observed that dusts have effects upon contact surface forces via the locomotion of cantilever in the air. First, we made a stainless steel cantilever with a glass sphere (dry borosilicate glass sphere, curvature radius: R=10µm) glued on top. In addition, we created an asperity array at the micro-sphere's surfaces on the stainless steel cantilever using an FIB (Focused Ion Beam). The experiment was performed using an AFM (Atomic Force Microscope). From the results, we found out that contact surface forces are influenced remarkably by dust debris in the air. The spheres with asperity arrays tend to hinder the accumulation of dust than the spheres without asperity arrays in abrading work using the same normal spring constant (=k n ) of the cantilever. Moreover, among the cases with non-asperity arrays, the accumulation of dust on the sphere's surface is lower in the thin cantilever than the wide cantilever. To prevent contact surface forces from increasing by the accumulation of contaminants, micro-machines must have locomotion and asperity arrays on any surface that comes in contact with severe natural conditions.