Effect of Surface Roughness on the Measurement of Boundary Slip Based on Atomic Force Microscope

Boundary slip has been widely studied for its potential applications in micro/nanofluidic systems and the colloid probe atomic force microscope (AFM) has been used to measure the boundary slip. When measuring the slip length by using AFM, the surface roughness on both the colloid probe and the measured surface will affect the measurement result and induce an error. In this work, the effect of the roughness on the measurement of boundary slip by using AFM is analyzed and minimized. It is found that the measurement result can be corrected by using the roughness parameters R _pm to minimize the effect of roughness on the measurement. Previous studies of the boundary slip are corrected, and un-ignorable differences are found between the corrected and uncorrected measurement results of slip length on sample surface with a large roughness, which shows the necessity of the consideration of the surface roughness.