Experimental research on boundary slip of confined liquids at micro/nano scale and effect of shear rate

Abstract

In order to research the flow property of liquids between solid and liquid at micro/nano scale, a commercial atomic force microscope was modified by attaching a glass ball to the end of cantilever at micro/nano scale, which was used to investigate influence of approach velocity on boundary slip. Solid surface specimen was Si(100) verse deionized water. Results indicate that, when the distance between the glass ball and solid surface is below critical value, boundary slip will not affect the hydrodynamic force. The critical distance will decrease with the reducing of the velocity and it means boundary slip is dependent with velocity. The relationship between shear rate and boundary slip was discussed. It shows that boundary slip will occur only when the shear rate reaches some value.