Shear-dependent boundary slip in an aqueous Newtonian liquid - art. no. 054504

We report direct measurements of hydrodynamic drainage forces, which show c lear evidence of boundary slip in a Newtonian liquid. The degree of boundar y slip is found to be a function of the liquid viscosity and the shear rate , as characterized by the slip length, and is up to similar to 20 nm. This has implications for confined biological systems, the permeability of micro porous media, and for the lubrication of nano-machines, and will be importa nt in the microcontrol of liquid flow. We also show that current theories o f slip do not adequately describe the experimental data.