The hydrodynamic drainage force of aqueous medium between smooth hydrophilic surfaces was measured with the colloidal probe technique up to shear rates of typically ${10}^4{\mathrm{s}}^{-1\mathrm{}}$. Measured force curves were compared to simulations. To reach agreement between experimental and simulated force curves, the hydrodynamic force had to be fitted with a model allowing for boundary slippage. Boundary slip was characterized by a slip length of $8–9\mathrm{nm}$. Force measurements with charged surfaces could be simulated taking only hydrodynamic and electrostatic double-layer forces into account.

• Received 11 June 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.076103