Friction and slip of a simple liquid at a solid surface

We report a novel experimental technique using total internal reflection - fluorescence recovery after photobleaching (TIR-FRAP) to probe the velocity of a liquid near a wall with a resolution of the order of 100 nm. As an ex ample of use, we have investigated the boundary condition of the liquid vel ocity during lubricated friction and studied the influence of a classical a dditive (stearic acid) in a base oil (hexadecane), and demonstrate that sim ple Newtonian fluids can develop slip at the wall.