When fluid is confined between two molecularly smooth surfaces to a few molecular diameters, it shows a large enhancement of its viscosity. From experiments it seems clear that the fluid is squeezed out layer by layer. A simple solution of the Stokes equation for quasi-two-dimensional confined flow, with the assumption of layer-by-layer flow is found. The results presented here challenge those of Persson and Tosatti [Phys. Rev. B. 50, 5590 (1994)] and show that both the kinematic viscosity of the confined fluid and the coefficient of surface drag can be obtained from the time dependence of the area squeezed out. Fitting our solution to the available experimental data gives a value of viscosity which is approximately seven orders of magnitude higher than that in the bulk.

• Received 16 April 2006

DOI:https://doi.org/10.1103/PhysRevB.74.167401