Following recent experiments on thin films of simple molecular liquids confined between two solid plates, a simple model of the effective viscosity is proposed based on the assumption of wall-induced solid-like order in the liquid film. The ordering produces a dramatic increase of the viscosity as film thickness approaches molecular dimensions. Shear-induced melting of these solid-like boundary layers gives rise to non-Newtonian shear-rate dependence of the viscosity. The results are compared with the observations of Granick and co-workers, and further experiments are proposed.
Bibliographical noteFunding Information:
The authors would like to thank B. O'ShaugnessyJ., Kornfeld, M. Deutsch and S. Granick for helpful discussionsa nd comments. This researcwh ass upportebdy the BasicR esearch Foundatioand ministerebdy the IsraelA cademyo f Sciencesa nd Humanities.