Slip at Liquid/Solid Boundaries: Molecular Scale vs Continuum Predictions
The development of micro/nanofluidic devices for actuation of liquid films, droplets or bubbles requires detailed knowledge of the interfacial stresses and boundary conditions governing transport behavior at small scales. While the celebrated no-slip condition at liquid/solid interfaces has proven remarkably successful in reproducing macroscopic flows, there exist notable examples for which this condition leads to a divergence in the viscous shear stress. This singularity is typically relieved by invoking a slip condition, but current models of slip, which are mostly phenomenological in nature, provide little insight into the dynamics of momentum transfer at liquid/solid boundaries. In this talk, we contrast the results of molecular dynamics simulations with hydrodynamic predictions for liquid films in planar shear at low Reynolds number to establish how the local shear rate, liquid structure factor, wall roughness and variations in substrate surface energy affect the degree of slip. The observed deviations offer insight useful to the development of multiscale models.
Sandra Troian, California Institute of Technology