Effect of surface roughness on rate-dependent slip in simple fluids

TitleEffect of surface roughness on rate-dependent slip in simple fluids
Publication TypeJournal Article
Year of Publication2007
AuthorsPriezjev, NV
JournalThe Journal of Chemical Physics
Date Published10/2007
Keywordselastic constants, interface roughness, liquid films, molecular dynamics method, slip, surface roughness, thin films

Molecular dynamics simulations are used to investigate the influence of molecular-scale surface roughness on the slip behavior in thin liquid films. The slip length increases almost linearly with the shear rate for atomically smooth rigid walls and incommensurate structures of the liquid/solid interface. The thermal fluctuations of the wall atoms lead to an effective surface roughness, which makes the slip length weakly dependent on the shear rate. With increasing the elastic stiffness of the wall, the surface roughness smoothes out and the strong rate dependence is restored again. Both periodically and randomly corrugated rigid surfaces reduce the slip length and its shear rate dependence.