Rheological study of polymer flow past rough surfaces with slip boundary conditions

Abstract

The slip phenomena in thin polymer films confined by either flat or periodically corrugated surfaces are investigated by molecular dynamics and continuum simulations. For atomically flat surfaces and weak wall-fluid interactions, the shear rate dependence of the slip length has a distinct local minimum which is followed by a rapid increase at higher shear rates. For corrugated surfaces with wavelength larger than the radius of gyration of polymer chains, the effective slip length decays monotonically with increasing corrugation amplitude. At small amplitudes, this decay is reproduced accurately by the numerical solution of the Stokes equation with constant and rate-dependent local slip length. When the corrugation wavelength is comparable to the radius of gyration, the continuum predictions overestimate the effective slip length obtained from molecular dynamics simulations. The analysis of the conformational properties indicates that polymer chains tend to stretch in the direction of shear flow above the crests of the wavy surface.

22 pages, 11 figures; Web reference added for animations: http://www.egr.msu.edu/~priezjev/roughness/text.htm

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Cited by in corpus (8)

• Modeling the combined effect of surface roughness and shear rate on slip flow of simple fluids
• Molecular diffusion and slip boundary conditions at smooth surfaces with periodic and random nanoscale textures
• Shear rate threshold for the boundary slip in dense polymer films
• The relationship between induced fluid structure and boundary slip in nanoscale polymer films
• Molecular dynamics simulations of oscillatory Couette flows with slip boundary conditions
• Interfacial friction between semiflexible polymers and crystalline surfaces
• Multiscale Approach to Fluid-Solid Interfaces: An overview of methodologies coupling fluid mechanics to molecular dynamics and quantum theory
• The effective slip length and vortex formation in laminar flow over a rough surface