Stochastic chain simulation of wall slip in entangled polymer melts

The stochastic chain model described by Xu et al. [J. Rheology 50, 477-494 (2006)] provides fundamental insight into the mechanism of apparent wall slip in entangled polymer melts. Apparent slip is shown to be a consequence of a rapid decrease in the entanglement density for chains in the region of the wall. There is good agreement between model predictions and polydimethylsiloxane experiments of Durliat et al. [Europhys. Lett. 38, 383-388 (1997)] in which a surface layer containing a known density of tethered chains contacts a bulk melt. The model cannot provide quantitative information about apparent slip when chains are simply adsorbed at the wall, since the surface density and effective chain length are required inputs to the calculation, but it does agree in broad terms with experiments of Mhetar and Archer [Macromolecules 31, 8607-8616 (1998)] on 1,4-polybutadiene. (c) 2007 The Society of Rheology.