A MODEL FOR SLIP AT POLYMER SOLID INTERFACES

A steady-state dependence of slip velocity on shear stress at polymer/ solid surfaces is derived from a molecular model that includes effects of drag on polymer chains, disentanglement, and detachment and reatta chment of chains from the solid surface. The dependence includes two t urning points and thus a region where slip velocity is a multivalued f unction of shear stress. This behavior is consistent with experimental observations of abrupt and hysteretic transitions between regimes of small and large slip. Parameters involved in the model are estimated a nd a reasonable comparison with experiment is obtained. (C) 1998 The S ociety of Rheology. [S0148-6055(98)01106-7].