New concepts for the slippage of an entangled polymer melt at a grafted solid interface

Molecular models of interfacial friction between an entangled melt and a compatible polymer brush (irreversibly grafted chains) are discussed. Progress since the 1992 model by Brochard and de Gennes is described, including the impact of the experimental evidence obtained by Durliat (thesis, 1997). A new, more realistic description of interfacial friction is adapted from the bulk tube renewal mechanism. It justifies some earlier results more precisely. It additionally predicts a progressive thinning of the grafted layer when the melt velocity exceeds some threshold value. An outline of the expected chain behaviour at very high grafting densities is given. It includes topological effects similar to combing.