Grafted Surface Sheared by Short Polymers and the Total Entanglement Threshold

C. Gay

The shear flow of a polymer melt (P monomers per chain) above a solid surface on which longer, chemically identical chains have been grafted (N monomers, N>P), shows that friction at the surface is enhanced and that slippage is much reduced (with respect to the bare surface behavior), provided that the melt is entangled (P>Ne). One important issue in this problem is the drag number X of the tethered chains, i.e. the number of melt chains that they trap. Recently, two different regimes were described [1] for the opposite case NP is discussed: in this case, it is always linear in N, but long chains do display a coil-stretch transition. The value of the minimum molecular weight M* for this effect to take place is also discussed; star polymers should display the high molecular weight behavior even if they are smaller in size: this should allow for a test of the model.

Domaines: Articles anciens

C. Gay. Grafted Surface Sheared by Short Polymers and the Total Entanglement Threshold. Journal de Physique II, 1996, 6 (3), pp.335-353. ⟨10.1051/jp2:1996186⟩. ⟨jpa-00248301⟩