Polymer slippage: total entanglement threshold

Test of total entanglement threshold Grafted surface sheared by short polymers and the Total entanglement threshold
C. Gay,
J.Phys. II France 6 335-353 (1996) and erratum 6 1121 (1996).
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Abstract / Résumé

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 for the opposite case N < P : a Stokes regime with X=N^{1/2} (total entanglement) and a Rouse regime with X=N/Ne. Here, the structure of the drag number for N > P 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.

 
publications/1996jphysiislippage.txt · Dernière modification: 2011/12/17 20:22 par cgay
 
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