Eur. Phys. J. E 1, 93-97
Viscosity at small scales in polymer melts
F. Brochard Wyart1 - P.G. de Gennes2
1 PSI, Institut Curie, 11 rue P. et M. Curie, 75231 Paris Cedex 05, France
2 Collège de France, 11 place M. Berthelot, 75231 Paris Cedex 05, France
Received 19 April 1999
Flows around small colloidal particles of diameter b, or in thin films, capillaries, etc., cannot always be described in terms of the macroscopic polymer viscosity. We discuss these features for entangled polymer melts, where two distinct regimes can be found: (a) the thin regime where b is smaller than the coil radius R0, but larger than the diameter of the Edwards tube; (b) the ultrathin regime, where . We consider (i) non adsorbing particles, where slippage may occur between the melt and the solid surface; (ii) ``hairy'' particles, which carry some bound polymer chains. We obtain scaling predictions for mobilities of spheres, of needles, and of clusters of particles. We also discuss translational and rotational diffusion of needles.
05.60.Cd Classical transport - 82.70.Dd Colloids - 83.70.Hq Heterogeneous liquids: suspensions, dispersions, emulsions, pastes, slurries, foams, block copolymers, etc.
Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag