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
pierre-gilles.degennes@espci.fr
Received 19 April 1999
Abstract
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.
PACS
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
