Rheological evidence for a dynamical crossover in polymer melts via nonequilibrium molecular dynamics
A certain "critical" molecular weight controls rheological properties of the multibead finitely extensible nonlinear elastic (FENE) chain model polymer melt. The rheological crossover manifests itself in a change of power law behavior for the viscous properties at a critical number of beads per chain N(c) = 100+/-10. This finding confirms a newly proposed relationship between dimensionless critical weight, characteristic length, and flexibility which we obtain as a side result. Results further suggest that the entanglement molecular weight N(e) for the flexible FENE chain model could be comparable in size or even larger than its critical molecular weight N(c).
Kroger
M
Institut fur Theoretische Physik, Technische Universitat Berlin, Hardenbergstrasse 36, D-10623 Berlin, Germany and Polymer Physics, Institute of Polymers, ML H 18, ETH Zurich, CH-8092 Zurich, Switzerland.
Hess
S