Rheological properties of polymer melt between rapidly oscillating plates: An application of multiscale modeling

Abstract

The behavior of supercooled polymer melt composed of short chains with 10 beads between rapidly oscillating plates is simulated by using a hybrid simulation of molecular dynamics and computational fluid dynamics. The flow profiles of polymer melt near an oscillating plate are quite different from those of Newtonian fluid. The viscous boundary layer of the melt is much thinner than that of the Newtonian fluid due to the shear thinning of the melt. Three different rheological regimes, i.e., the viscous fluid, viscoelastic liquid, and viscoelastic solid regimes, form over the oscillating plate according to the local Deborah numbers. The melt behaves as a viscous fluid when ωτR lsim 1, and the crossover between the liquid-like and solid-like regime takes place around ωτα sime 1 (where ω is the angular frequency of the plate, and τR and τα are the Rouse and α relaxation times, respectively).