Journal Article

PreJuSER-17823

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Constitutive equations for the flow behavior of entangled polymeric systems: Application to star polymers

Briels, W. J. ; Vlassopoulos, D. ; Kang, K.FZJ* ; Dhont, J. K. G.FZJ*

2011
American Institute of Physics Melville, NY

This record in other databases:    

Please use a persistent id in citations: http://hdl.handle.net/2128/7351  doi:10.1063/1.3560616

Abstract: A semimicroscopic derivation is presented of equations of motion for the density and the flow velocity of concentrated systems of entangled polymers. The essential ingredient is the transient force that results from perturbations of overlapping polymers due to flow. A Smoluchowski equation is derived that includes these transient forces. From this, an equation of motion for the polymer number density is obtained, in which body forces couple the evolution of the polymer density to the local velocity field. Using a semimicroscopic Ansatz for the dynamics of the number of entanglements between overlapping polymers, and for the perturbations of the pair-correlation function due to flow, body forces are calculated for nonuniform systems where the density as well as the shear rate varies with position. Explicit expressions are derived for the shear viscosity and normal forces, as well as for nonlocal contributions to the body force, such as the shear-curvature viscosity. A contribution to the equation of motion for the density is found that describes mass transport due to spatial variation of the shear rate. The two coupled equations of motion for the density and flow velocity predict flow instabilities that will be discussed in more detail in a forthcoming publication.

Keyword(s): Hydrodynamics (MeSH) ; Models, Chemical (MeSH) ; Motion (MeSH) ; Polymers: chemistry (MeSH) ; Viscosity (MeSH) ; Polymers ; J

Note: We are grateful to J. Roovers for providing the star polymers used and to E. Stiakakis for assistance with characterization. This work was supported in part by the EU, NoE Soft-Comp (Grant No. NMP3-CT-2004-502235) and FP7 NanoDirect (Contract No. CP-FP-213948-2).

---

Contributing Institute(s):

1. Weiche Materie (ICS-3)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)

Appears in the scientific report 2011

---

Database coverage:
;

---