Stochastic entangled chain dynamics of dense polymer solutions

Demosthenes Kivotides, S. Louise Wilkin, Theo G. Theofanous

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

We propose an adjustable-parameter-free, entangled chain dynamics model of dense polymer solutions. The model includes the self-consistent dynamics of molecular chains and solvent by describing the former via coarse-grained polymer dynamics that incorporate hydrodynamic interaction effects, and the latter via the forced Stokes equation. Real chain elasticity is modeled via the inclusion of a Pincus regime in the polymer's force-extension curve. Excluded volume effects are taken into account via the combined action of coarse-grained intermolecular potentials and explicit geometric tracking of chain entanglements. We demonstrate that entanglements are responsible for a new (compared to phantom chain dynamics), slow relaxation mode whose characteristic time scale agrees very well with experiment. Similarly good agreement between theory and experiment is also obtained for the equilibrium chain size. We develop methods for the solution of the model in periodic flow domains and apply them to the computation of entangled polymer solutions in equilibrium. We show that the number of entanglements Π agrees well with the number of entanglements expected on the basis of tube theory, satisfactorily reproducing the latter's scaling of Π with the polymer volume fraction φ. Our model predicts diminishing chain size with concentration, thus vindicating Flory's suggestion of excluded volume effects screening in dense solutions. The predicted scaling of chain size with φ is consistent with the heuristic, Flory theory based value.

LanguageEnglish
Article number144903
Number of pages10
JournalJournal of Chemical Physics
Volume133
Issue number14
DOIs
Publication statusPublished - 14 Oct 2010

Fingerprint

Polymer solutions
Polymers
polymers
Elasticity
Dynamic models
Volume fraction
Screening
Hydrodynamics
Experiments
scaling
molecular chains
dynamic models
suggestion
screening
elastic properties
hydrodynamics
inclusions
tubes
curves

Keywords

  • entangled chain dynamics model
  • dense polymer solutions
  • polymer dynamics

Cite this

Kivotides, Demosthenes ; Wilkin, S. Louise ; Theofanous, Theo G. / Stochastic entangled chain dynamics of dense polymer solutions. In: Journal of Chemical Physics . 2010 ; Vol. 133, No. 14.
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Stochastic entangled chain dynamics of dense polymer solutions. / Kivotides, Demosthenes; Wilkin, S. Louise; Theofanous, Theo G.

In: Journal of Chemical Physics , Vol. 133, No. 14, 144903, 14.10.2010.

Research output: Contribution to journalArticle

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