Potential Universal Extensional Rheology in Concentrated Polymeric Liquids
(2024) Macromolecules — Vol. 57, n° 11, p. 5520-5532 (2024)
Files
Jiang-2024-PotentialUniversalExtensionalRhe.pdf
Open Access - Adobe PDF
- 4.38 MB
Details
- Authors
- Abstract
- Polymer dynamics are special in that they are always insensitive to the chemical details of the monomers. However, the recent experiments show that the nonlinear extensional rheology of concentrated polymeric liquids has a non-universal feature. In this work, the variations of inter-chain interaction under flows in coarse-grained (CG) molecular dynamics (MD) simulations of polymer melts are investigated in terms of the frictional coefficient, which is thought to be the critical factor in explaining the observed non-universality. The frictional coefficients in the simulations are quantified from the expressions we proposed very recently (Jiang, N.; van Ruymbeke, E., Macromolecules 2023, 56 (8), 2911-2929.), which are based on the analytical relationships between the frictional coefficient and the observable quantities. After the validation of the simulations with experimental data and our expressions, it is shown that those frictional coefficients can be universally related to the projection areas of the polymer coils. Moreover, this projection-friction relationship indicates a Kuhn-scale criterion of extensional viscosity, which suggests similar extensional rheology will be observed when the materials have the same number of Kuhn segments per chain N_k and the same reduced density n_k defined as the ratio of the Kuhn length to the packing length. This criterion is tested on a series of new simulation systems designed to show similar steady-state extensional viscosities as a function of the reduced extensional rate, as well as the existing experimental data in the literature. The results of this work provide a helpful guideline in searching for the potential universal extensional rheology in the experimental samples.
- Affiliations
Citations
Jiang, N. (2024). Potential Universal Extensional Rheology in Concentrated Polymeric Liquids. Macromolecules, 57(11), 5520-5532. https://doi.org/10.1021/acs.macromol.3c02648 (Original work published 2024)