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Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
Length-scale dependent relaxation shear modulus and viscoelastic hydrodynamic interactions in polymer liquids
A N Semenov1, J Farago, H Meyer
1Institut Charles Sadron, CNRS-UPR 22, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France.
The Journal of Chemical Physics
|July 5, 2012
Summary
This study presents a quantitative theory for polymer hydrodynamic interactions, revealing they persist at large distances and are independent of molecular mass in pre-Rouse regimes. Viscoelastic effects significantly influence these interactions, leading to unique transient behaviors.
Area of Science:
- Polymer Physics
- Soft Matter Physics
- Rheology
Background:
- Hydrodynamic interactions are crucial in polymer dynamics.
- Understanding transient regimes (pre-Rouse) is key to polymer melt and solution behavior.
- Viscoelastic effects dominate hydrodynamic responses at short times.
Purpose of the Study:
- To develop a quantitative theory for hydrodynamic interactions in unentangled polymer melts and concentrated solutions.
- To investigate the pre-Rouse transient time regimes.
- To elucidate unusual transient regimes of hydrodynamic response functions.
Main Methods:
- Development of a quantitative theoretical framework.
- Analysis of viscoelastic effects on hydrodynamic interactions.
- Characterization of regimes using characteristic times (momentum spreading and viscoelastic times).
Main Results:
- Transient viscoelastic hydrodynamic interactions are not screened at large distances and are independent of polymer molecular mass.
- Unusual and qualitatively different transient regimes for isotropic and anisotropic hydrodynamic responses were identified.
- Effective viscosity, dependent on time and length scale, can be significantly lower than macroscopic viscosity in certain regimes.
Conclusions:
- The theory provides a quantitative description of hydrodynamic interactions in pre-Rouse regimes.
- Viscoelasticity plays a dominant, non-screening role in long-range hydrodynamic interactions.
- The findings offer insights into stress relaxation and effective viscosity in polymer systems.
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