Mesoscale modeling of shear-thinning polymer solutions

Area of Science:

• Polymer Physics
• Rheology
• Computational Materials Science

Background:

• Viscoelastic polymer solutions exhibit complex flow behaviors.
• Existing coarse-grained models like Responsive Particle Dynamics (RaPiD) struggle to capture nonlinear rheology.
• The spherical particle representation in RaPiD limits its predictive power for complex polymer dynamics.

Purpose of the Study:

• To improve the Responsive Particle Dynamics (RaPiD) model for simulating polymer solution rheology.
• To investigate the impact of particle deformability on capturing nonlinear rheological phenomena.
• To achieve accurate prediction of experimental rheological data for polymer solutions.

Main Methods:

• Simulation of polyisobutylene in pristane and hydroxypropylcellulose in water using a modified RaPiD model.
• Introduction of deformable particles with Finite-Extensible Non-Linear Elastic (FENE) potential to penalize elongation.
• Comparison of simulation results with experimental linear and nonlinear rheology data.

Main Results:

• The extended RaPiD model with deformable particles accurately reproduces experimental nonlinear rheology.
• Particle deformability, specifically maximum elongation, is critical for capturing nonlinear viscoelastic behavior.
• The model retains accurate predictions for linear rheology while enhancing nonlinear predictions.

Conclusions:

• Particle deformability is essential for coarse-grained models to accurately predict nonlinear polymer solution rheology.
• The modified RaPiD model provides a robust framework for simulating complex viscoelastic fluids.
• This approach offers a pathway to better understand and predict polymer dynamics under flow.