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Structure, surface excess and effective interactions in polymer nanocomposite melts and concentrated solutions
J B Hooper1, K S Schweizer, T G Desai
1Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, USA.
The Journal of Chemical Physics
|October 12, 2004
Summary
Polymer Reference Interaction Site Model (PRISM) theory reveals how polymer-particle interactions drive dewetting and depletion forces. These forces transition from attractive to oscillatory, with particle size influencing universal force behavior.
Area of Science:
- Soft Matter Physics
- Polymer Science
- Computational Chemistry
Background:
- Dense polymer-particle mixtures exhibit complex phase behavior and interactions.
- Understanding interparticle forces is crucial for controlling material properties.
Purpose of the Study:
- Investigate structure, effective forces, and thermodynamics in dense polymer-particle mixtures.
- Quantify polymer-induced depletion interactions and their dependence on system parameters.
- Explore the impact of monomer-particle attractions on interface and interaction behavior.
Main Methods:
- Utilized Polymer Reference Interaction Site Model (PRISM) theory.
- Employed spatially nonlocal hypernetted chain closure for correlations.
- Validated PRISM calculations with molecular dynamics simulations.
Main Results:
- Identified entropic dewetting at the interface in the athermal limit.
- Observed a transition in depletion forces from attractive to oscillatory near the semidilute-concentrated boundary.
- Demonstrated a near-universal collapse of depletion forces for large particles.
- PRISM theory accurately captured simulation results for depletion forces.
Conclusions:
- PRISM theory is a powerful tool for predicting polymer-particle mixture behavior.
- Particle size significantly influences depletion force universality.
- Monomer-particle attractions can drive wetting and lead to diverse interaction behaviors.