Two- and three-body interactions among nanoparticles in a polymer melt

Area of Science:

• Computational materials science
• Polymer physics
• Nanotechnology

Background:

• Polymer nanocomposites offer enhanced material properties.
• Accurate modeling of nanoparticle interactions is crucial for predicting material behavior.
• Existing models often simplify inter-particle forces, potentially limiting predictive power.

Purpose of the Study:

• To directly calculate two- and three-body interactions in polymer nanocomposites using three-dimensional density functional theory (DFT).
• To compare DFT-derived potentials of mean force with those from polymer reference interaction site model (PRISM) theory.
• To assess the significance of three-body interactions and their impact on modeling polymer nanocomposites.

Main Methods:

• Direct three-dimensional density functional theory (DFT) calculations.
• Modeling nanoparticles as hard spheres within a hard-sphere homopolymer melt of freely jointed chains.
• Utilizing self-consistent polymer reference interaction site model (PRISM) theory for comparison.

Main Results:

• DFT calculations of two-particle potentials of mean force closely matched PRISM theory results.
• Significant three-body interactions between nanoparticles were identified.
• Two-body interactions alone were found to be inadequate for describing the system.

Conclusions:

• Three-body interactions play a crucial role in polymer nanocomposites.
• Accurate modeling requires accounting for these higher-order interactions.
• Simple pairwise potentials are insufficient for capturing the complex physics of these systems.