Constrained Low-Dimensional Parametrization of Coarse-Grained Force Fields for Structural and Thermodynamic...

Area of Science:

• Materials Science
• Computational Chemistry
• Chemical Engineering

Background:

• Coarse-grained (CG) molecular dynamics often faces challenges in maintaining both structural accuracy and thermodynamic consistency for complex multicomponent condensed-phase systems.
• Accurate modeling of systems like asphalt is crucial for understanding their behavior and properties.

Purpose of the Study:

• To develop and validate a hierarchical hybrid, closed-loop parametrization strategy for CG molecular dynamics.
• To improve the structural fidelity and thermodynamic consistency of CG simulations for complex condensed-phase systems, using base asphalt as a model.

Main Methods:

• Iterative Boltzmann Inversion (IBI) for deriving bonded interactions with robust statistical treatment.
• Utilizing the Martini 3 framework for non-bonded interactions, calibrated with global scaling factors and geometric fine-tuning.
• Hierarchical hybrid, closed-loop parametrization strategy for force field development.

Main Results:

• The developed CG model accurately reproduces the density-temperature response and key structural statistics compared to all-atom (AA) simulations.
• The model preserves relative component diffusion rankings and enables consistent time rescaling to AA references.
• Mesoscale simulations capture asphaltene self-aggregation, aromatic-core stacking, and experimentally observed bee-like morphologies.

Conclusions:

• The proposed strategy offers a reproducible and parsimonious paradigm for constructing CG force fields in complex mixtures.
• This method enables the coupled convergence of structure and thermodynamics in CG simulations.
• The validated model advances the capability of CG molecular dynamics for complex materials like asphalt.