Construction of full-atomistic polymer amorphous structures using reverse-mapping from Kremer-Grest models

Area of Science:

• Polymer Science
• Computational Chemistry
• Materials Science

Background:

• Accurate construction of amorphous polymer structures is crucial for understanding material properties.
• Existing methods for generating full-atomistic (FA) polymer models can be computationally intensive and complex.
• Coarse-grained (CG) models offer a computationally efficient way to explore large-scale polymer behavior.

Purpose of the Study:

• To develop an efficient and accurate method for constructing full-atomistic (FA) amorphous polymer structures.
• To establish a sequential reverse-mapping strategy from abstract coarse-grained (CG) models to detailed FA models.
• To validate the proposed method by comparing generated structures with results from traditional FA molecular dynamics (MD) simulations.

Main Methods:

• Utilized a three-level modeling approach: CG1 (e.g., Kremer-Grest model), CG2 (monomer-level CG model), and FA model.
• Employed sequential reverse-mapping procedures: CG1 -> CG2 -> FA.
• Developed a specific mapping relation to ensure accurate density and chain radius in the FA model.
• Applied the scheme to polyethylene (PE), cis 1,4-polybutadiene (PB), and poly(methyl methacrylate) (PMMA).

Main Results:

• The developed scheme successfully constructed FA amorphous polymer structures for PE, PB, and PMMA.
• Validation against long-time FA MD simulations showed excellent agreement in both short- and long-range chain structures for PE and PB.
• The method efficiently generated an entangled PMMA structure, demonstrating its applicability to complex systems.

Conclusions:

• The proposed reverse-mapping method provides an efficient and accessible approach for building full-atomistic amorphous polymer structures.
• This technique bridges the gap between computationally efficient CG models and detailed FA representations.
• The validated scheme facilitates the generation of complex polymer architectures for further simulation and analysis.