Kremer-Grest models for commodity polymer melts: Linking theory, experiment and simulation at the Kuhn scale

TL;DR

This paper demonstrates how tuning chain stiffness in the Kremer-Grest polymer model enables accurate simulation of real commodity polymer melts at the Kuhn scale, linking theory, experiment, and simulation.

Contribution

It provides mapping relations from KG units to SI units for various polymers, enhancing the model's applicability to real-world systems.

Findings

Good agreement between simulated and experimental entanglement moduli.

Kuhn scale mapping captures universal large-scale polymer behavior.

Model tuning allows for realistic representation of commodity polymers.

Abstract

The Kremer-Grest (KG) polymer model is a standard model for studying generic polymer properties in Molecular Dynamics simulations. It owes its popularity to its simplicity and computational efficiency, rather than its ability to represent specific polymers species and conditions. Here we show, that by tuning the chain stiffness it is possible to adapt the KG model to model melts of real polymers. In particular, we provide mapping relations from KG to SI units for a wide range of commodity polymers. The connection between the experimental and the KG melts is made at the Kuhn scale, i.e. at the crossover from chemistry-specific small scale to the universal large scale behavior. We expect Kuhn scale-mapped KG models to faithfully represent universal properties dominated by the large scale conformational statistics and dynamics of flexible polymers. In particular, we observe very good agreement between entanglement moduli of our KG models and the experimental moduli of the target polymers.