# A Transient Bond Model for Dynamic Constraints in Meso-Scale Coarse-Grained Systems

## TL;DR

This paper introduces a highly coarse-grained transient bond model for simulating the dynamic constraints in entangled polymers, effectively reproducing their viscoelastic and diffusion behaviors with simplified particles and bonds.

## Contribution

The paper develops a novel coarse-grained slip-spring model based on transient bonds that captures the dynamics of entangled polymers without affecting static properties.

## Key findings

- Model accurately reproduces viscoelastic behavior of entangled polymers
- Transient bonds influence dynamics but not static equilibrium properties
- Simulation results match experimental observations of polymer diffusion

## Abstract

The dynamical properties of entangled polymers originate from the dynamic constraints due to the uncrossability between polymer chains. We propose a highly coarse-grained simulation model with transient bonds for such dynamically constrained systems. Based on the ideas of the responsive particle dynamics (RaPiD) model [P. Kindt and W. J. Briels, J. Chem. Phys. 127, 134901 (2007)] and the multi-chain slip-spring model [T. Uneyama and Y. Masubuchi, J. Chem. Phys. 137, 154902 (2012)], we construct the RaPiD type transient bond model as a coarse-grained slip-spring model. In our model, a polymer chain is expressed as a single particle, and particles are connected by transient bonds. The transient bonds modulate the dynamics of particles but they do not affect static properties in equilibrium. We show the relation between parameters for the entangled polymer systems and those for the transient bond model. By performing simulations based on the transient bond model, we show how model parameters affect the linear viscoelastic behavior and the diffusion behavior. We also show that the viscoelastic behavior of entangled polymer systems can be well reproduced by the transient bond model.