Developments in multichain coarse-grained models for entangled polymer dynamics

Abstract

This review describes the development and applications of multichain coarse-grained simulations for entangled polymer dynamics. The mean-field tube model has long served as the standard paradigm for describing the many-body entanglement problem as the motion of a single chain in a static field; it faces intrinsic limitations when spatial correlations, fluctuations, and complex topological rearrangements are addressed. To overcome these limitations, “multichain” approaches—specifically, the primitive chain network and multichain slip-spring models—were developed. These simulations explicitly resolve the force balance and topological coupling between multiple chains in three-dimensional space. This review covers the primitive chain network model, which emphasizes real-space force balance, and the multichain slip-spring model, which is derived from a well-defined free energy functional. Linear and nonlinear rheology predictions are discussed, along with molecular mechanisms such as constraint release and stretch/orientation-induced reductions in friction. Extensions to branched polymers, wall-slip phenomena, and network polymers are also mentioned. This review summarizes efforts to develop coarse-grained multichain models for entangled polymers. The studies aim to bridge an important gap between the standard bead-spring model and the tube model. The primitive chain network model is a multi-chain version of the tube-type description, whereas the multichain slip-spring model is a multichain entangled Rouse model. Both models reproduce entangled polymer dynamics at a lower computational cost than bead-spring simulations and straightforwardly account for complex multi-chain correlations that tube models capture via the mean-field approach.