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.