We probe the influence of branching on the thermodynamic, packing, and structural properties of polymer melts of linear chains and model branched (star, unknotted rings, bottlebrush) polymers with the use of coarse-grained molecular dynamics simulations of branched polymer melts with emphasis on molecular masses larger than the entanglement molecular mass of linear chains. In particular, we calculate the conformational properties of these polymers, such as the hydrodynamic radius Rh , the packing length, and the polymer center of mass self-diffusion coefficient, D. Our simulation results reproduce the phenomenology of entangled linear chains and branched polymers, and we attempt to understand our observations. Since a unifying framework describing D for different types of molecular architectures is not available, we introduce a model of entanglement phenomenon of high molecular mass polymers to arise from the emergence of heterogeneous dynamics similar to glass-forming liquids. Based on this novel perspective of polymer melt dynamics, we propose a functional form for D that can describe from unentangled to entangled regimes for linear chains, and well as, star polymer melts.
entanglements, polymers, stars