Role of mapping schemes on dynamical and mechanical properties of coarse-grained models of cis-1,4-polyisoprene

We study and compare four coarse-grained models of cis-1,4-polyisoprene distinguished by mapping schemes for locating superatoms. First, coarse-grained potentials are obtained by iterative Boltzmann inversion method for the polymer melt. For all the coarse-grained models considered, time-scale factors based on translational and rotational motion were found to be different. However, coarse-grained potentials were unable to reproduce stress–strain behaviour of the underlying detailed model due to weak attractive nature of the nonbonded part of the coarse-grained potential. Consequently, the nonbonded potentials were optimized using particle swarm optimization to match the tensile behaviour of a detailed model of the polymer below glass transition temperature. While the modified potentials seemed to better predict the mechanical behaviour, the ability to accurately predict simultaneously the structural distributions also, depends on the mapping scheme.