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A Combined Scheme for Systematically Coarse-Graining of Stereoregular Polymer Blends

Wu, Chaofu
Macromolecules 2013 v.46 no.14 pp. 5751-5761
energy, molecular dynamics, poly(vinyl chloride), polymethylmethacrylate
A new computationally inexpensive scheme has been developed for deriving coarse-grained (CG) potentials of stereoregular polymers. In this scheme, from the constraint-distance stochastic dynamics (SD) simulations of trimer/trimer pairs in a vacuum, the nonbonded CG potentials are first parametrized by the conditional reversible work (CRW) method, which are then used to optimize the bonded CG potentials by the iterative Boltzmann inversion (IBI) method against the SD simulations of single-oligomer chains in a vacuum. This method is exemplarily applied to two technically important polymer blends composed of either isotactic or syndiotactic poly(methyl methacrylate) (iPMMA, sPMMA) and isotactic poly(vinyl chloride) (iPVC). Based on the molecular dynamics (MD) simulations with the so-derived CG potentials, detailed analyses on structural and energy properties suggest that the two studied mixtures are homogeneous. More critically, our simulations yield that sPMMA is more miscible with iPVC than is iPMMA, which reproduces the known experimental trends. From the dynamics analyses, the CG simulations also exhibit very high computational efficiency. Therefore, the so-developed CG scheme holds great promise in multiscale simulations of complex polymer systems.