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ORAL PRESENTATION
Session: 2 Multiscale modeling and molecular simulations
(scheduled: Monday, 09:40 )
Hierarchical Modeling of Polystyrene: From Atomistic to Coarse-Grained Simulations
V. Harmandaris, N. van der Vegt, K. Kremer
Max-Planck-Institute for Polymer Research, D-55021 Mainz, Germany
We present a hierarchical approach that combines atomistic and mesoscopic simulations which can generally be applied to vinyl polymers. As a test case the approach is applied to atactic polystyrene (PS). First a specific model for atactic PS is chosen. The bonded parameters in the coarse-grained force field, based on data obtained from atomistic simulations of isolated PS dimers, are chosen in a way which allows to differentiate between meso- and racemic dyads. This approach allows to study isotactic and syndiotactic melts. Nonbonded interactions between coarse-grained beads were chosen as purely repulsive. The proposed mesoscopic model reproduces both the local structure and the chain dimensions properly. An explicit time mapping is performed, based on the atomistic and CG mean square displacements of short chains, demonstrating an effective speed up of about three orders of magnitude compared to brute force atomistic simulations. Finally the equilibrated coarse-grained chains are back mapped onto the atomistic systems. This opens new routes for obtaining well equilibrated high molecular weight polymeric systems and also providing very long dynamic trajectories at the atomistic level for these polymers. © IWNET 2006
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and Kleanthi for IWNET 2006