title: Coarse-grained simulations of cis- and trans-polybutadiene: A bottom-up approach.
abstract: We apply the dissipative particle dynamics strategy proposed by Hijón et al. [Faraday Discuss. 144, 301-322 (2010)] and based on an exact derivation of the generalized Langevin equation to cis- and trans-1,4-polybutadiene. We prove that it is able to reproduce not only the structural but also the dynamical properties of these polymers without any fitting parameter. A systematic study of the effect of the level of coarse-graining is done on cis-1,4-polybutadiene. We show that as the level of coarse-graining increases, the dynamical properties are better and better reproduced while the structural properties deviate more and more from those calculated in molecular dynamics (MD) simulations. We suggest two reasons for this behavior: the Markovian approximation is better satisfied as the level of coarse-graining increases, while the pair-wise approximation neglects important contributions due to the relative orientation of the beads at large levels of coarse-graining. Finally, we highlight a possible limit of the Markovian approximation: the fact that in constrained simulations, in which the centers-of-mass of the beads are kept constant, the bead rotational dynamics become extremely slow.
authors.affiliation: Laboratoire de Chimie Physique, CNRS, Université Paris Sud, Bâtiment 349, 91405 Orsay Cedex, France.
authors.forename: Claire A
authors.initials: CA
authors.lastname: Lemarchand
authors.affiliation: Manufacture Française des Pneumatiques Michelin, Site de Ladoux, 23 Place des Carmes Déchaux, France Cedex 9, 63040 Clermont-Ferrand, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Couty
authors.affiliation: Laboratoire de Chimie Physique, CNRS, Université Paris Sud, Bâtiment 349, 91405 Orsay Cedex, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Rousseau