title: Multiscale modeling of polyisoprene on graphite.
abstract: The local dynamics and the conformational properties of polyisoprene next to a smooth graphite surface constructed by graphene layers are studied by a multiscale methodology. First, fully atomistic molecular dynamics simulations of oligomers next to the surface are performed. Subsequently, Monte Carlo simulations of a systematically derived coarse-grained model generate numerous uncorrelated structures for polymer systems. A new reverse backmapping strategy is presented that reintroduces atomistic detail. Finally, multiple extensive fully atomistic simulations with large systems of long macromolecules are employed to examine local dynamics in proximity to graphite. Polyisoprene repeat units arrange close to a parallel configuration with chains exhibiting a distribution of contact lengths. Efficient Monte Carlo algorithms with the coarse-grain model are capable of sampling these distributions for any molecular weight in quantitative agreement with predictions from atomistic models. Furthermore, molecular dynamics simulations with well-equilibrated systems at all length-scales support an increased dynamic heterogeneity that is emerging from both intermolecular interactions with the flat surface and intramolecular cooperativity. This study provides a detailed comprehensive picture of polyisoprene on a flat surface and consists of an effort to characterize such systems in atomistic detail.
authors: Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, USA.
authors: Yogendra Narayan
authors: YN
authors: Pandey
authors: Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, USA.
authors: Alexander
authors: A
authors: Brayton
authors: Global Materials Science Division, The Goodyear Tire & Rubber Company, Akron, Ohio 44305, USA.
authors: Craig
authors: C
authors: Burkhart
authors: Global Materials Science Division, The Goodyear Tire & Rubber Company, Akron, Ohio 44305, USA.
authors: George J
authors: GJ
authors: Papakonstantopoulos
authors: Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, USA.
authors: Manolis
authors: M
authors: Doxastakis
mesh_terms: D002070:Butadienes / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D045782:Hemiterpenes / Q000737:chemistry*; D008958:Models, Molecular; D009010:Monte Carlo Method; D010420:Pentanes / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; D011108:Polymers; C005059:isoprene; D006108:Graphite