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Coarse-grained molecular simulations.
Few representative publications: 1) Bedrov, D.; Smith, G.D.; Li.L.; “A Molecular Dynamics Simulation Study of the Role of Evenly-spaced Poly(ethylene oxide) Tethers on the Aggregation of C60 Fullerenes in Water”, Langmuir, 2005, 21, 5251-5255 . 2) J.B. Hooper, D Bedrov, and G.D. Smith, “Supramolecular Self-organization in PEO-modified C60 Fullerene/Water Solutions: Influence of Polymer Molecular Weight and Nanoparticle Concentration” Langmuir, 2008, 24, 4550. 3) Bedrov, D.; Smith, G.D., Smith, J.S. “ Matrix-induced Nanoparticle Interactions in Polymer Melts. A Molecular Dynamics Simulation Study” J. Chem. Phys. 2003, 119, 10438-10447. 4) Bedrov, D.; Ayyagari, C.; Smith, G.D.; “Multiscale Modeling of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Copolymer Micelles in Aqueous Solution” J. Chem. Theory & Comput. 2006, 2, 598-606.
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As the parameter space explorable by simulations using atomistically-detailed models is limited by computational demands, computationally faster coarse-grained models are often utilized in which each interaction site can be designed to represent several atoms (e.g., a monomer) or even several monomers (e.g., a polymer statistical segment). The main challenge in parameterizing such models is to effectively capture the local structure, conformations and specific interactions operative in the real system. Parameterization of coarse-grained models can be significantly simplified and even automated if results from simulations using accurate atomistically-detailed model are available for the same system. In this case, structural and conformational correlations obtained from limited simulations using atomistic models provide data to optimize parameters of the coarse-grained model to adequately reproduce all important features in the system. For example, we have developed a coarse-grained implicit solvent model for C60 fullerenes tethered by six PEO oligomers [(PEO)6-C60] in aqueous solutions. This model represents each C60 and each PEO monomer as a single force center, while water was treated implicitly. The model has been parameterized to reproduce thermodynamic, structural and conformational properties obtained for equivalent systems using atomistic MD simulations. Using the parameterized coarse-grained model we have extensively studied the self-association behavior of the polymer-grafted fullerenes (as illustrated on the figure) in systems containing 1000 (PEO)6-C60 fullerenes, which would be computationally impossible for the atomistic MD simulations.