Hossein Ali Karimi-Varzaneh

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A technique to prepare well-equilibrated polymer melts is presented. The method, named fine-graining, consists of two steps: the generation of continuum random walks characterized by different Kuhn lengths and the insertion of the atomistic units on the "parent" random walk chains. The procedure ensures a good equilibration at long as well as short(More)
Based on a mesoscale model developed recently for polyamide-66, here we present a simple algorithm for reinserting the atomistic details neglected in the coarse-grained (CG) description. The resulting CG and detailed models are tested successfully against several structural properties including the number of hydrogen bonds (HBs). From a quantitative(More)
IBIsCO is a parallel molecular dynamics simulation package developed specially for coarse-grained simulations with numerical potentials derived by the iterative Boltzmann inversion (IBI) method (Reith et al., J Comput Chem 2003, 24, 1624). In addition to common features of molecular dynamics programs, the techniques of dissipative particle dynamics (Groot(More)
The physical phenomena and properties of macromolecules such as polymers or biological materials cover a wide range of length and time scales: from Ångströms and subpicoseconds to millimeters and minutes. Multiscale simulation methods link different computer simulation approaches, which cover these scales and the respective levels of resolution. Different(More)
This review provides an overview of the various coarse-grained models that have been developed in the past few years for amorphous polystyrene. Different techniques to develop the force fields and different mapping schemes lead to models that perform differently depending on the properties investigated. This review collects and compares the models to guide(More)
We present an effective and simple multiscale method for equilibrating Kremer Grest model polymer melts of varying stiffness. In our approach, we progressively equilibrate the melt structure above the tube scale, inside the tube and finally at the monomeric scale. We make use of models designed to be computationally effective at each scale. Density(More)
A coarse-grained ionic liquid model has been developed to investigate the structure and dynamic properties of 1-n-alkyl-3-methylimidazolium hexafluorophosphate [C(n)mim][PF(6)] ionic liquids with alkyl chains up to ten carbon atoms. Two mapping schemes are compared, showing that different ways of grouping the atoms into coarse-grained beads affect(More)
A scheme is described for performing molecular dynamics simulations on polymers under nonperiodic, stochastic boundary conditions. It has been designed to allow later the embedding of a particle domain treated by molecular dynamics into a continuum environment treated by finite elements. It combines, in the boundary region, harmonically restrained particles(More)
Rolling resistance ranks among the top ten automobile megatrends, because it is directly linked to fuel efficiency and emissions reduction. The mechanisms controlling this phenomenon are hidden deeply inside the complexity of tire tread materials and do elude direct experimental observation. Here we use atomistic molecular modelling to identify a novel(More)
Molecular dynamics simulations are performed to determine the solubility and diffusion coefficient of carbon dioxide and nitrogen in poly(methyl methacrylate) (PMMA). The solubilities of CO2 in the polymer are calculated employing our grand canonical ensemble simulation method, fixing the target excess chemical potential of CO2 in the polymer and varying(More)