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Multiscale Simulation of Soft Matter

In computational modeling of soft matter one is confronted with a variety of time- and length-scales. At the atomistic scale, vibration of chemical bonds occurs at time- and length-scales in the order of femtoseconds and Ångstroms, respectively. However, the structural relaxation of polymers usually needs much longer time scales, not achievable in atomistic simulations. Therefore, in the past decades, there has been a rapid development on the advent of multiscale simulation models that make it possible to bridge the gap between the purely atomistic and macroscopic descriptions. However, an important issue in the development of such multiscale models is to build the coarser model based on the information obtained from systems of smaller size at finer level. In this respect, multiscale simulation methods systematically combine a broad range of length- and time-scales and are able to address phenomena at multiple levels of resolution.

The aim of this workshop is to consolidate and discuss the progress in this multidisciplinary research field from both scientific and practical perspectives. To this aim, the following subjects will be covered in the workshop.

I.  Construction of systematic structure-based coarse-grained simulation models which are connected to the atomistic resolution level. These models encompass a variety of soft matter problems, ranging from structure-formation in amorphous polymers to biomolecular aggregation.

II.   The route back from the coarse-grained level to atomistic level (back mapping), which is important for generating well-equilibrated long polymer chains.

III.  Bridging the gap between atomistic and mesoscopic time- and length-scales. In prediction of the mesoscopic structure of polymer, a mesoscopic method, like dissipative particle dynamics (DPD) simulation, is required. However, to keep the atomistic level information, molecular fragments are simulated atomistically to derive the DPD parameters. This link opens the way to do large scale simulations, to study the formation of micelles, networks, mesophases and so on.

 IV.  Hybrid methods. In some applications of polymers, for example when the polymer is in contact with a surface, the molecular details are important only in a small spatial region, and the rest of the system can be considered by continuum mechanics. For such applications, it is convenient to develop a hybrid method, in which the region of interest is simulated at atomistic level, but the rest of the system is treated by continuum mechanics methods.

V. Construction of dynamic coarse-grained models. Although multiscale models accurately describe equilibrium structural properties, the dynamics gets artificially accelerated in all coarse-grained models. To study the dynamical properties of the system, it is necessary to introduce drift terms to capture the full dynamics of the coarse-grained model.

VI.  Inclusion of electrostatic interactions in the multiscale models. As electrostatics plays a key role in the interactions of both atomistic and multiscale models, in development of coarse-grained models for charged systems an adequate consideration of long-range electrostatic interactions is important and significantly affects the collective properties of the materials. 

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