Reactive coarse-grained molecular dynamics simulations of nanoparticle/polymer nanocomposites

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The growing technological need for novel high-performance materials imposes major challenges on today’s materials scientist. Synthetic nanocomposites are increasingly used in conditions where extreme mechanical loads have to be withstood. In the design of such materials, computer simulation techniques are becoming inevitable thanks to recent developments of modeling techniques and computational capacities. However, when it comes to predicting nanocomposite properties, current techniques fall short either of considering large enough systems (i.e. atomistic simulations) or accounting for the right underlying physics (i.e. continuum mechanics). In this ambitious project, which lies at the nexus of physics, chemistry and engineering, we propose a solution to these issues. Here, we put forward a novel multiscale simulation protocol based on adapting and improving some existing techniques to develop coarse-grained models for nanoparticle reinforced polymer nanocomposites. The characterizing feature of this project is to derive reactive coarse-grained force fields using a mapping procedure from all-atom molecular dynamics simulations. It allows simulations of large atomistic systems with an accurate description of the breaking of chemical bonds, which is indispensable to model damage mechanisms in the composite materials. The proposed methodology will be applied to an epoxy reinforced with boehmite nanoparticles, which have shown promising results as nanofillers. We will demonstrate the strength of the coarse-grained force fields in predicting the material properties in representative volume elements as a function of the most typical synthesis variables, such as the degree of polymer matrix crosslinking, filler content, and size and distribution of fillers. This project will also conclude with a general set of model development rules, laying the groundwork for coarse-grained simulations to become a major computational tool in the design of future nanocomposites.