Many-body interactions and coarse-grained simulations of structure of nanoparticle-polymer melt mixtures

We present a computational approach for coarse-grained simulations of nanoparticle-polymer melt mixtures. We first examine the accuracy of an effective one-component approach based on a pair interaction approximation to polymer-mediated interactions, and demonstrate that even at low particle volume fractions, the polymer-mediated many-body interaction effects can prove significant in determining the structural characteristics of mixtures of nanoparticles and polymer melts. The origin of such effects is shown to arise from the extent of polymer perturbations resulting from the presence of the nanoparticles. To account for such effects, we propose a new simulation approach that employs a coarse-grained representation of the polymers to capture the many-body corrections to the polymer-mediated pair interaction potentials. The results of the coarse-grained simulations are shown to be in good quantitative agreement with the reference simulations. The method developed in this article is proposed as a tractable approach to coarse-grain and effect computer simulations of atomistic descriptions of polymer-nanoparticle systems.