Phase Behavior of Polymer Nanocomposites from Gravity-based Combinatorial Simulations

The phase behavior of polymers mixed with nanoparticles, termed nanocomposites, has been of great current interest. Holding the promise of improved engineering properties, the property improvement is critically dependent on the spatial dispersion of nanoparticles, which is controlled by polymer-nanoparticle phase behavior. Enumerating the appropriate phase diagrams, however, still remain outside the realm of most simulation-based methods. The difficulty arises since inserting a large particle into a dense sea of small particles, critically for establishing phase equilibrium, is prohibitively difficult. Here we extend a gravity-based combinatorial method, first devise by Biben et al., and used primarily in the context of pure fluids to circumvent this insertion issue. Our results are validated against available simulations for colloid mixtures, but provide new insight into the phase behavior of polymers and nanoparticles.