Comparison of Field-Theoretic Approaches in Predicting Polymer Nanocomposite Phase Behavior

The considerable parameter space associated with polymer nanocomposites (PNCs) requires efficient theoretical and simulation methods to understand their assembly and guide experiments. We directly compare field-based approaches for modeling PNCs, one equilibrium and one nonequilibrium method. We find that common approximations used in typical equilibrium field-based simulations of PNCs, such as the mean-field approximation or an evenly distributed graft site distribution, have a prominent impact on the large scale phase behavior of polymer nanocomposites in experimentally relevant regimes. The nonequilibrium method trivially circumvents these approximations while also providing analysis of nonequilibrium phenomena. The nonequilibrium method is compared to experiments consisting of polystyrene grafted gold nanorods in a poly(methyl methacrylate) matrix to ensure the model gives results that qualitatively agree with the experiments. Using this insight, we further implement these methods to study a more complex system, examining the brush structure and assembly of mixed brush nanoparticles in solution.