Dispersing Nanofillers and Tuning Their Interfaces with Matrix Polymers in Nanocomposites: A Molecular Dynamics Perspective

To fulfill the potential of polymer nanocomposites, a key challenge is to achieve the synergy between nanofillers and matrix polymers. To this end, the dispersion state of the nanofillers in the composites and their interfaces with the host polymers must be optimized. Extensive molecular dynamics simulations show that grafting two-dimensional nanofillers with polymers enhances their dispersion in polymer matrices and improves the matrix-nanofiller compatibility and interaction strength at the interface. Using polyetherimide-graphene nanocomposites as a model system, the simulations echo experimental observations and provide molecular scale rationale for the enhanced mechanical properties of the nanocomposites. Furthermore, nonequilibrium processes and effects such as fast solvent evaporation are exploited to better disperse nanofillers in polymers even when the interactions between the two are unfavorable. The simulations provide useful guidance on future work of fabricating and optimizing polymer nanocomposites.