Enhanced ImpactResistance in Multilayered Polymer–GrapheneNanocomposites via Confinement

Understanding energy dissipation at the nanoscale is crucial for developing advanced materials for impact resistance. Inspired by nature, multilayered polymer nanocomposites offer the possibility of lightweight enhanced energy dissipation. However, the performance of polymer nanocomposites is driven by molecular structure–property relationships that are not well understood, particularly the role of the interface and confinement between disparate materials. In this work, multimillion-atom reactive molecular dynamics (MD) simulations are conducted to investigate the supersonic and hypersonic impact, penetration, and failure response of multilayered polymer–graphene composites. Polyethylene (PE) and polystyrene (PS) thin films are layered with a bilayer graphene (G) membrane on the front and/or back face(s) and are compared for their energy dissipation capacity. Different regimes of energy dissipation are identified as the projectile penetrates each layer and are shown to depend on the layup configuration and impact velocity. Graphene on the front face (relative to the impact) of the polymer provides the greatest energy dissipation at and near the ballistic limit (<i>V</i>_bl). However, at impact velocities above <i>V</i>_bl, graphene added to the back side of the polymer films exhibits the largest energy dissipation, up to 37% larger than other configurations within the range of velocities studied. Back side confinement provided by the graphene layer drastically increases the internal pressure during impact and promotes chain scission over chain pullout, correlating to increased energy dissipation. The results indicate that multilayered nanomaterials can be designed for enhanced impact resistance in various dynamic environments.