Mechanical behavior of graphene quantum dot epoxy nanocomposites: A molecular dynamics study

•Molecular dynamics simulated graphene quantum dot (GQD) epoxy nanocomposites.•GQDs with amines enhance epoxy yield strength by 17% and stiffness by 6%.•Pristine GQDs reduce epoxy yield strength and stiffness.•Epoxy covalently bonds to aminated GQDs to increase load transfer. Quantum dot fillers were reported to enhance stiffness, yield strength, and toughness of polymers. However, the underlying mechanisms for these enhancements are unclear. In this study, for the first time, molecular dynamics simulations were performed to reveal the effects of graphene quantum dots (GQDs) on epoxy properties. Mechanical simulations revealed that addition of a single-layer graphene quantum dot with six reactive amine groups enhanced the epoxy yield strength by 17% and stiffness by 6%; whereas pristine GQDs reduced the strength by 6% and stiffness by 10%. The results show the importance of surface chemistry of GQDs towards the intelligent design of strong, tough, and multifunctional nanocomposites.