Molecular structure data and modelling roadmap for optimized oxidized graphene quantum dot and epoxy interface and mechanical properties

Hybrid epoxy composites are highly considered for low-density applications due to the excellent specific strength and specific stiffness. Enhancements made to the epoxy matrix by addition of nanofillers like carbon nanotubes (CNTs) and graphene (GNPs) have been studied in detail over the course of few decades. These enhancements not only help elevate the material properties of the matrix but also activate different failure mitigating mechanisms in the composite. Although highly beneficial, there are few shortcomings due to the challenging fabrication process of integrating such. Common problems like filler agglomeration, formation of voids, wrinkling and more can result in poor load transfer within the composite. Graphene quantum dots (GQDs), on the other hand are the smallest carbon-based filler which are known to promote more intimate contact with the matrix. Their small size enables simultaneous enhancement of stiffness, strength and toughness. In addition, functionalization of these materials enables other supramolecular interactions like hydrogen bonding which improve the interfacial interaction with the epoxy. This study provides a molecular dynamics (MD) workflow to model a single functionalized GQD embedded in an epoxy matrix and the effective mechanical response of the nanocomposite. Ten chemistries were developed with different oxygen-based functional groups which capture the effect of GQD on the mechanical properties of the nanocomposite. Uniaxial strain simulations revealed that a maximum strength gain of 56 % and stiffness gain of 18 % was computed by the oxidized GQD-epoxy nanocomposite.