Diamond nanothreads as novel nanofillers for cross-linked epoxy nanocomposites

Abstract

The recently synthesized novel 1D diamond nanothreads (DNTs) have been reported to possess excellent mechanical property and may act as extraordinary new reinforcements for polymer-matrix nanocomposites. By performing a series of molecular dynamics simulations of cross-linked epoxy nanocomposites, the presence of DNTs are found to provide a remarkable improvement in the mechanical property of DNTs/epoxy nanocomposites, yielding an increase of ∼33% in tensile modulus compared with neat epoxy resin. Interestingly, a moderate aggregation of DNTs enables better enhancement in the tensile modulus, which contradicts to common notion that aggregation of nanofillers usually causes a severe deterioration on the mechanical property of nanocomposites. This encouraging reinforcing mechanism mainly stems from two aspects: 1) aggregated DNTs cause a less deterioration to the tensile modulus of cross-linked epoxy network than uniformly dispersed DNTs, and 2) aggregated DNTs enable a higher reinforcing efficiency along the loading direction owing to their straight structure arising from their relatively high bending rigidity. Moreover, the mechanical property of DNTs/epoxy nanocomposites can be further enhanced through the DNTs' functionalization because of improved load transfer capability across DNT/matrix interface. Our results suggest that DNTs are truly attractive reinforcement and may provide valuable design guidelines for high performance nanocomposites applications.