  Graphene, one of the strongest materials ever discovered, triggered the
exploration of many 2D materials in the last decade. However, the successful
synthesis of a stable nanomaterial requires a rudimentary understanding of the
relationship between its structure and strength. In the present study, we
investigate the mechanical properties of 8 different carbon-based 2D
nanomaterials by performing extensive density functional theory calculations.
The considered structures were just recently either experimentally synthesized
or theoretically predicted. The corresponding stress-strain curves and elastic
moduli are reported. They can be useful in training force field parameters for
large scale simulations. A comparative analysis of these results revealed a
direct relationship between atomic density per area and elastic modulus.
Furthermore, for the networks that have an armchair and a zigzag orientation,
we observed that they were more stretchable in the zigzag direction than the
armchair direction. A critical analysis of the angular distributions and radial
distribution functions suggested that it could be due to the higher ability of
the networks to suppress the elongations of the bonds in the zigzag direction
by deforming the bond angles. The structural interpretations provided in this
work not only improve the general understanding of a 2D material's strength but
also enables us to rationally design them for higher qualities.
