Mechanical properties of methyl functionalized graphene: a molecular dynamics study

Molecular dynamics simulations have been performed to study the mechanical properties of methyl (CH3) functionalized graphene. It is found that the mechanical properties of functionalized graphene greatly depend on the location, distribution and coverage of CH3 radicals on graphene. Surface functionalization exhibits a much stronger influence on the mechanical properties than edge functionalization. For patterned functionalization on graphene surfaces, the radicals arranged in lines perpendicular to the tensile direction lead to larger strength deterioration than those parallel to the tensile direction. For random functionalization, the elastic modulus of graphene decreases gradually with increasing CH3 coverage, while both the strength and fracture strain show a sharp drop at low coverage. When CH3 coverage reaches saturation, the elastic modulus, strength and fracture strain of graphene drop by as much as 18%, 43% and 47%, respectively.