Holes interaction of a graphene membrane under pressure for water desalination

Abstract

Single-layer graphene is the basic structural element of several carbon allotropes, including graphite, fullerens and carbon nanotubes. The mechanical behavior of graphene has been intensely studied in the last years and it has been shown that it is significantly affected by the presence of structural holes, e.g., atom vacancies in the graphene lattice, which can dramatically reduce the failure strength. The presence of holes in the graphene lattice is nearly inevitable, either because of the production process or because of the environmental and operating conditions of the devices. Moreover, in some engineering applications, such as the desalination of sea water through a graphene filter, atom vacancies could be deliberately introduced to achieve new functionalities. Hence, the interaction between multiple holes becomes extremely important for the overall mechanical properties in a single-layer graphene. Here, we study the mechanical behavior of perforated single-layer graphene membrane through a molecular mechanics model, which is solved numerically using the Riks arc length method. We show that the distance between multiple holes in tensile tests determines a very different failure strength of the single-layer graphene. Finally, the effect of holes is also investigated in the case of out of plane deformation. Such analysis lays the foundations for the development of more sophisticated nano-materials that can achieve non-trivial mechanical functionalities through the presence of holes.