Shrinkage-expansion of a tri-isometric knitting from graphene ribbons at finite temperature

A model of two-dimensional knitting system is constructed from graphene ribbons (GRs) aligned in the three isometric directions. It then recommends a process for fabrication of the nanotexture. Based on the model, its thermal stability is assessed via molecular dynamics simulations. The nanotexture may experience out-of-plane fold or in-plane shrinkage at different temperatures due to the three factors including bending of the ribbons, relative sliding between the ribbons at their overlapping areas, and strong van der Waals forces between the GRs. In addition to the global deformation of the nanotexture, it has experienced local deformation at pores which depends on the chirality and gaps of the GRs. For a nanotexture formed from armchair GRs, it is relaxed to be a quasi-periodic porous medium with similar pore size. The mechanism is that the armchair GRs have non-smooth edges, and are locked at their contact areas in relative sliding. In water, the in-plane shrunk nanotexture does not expand to be a plate even at 500 K. However, in argon, it expands to be a plate with periodic hexagon pores. The proposed nanotexture may have significant applications in the area of controllable shrinkage-expansion oriented nanomaterial/nanodevice. Keywords: 2D nanoporous material, Nanotexture, In-plane shrinkage, Out-of-plane fold, Shrinkage-expansion control, Molecular dynamics