An annealing approach to form a nanotube from graphdiyne ribbon: a theoretical prediction

A precisely controllable heat treatment process is critical for nanofabrication. We developed a two-step method to fabricate a graphdiyne nanotube (GNT) through heat treatment in an argon environment. Initially, we placed a carbon nanotube (CNT) near a rectangular graphdiyne nanoribbon (GNR) to trigger the self-scrolling of the ribbon. Once the ribbon forms a scroll, we increased the ambient temperature to induce the formation of interlayer covalent C-C bonds within the scroll, ultimately resulting in a GNT after system annealing. The self-scrolling process of the GNR, protected by argon gas, is highly sensitive to ambient temperature. Molecular dynamics simulations show that self-scrolling can be controlled by adjusting the gas density and/or ambient temperature. In summary, a controlled heating process starting from an ultralow temperature initiates the self-scrolling of a GNR onto a CNT, followed by the generation of covalent bonds within the GNR at higher temperatures. Since the new covalent bond topology remains stable even after cooling, a stable GNT is obtained. The size of the pores on the GNT shell depends on the number of newly formed bonds. These insights will enhance the fabrication and application of GNTs as nanofilters.