How does carbon nanoring deform to spiral induced by carbon nanotube?

Molecular dynamics (MD) simulations have been performed on the interaction between carbon nanoring (CNR) and single-wall carbon nanotube (SWCNT). The results show that, the CNR can spontaneously insert into the hollow interior of the SWCNTs to form a DNA-like double-helix, or collapse to a linked double graphitic nanoribbon and wrap in a helical manner around a tube. Further analyses of energy components show that this unique phenomenon is the result of the Van der Waals interaction. The spiral configuration of the CNR takes the least amount of energy and achieves the maximum occupancy. The sizes of CNR and SWCNT should meet the required conditions to guarantee the spiral form in the insertion and wrapping processes. Two CNRs can also be encapsulated in the SWCNT to form a helix at the same time. Furthermore, we also studied the encapsulation process of CNRs modified with -OH and -H functional groups.