Instabilities in carbon nanocone stacks

A Raj and A Mokhalingam and SS Gupta, CARBON, 127, 404-411 (2018).

DOI: 10.1016/j.carbon.2017.11.023

Possessing remarkable electronic, mechanical and optical properties, pristine single-walled carbon nanocones (CNCs) are envisioned here to be pulled-out co-axially from a nanocone stack. The process is simulated using molecular mechanics (MM) and dynamics (MD) employing MM3 and REBO + LJ potentials, respectively. During pulling-out, rim of the lowermost cone is constrained while the tip of the outermost cone is displaced axially from its equilibrium, quasi-statically in case of MM and by prescribing velocity of 0.1 angstrom/pico-sec in case of MD. During pulling-out, at a critical distance, the top cone abruptly breaks the axial symmetry with its wall deforming considerably outward. The source of this instability is building-up of compressive circumferential strain in the wall with increasing displacement; a competition between stretching and van der Waal's energy terms of the system. Interestingly, during reversal of the pulling-out process, the system is found to trace a different equilibrium path. Further, in a few-walled CNCs if the tip of the top-most cone is compressed from its equilibrium position, the stack inverts completely by breaking axial symmetry aided by snap- through buckling in segments of the periphery. Irrespective of apex angle, hydrogen passivation, temperature and potential used, the aforementioned observations are found to be intrinsic to the system. (C) 2017 Elsevier Ltd. All rights reserved.

Return to Publications page