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Thermal stability of idealized folded carbyne loops

Steven W Cranford

Author Affiliations

Laboratory of Nanotechnology in Civil Engineering, Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA

Nanoscale Research Letters 2013, 8:490  doi:10.1186/1556-276X-8-490

Published: 20 November 2013

Abstract

Self-unfolding items provide a practical convenience, wherein ring-like frames are contorted into a state of equilibrium and subsequently  pop up’ or deploy when perturbed from a folded structure. Can the same process be exploited at the molecular scale? At the limiting scale is a closed chain of single atoms, used here to investigate the limits of stability of such folded ring structures via full atomistic molecular dynamics. Carbyne is a one-dimensional carbon allotrope composed of sp-hybridized carbon atoms. Here, we explore the stability of idealized carbyne loops as a function of chain length, curvature, and temperature, and delineate an effective phase diagram between folded and unfolded states. We find that while overall curvature is reduced, in addition to torsional and self-adhesive energy barriers, a local increase in curvature results in the largest impedance to unfolding.

Keywords:
Carbyne; Molecular dynamics; Unfolding; Adhesion; Torsion; Curvature; Stability