Limits...
Thermal stability of idealized folded carbyne loops.

Cranford SW - Nanoscale Res Lett (2013)

Bottom Line: 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Nanotechnology in Civil Engineering, Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA. s.cranford@neu.edu.

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.

No MeSH data available.


Simulation snapshots and root mean square displacement (or rmsd; see Equation 1) trajectories. Structures for n = 144 during low- and high-temperature simulations. For low temperature (300 K, bottom), the folded three-loop structure remains stable and is an equilibrated state (indicated by the relatively constant RMSD). Increasing the temperature (750 K, top) induces unfolding, after which the unfolded structure equilibrates (larger variation in RMSD due to the oscillations induced by the momentum of unfolding).
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Figure 3: Simulation snapshots and root mean square displacement (or rmsd; see Equation 1) trajectories. Structures for n = 144 during low- and high-temperature simulations. For low temperature (300 K, bottom), the folded three-loop structure remains stable and is an equilibrated state (indicated by the relatively constant RMSD). Increasing the temperature (750 K, top) induces unfolding, after which the unfolded structure equilibrates (larger variation in RMSD due to the oscillations induced by the momentum of unfolding).

Mentions: Example snapshots of an unfolding loop are given in Figure 3, along with the associated root mean square deviation (RMSD) plot. The RMSD is defined as the spatial difference between two molecular structures:


Thermal stability of idealized folded carbyne loops.

Cranford SW - Nanoscale Res Lett (2013)

Simulation snapshots and root mean square displacement (or rmsd; see Equation 1) trajectories. Structures for n = 144 during low- and high-temperature simulations. For low temperature (300 K, bottom), the folded three-loop structure remains stable and is an equilibrated state (indicated by the relatively constant RMSD). Increasing the temperature (750 K, top) induces unfolding, after which the unfolded structure equilibrates (larger variation in RMSD due to the oscillations induced by the momentum of unfolding).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3842786&req=5

Figure 3: Simulation snapshots and root mean square displacement (or rmsd; see Equation 1) trajectories. Structures for n = 144 during low- and high-temperature simulations. For low temperature (300 K, bottom), the folded three-loop structure remains stable and is an equilibrated state (indicated by the relatively constant RMSD). Increasing the temperature (750 K, top) induces unfolding, after which the unfolded structure equilibrates (larger variation in RMSD due to the oscillations induced by the momentum of unfolding).
Mentions: Example snapshots of an unfolding loop are given in Figure 3, along with the associated root mean square deviation (RMSD) plot. The RMSD is defined as the spatial difference between two molecular structures:

Bottom Line: 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Nanotechnology in Civil Engineering, Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA. s.cranford@neu.edu.

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.

No MeSH data available.