Tying carbon nanotubes using the double helix structure of a trefoil knot

Abstract

The entanglement between heterogeneous materials at the nanometer scale is an interesting phenomenon by which the structure and properties of materials become significantly correlated. Herein, a computational framework is introduced for systematically analyzing the mechanical behavior of trefoil knots at the atomic scale. The changes in the mechanical stress and structural deformation characteristics of carbon nanotube (CNT) bundles of different diameters are evaluated with respect to the tightening and releasing a knotted molecular lasso. In the process of equilibrating the tightened CNT bundles, the helical reorientation of dangling hydrogen atoms in the trefoil knot is a crucial factor in preventing the lasso knot from unfurling. In particular, the correlation between the characteristic curvature formed when polymer chains bind nanotube bundles, and the persistence of the knot structure is quantitatively elucidated. These findings can serve as a bottom-up design method to determine the fundamental aspects behind the mechanical properties of nanostructures and nanocomposites.