Defect-Free Carbon Nanotube Coils

Abstract

Carbon nanotubes are promising building blocks for various nanoelectronic components. A highly desirable geometry for such applications is a coil. However, coiled nanotube structures reported so far were inherently defective or had no free ends accessible for contacting. Here we demonstrate the spontaneous self-coiling of single-wall carbon nanotubes into defect-free coils of up to more than 70 turns with identical diameter and chirality, and free ends. We characterize the structure, formation mechanism, and electrical properties of these coils by different microscopies, molecular dynamics simulations, Raman spectroscopy, and electrical and magnetic measurements. The coils are highly conductive, as expected for defect-free carbon nanotubes, but adjacent nanotube segments in the coil are more highly coupled than in regular bundles of single-wall carbon nanotubes, owing to their perfect crystal momentum matching, which enables tunneling between the turns. Although this behavior does not yet enable the performance of these nanotube coils as inductive devices, it does point a clear path for their realization. Hence, this study represents a major step toward the production of many different nanotube coil devices, including inductors, electromagnets, transformers, and dynamos.

Fatigue in assemblies of indefatigable carbon nanotubes

“…The indefatigability of nanotubes is only relevant if they are defect-free and ultralong (centimeter to meter range), to be directly tested or used in structural applications, either individually, as in CNT coils ( 32 ), or in the form of macrobundles where each tube spans the entire length, as in ( 3 ). However, practice ( 10 – 12 ) often prevents these realizations, and instead, the tubes are shorter and much thinner than the bundle comprising them, typically with 10 4 to 10 5 of similar hexagonal close-packed CNTs over cross section.…”

Controlling Movement at Nanoscale: Curvature Driven Mechanotaxis

“…A similar methodology was previously used, and it succeeded in reproducing experimental results. [ 43,44 ] The integration of the equations of motion was carried out within the NVE ensemble using the LAMMPS MD package. [ 45 ] The systems were non‐periodic and a time‐step of 1 fs was used in all simulations.…”

Advances in Precise Structure Control and Assembly toward the Carbon Nanotube Industry

“…In fact, it is just the agglomeration of CNTs that links the atomic structure and their mass production. [ 13c ] These structures include agglomerated CNT particles, CNT tangles, [ 10 ] coiled CNTs, [ 43 ] bundled CNTs, [ 9 ] crossed CNTs, [ 11 ] and others. The abundant morphologies have facilitated different application paradigms based on ultralong CNTs, giving rise to functional sensors, optoelectronic devices and high‐strength nanofibers.…”

“…Based on the self‐assembly far from equilibrium, a more orderly coiled morphology can be formed as well. It has been reported that the orderly curled CNTs can be formed via vortex, [ 43b ] ultrasonic irradiation, [ 47 ] or agitation of the reacting gas. [ 48 ] Figure a demonstrates the SWNT rings fabricated by the continuous flow strategy in a high output.…”