Synthesis and Characterization of Vertically Aligned Carbon Nanotube Forest for Solid State Fiber Spinning

Abstract

Continuous carbon nanotubes (CNT) fibers were directly spun from a vertically aligned CNT forest grown by a plasma-enhanced chemical vapor deposition (PECVD) process. The correlation of the CNT structure with Fe catalyst coarsening, reaction time, and the CNTs bundling phenomenon was investigated. We controlled the diameters and walls of the CNTs and minimized the amorphous carbon deposition on the CNTs for favorable bundling and spinning of the CNT fibers. The CNT fibers were fabricated with an as-grown vertically aligned CNT forest by a PECVD process using nanocatalyst an Al2O3 buffer layer, followed by a dry spinning process. Well-aligned CNT fibers were successfully manufactured using a dry spinning process and a surface tension-based densification process by ethanol. The mechanical properties were characterized for the CNT fibers spun from different lengths of a vertically aligned CNT forest. Highly oriented CNT fibers from the dry spinning process were characterized with high strength, high modulus, and high electrical as well as thermal conductivities for possible application as ultralight, highly strong structural materials. Examples of structural materials include space elevator cables, artificial muscle, and armor material, while multifunctional materials include E-textile, touch panels, biosensors, and super capacitors.

Unconventional Thermoelectric Materials for Energy Harvesting and Sensing Applications

“…230 Vertically aligned CNT arrays can also be dryspun into fibers. 289 Mild liquid-phase processing can be achieved by producing slurries in solvents (with no surfactants and no sonication) or by producing true solutions in strong acids such as chlorosulfonic acid. 247,275 The latter technique can be paired with a coagulation-bath-assisted spinning process to produce highly aligned CNT fibers with exceptional alignment, strength, and conductivity (Figure 31b).…”

“…Yarns and fibers can be directly spun from as-produced CNT “webs” or “socks”, often straight from the reactor in a continuous process and typically via pulling through a liquid densification bath and rolling onto a roller (Figure a) . Vertically aligned CNT arrays can also be dry-spun into fibers . Mild liquid-phase processing can be achieved by producing slurries in solvents (with no surfactants and no sonication) or by producing true solutions in strong acids such as chlorosulfonic acid. , The latter technique can be paired with a coagulation-bath-assisted spinning process to produce highly aligned CNT fibers with exceptional alignment, strength, and conductivity (Figure b) .…”