Macroscopic, Neat, Single-Walled Carbon Nanotube Fibers

Abstract

Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers. Such fibers possess interesting structural composition and physical properties.

Strong Antimicrobial Coatings: Single-Walled Carbon Nanotubes Armored with Biopolymers

“…It is well established that Raman intensity of SWNTs is maximal when exciting light polarization is along the nanotubes axis. [22][23][24] When the air stream was applied in random directions, no change in Raman intensity was observed indicating an isotropic orientation. However, directing the air stream in one direction resulted in a significant degree of alignment and a Raman ratio (G 0 / G 90 ) of 7 ( Figure 3c).…”

The production of soft, durable, and electrically conductive polyester multifilament yarns by dye-printing them with carbon nanotubes

“…The production of continuous yarns of pure CNTs has been accomplished by "dry-spinning", the mechanical process of spinning either the single-walled CNTs directly from a CVD (chemical vapor deposition) gaseous reaction zone [1,2] or with the multi-walled CNTs previously grown as a vertically oriented CNT forest [3,4] . In contrast, "wet-spinning", the spinning of a "super-acid (100 + %sulfuric acid) suspension" [5] of the single-walled CNTs, produced purely CNT-based continuous fibers.The pure CNT-based yarns and/or fibers retained the advantageous properties of the individual nanotubes, such as the high electrical and thermal conductivities. However, the preparation of industrial quantities of the single-walled CNTs or the multi-walled CNT forests, the precursors for making the CNT-based yarns/fibers, is presently impractical.…”

Carbon Nanotubes in Liquid Crystals

“…While uniform alignment under shear is possible, 70 the macroscopic-scale order is lost when the shear stress is removed 62 . If instead the aim is to achieve CNT fibers with a high degree of alignment, the shear-induced director control is however sufficient, as evidenced by the successful solution spinning of carbon nanotube fibers from a nematic phase of 75 SWCNTs suspended in super acid 59 .…”

“…We end this review with a discussion of the case that the LC is not a host for the CNTs, but rather it is formed by the CNTs themselves, a research field that has been developed mainly by the groups around Windle 34,35,38 , Poulin 32,36,49 and Smalley 33,37,59 . The basis for this phenomenon is the classical Onsager argument for liquid crystal phase formation in concentrated suspensions of rigid rods 60,61 : if the aspect ratio of the rods and their concentration are both large enough, the free energy of the system is reduced by forming a nematic 10 phase, the cost of reduced orientational entropy being less than the gain in translational entropy (the latter corresponds to a decrease of excluded volume).…”

“…Each of the three main groups active in the field has chosen its own approach. Whereas Windle and co-workers oxidized their MWCNTs to make them water soluble 34,35,38 , the Smalley team dispersed pristine SWCNTs 55 in super acids 33,37,59 . The Poulin approach was instead to take help of DNA 36 or hyaluronic acid 32 for dispersing SWCNTs.…”