Debundling of single-walled carbon nanotubes by using natural polyelectrolytes

Abstract

Natural polyelectrolytes (NPs), including sodium lignosulfonate, humic acid and so forth, are reported for the first time to solubilize single-walled carbon nanotubes (SWNTs) in water through a noncovalent interaction. A variety of methods, including transmission electron microscopy (TEM), visible–near-infrared (vis–NIR) spectra, Raman spectra and zeta potential measurements, were used to characterize the NP-dispersed SWNT solutions. It is found that the SWNTs can be exfoliated into thin bundles or individual tubes, even at NP concentrations as low as 0.15 mg ml−1. Their high performance is attributed to the abundance of aromatic groups and ionized groups in the NP molecules. This method of solubilization opens the way for exploiting new natural materials as SWNT solubilizers and may find applications in nanocomposites, self-assembly, and so forth.

The effect of carbon nanotube aspect ratio and loading on the elastic modulus of electrospun poly(vinyl alcohol)-carbon nanotube hybrid fibers

“…In order to disperse CNTs in PVA solution for electrospinning hybrid fibers, the LSA content was intentionally increased from what Liu et al [28] proposed (1.5 mg LSA per 1 mg CNTs) to 2 mg LSA per 1 mg CNTs in the solution to induce a significant plasticizing effect [33,34]. The elastic moduli of PVA fibers exhibited a significant size-dependence, increasing from 8 to 17 GPa as the diameter decreases from 250 to 150 nm.…”

“…This paper advocates the use of lignosulfonic acid sodium salt (LSA) to effectively disperse [28] pristine CNTs in water towards the fabrication of hybrid fibers based on poly(vinyl alcohol) (PVA). PVA has good thermal stability, chemical resistance and biocompatibility [29].…”

Preparation of semiconductor-enriched single-walled carbon nanotube dispersion using a neutral pH water soluble chitosan derivative

“…The nanotubes dispersed in biocompatible media are of special interest for applications such as biosensor, template for cell culture, SWNT-biomacromolecule hybrid, etc. Various biomolecules, biosurfactants and biopolymers including DNA, proteins, poly(L-lysine), starch, gelatin, steroids and chitosan have shown capability for the effective debundling and individual dispersion of SWNTs in water [26][27][28][29][30].…”

In-Situ Structural Characterization of Single-Walled Carbon Nanotubes in Dispersion

“…To disperse SWCNTs in a given medium at the molecular level or to exfoliate the SWCNT bundles into individual tubes, the strong intertube cohesive energy has to be overcome. This proved to be a difficult task (O'Connell et al, 2002;Islam et al, 2003;Moore et al, 2003;Zheng et al, 2003;Cotiuga et al, 2006;Giordani et al, 2006;Bergin et al, 2007;Liu et al, 2007;Liu et al, 2009). Lastly, the difficulty to disperse SWCNTs is also attributed to the topological entanglement or enmeshment of long aspect ratio SWCNTs, which could result kinetically quenched fractal structures or aggregates.…”