Double-walled carbon nanotube dispersion via surfactant substitution

Abstract

A new approach for the stabilisation of double-walled carbon nanotubes in aqueous media was developed. A low molecular weight surfactant was used in the first stage for the debundling of the nanotubes followed by substitution with a higher molecular weight surfactant or non-ionic surfactants. Dispersions were characterized by optical density measurements, SEM and DLS. The presence of remaining low molecular weight surfactant was investigated by FT-IR. Double walled carbon nanotube dispersions showed good dispersion stability and non-detectable amounts of the initial surfactant, which was completely removed. Such a method could be useful for preparation of stable aqueous dispersions of carbon nanotubes with low concentration of surfactants, which is especially important for toxicity studies.

Chronic Toxicity of Double-Walled Carbon Nanotubes to Three Marine Organisms: Influence of Different Dispersion Methods

“…The influence of the addition of a surfactant was not discussed here, as it was not desirable to interfere with the intrinsic toxicity of the surfactant itself. However, the presence of surfactants (either natural [33] or man-made [34]) cannot be ruled out and should play an important role in terms of separation of the CNTs (e.g., debundling and dispersion of aggregates) and stabilization of the obtained suspensions, even at a very low concentration [34].…”

Quantitative evaluation of multi-walled carbon nanotube uptake in wheat and rapeseed

“…Due to their amphiphilic properties NOM (humic and fulvic acids) have been shown to enhance the stability of CNTs in the environment [11][12][13][14]. Other amphiphilic molecules would have the same properties, particularly gum Arabic (GA), a polysaccharide which is classically used for CNT dispersion in aqueous solutions [15].…”

Nanoparticle-Liquid Crystalline Elastomer Composites

“…In the design of a useful dispersant for the introduction of CNTs into an LCE matrix, polymeric dispersants are preferred to small molecules. Small molecule dispersants usually act to separate CNTs using electrostatic forces or micelle formation, while non-ionic polymeric dispersants are capable of following the -wrapping‖ mechanism [68,69], thus preventing de-bundled CNTs from re-aggregating even after solvent evaporation. By designing the dispersant polymer to be compatible with the liquid crystalline matrix, the LC order in the material can be preserved.…”