Comparative Dispersion Studies of Single-Walled Carbon Nanotubes in Aqueous Solution

Abstract

Single-walled carbon nanotubes (SWCNT) produced by various methods are commercially available but systematic characterization of their dispersion behavior in aqueous solution is rare. Here, we compare the properties of various SWCNT after their dispersion in aqueous solution assisted by DNA oligo. UV-vis-NIR absorbance measurement and atomic force microscopy (AFM) imaging showed marked differences among SWCNT produced from arc-discharge (AD) method, chemical vapor deposition (CVD), and high-pressure carbon monoxide process (HiPCO). To our surprise, the SWCNT produced from AD method showed the highest nanotube purity and the cleanest AFM image, better than HiPCO SWCNT that has been used extensively for biological applications. We also report our systematic studies on optimizing dispersing conditions to maximize SWCNT solubility and remove insoluble materials. We recommend a low power and short time of sonication to disperse SWCNT to preserve their average lengths. These results altogether serve as a future guide for the usage of commercial SWCNT in water-based applications.

Optimizing sonication parameters for dispersion of single-walled carbon nanotubes

“…4, A and B show the three-dimensional (3-D) mappings of the A R and the A R /A NR ratio as a function of the sonication power and the time duration, respectively. The resonant optical absorption depends on the concentration and the average length of isolated SWCNTs, and thus can be used to characterize the degree of debundling of the SWCNTs in the solution [25,29,33]. The initial concentration of SWCNTs was the same, therefore the changes are due to the various sonication parameters.…”

“…The dispersion mechanism has been explored and results indicate that the adsorption of surfactants on the surface of SWCNTs forms stronger p-p stacking interactions than those between the SWCNTs [21]. For the non-covalent functionalization of SWCNTs, the useful agents include surfactants, polymers, as well as biomolecules such as DNA [5,[22][23][24][25]. The most common surfactants can be divided into three types on the basis of their polarization: anionic, cationic and non-ionic surfactants.…”

“…This is due to the fact that the p-p stacking interaction between phenyl rings and the surface of SWCNTs is much stronger than that of other groups. So far, lots of effort has been focused on the study of the properties of surfactants with a 0301-0104/$ -see front matter Ó 2012 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.chemphys.2012.08.020 variety of concentrations [11,14,25]. Moreover, molecular dynamic simulations have also been applied to investigate the basic interactions between the SWCNTs, surfactant and water molecules [13].…”

Non-covalent conjugates of single-walled carbon nanotubes and folic acid for interaction with cells over-expressing folate receptors

“…11,[19][20][21][22] In particular, vibrational spectra can provide useful insights into aggregation, dispersion and functionalization states of SWCNTs.…”

Calentamiento por Fotoactivación de NanoTubos de Carbono de pared simple Funcionalizados con Ácido Fólico (NTC-AF)

“…El espectro Raman del NTC permite ver la modificación de los modos vibracionales por efecto de la funcionalización del NTC (Koh B., et al, 2011). Se identifica que la zona comprendida entre 200 y 300 cm -1 se presenta los modos de respiración radial conocidos como RBM (Radial Modes Breathing, siglas en ingles), los cuales presentan una relación inversa con el diámetro del nanotubo y son útiles para evidenciar la funcionalización de los NTC.…”