Separation of Single Wall Carbon Nanotubes

[cottonsugar]

Size exclusion chromatography (SEC) has been used to separate single wall carbon nanotubes (SWNT) dispersed by chemical modification in organic solvents and by DNA in aqueous solution. The chromatographic detection includes size sensitive detectors, multi-angle light scattering (MALS) and intrinsic viscosity (IV), which can provide information on the size and shape of the SEC fractions. The dispersions were also characterized by small angle neutron scattering (SANS) and atomic force microscopy (AFM). Chemical modification was accomplished by covalent attachment of octadecyl amine to acid treated SWNT and by covalent attachment of butyl groups through free radical grafting. Both covalent attachment methods produced dispersions that contained impurities or clusters of SWNT. The DNA dispersions produced the best dispersions, being predominately single nanotubes.

※Putus Macromolecular Sci. & Tech. Ltd. is an international corporation which has been putting effort in research, development and application of a variety of carbohydrate polymers. We are manufacturing and providing high quality carbohydrate polymer standards such as GPC/SEC standards, with unique structure and high chemical uniformity in terms of molecular weight (Mw) and degree of branching.

[gatebill]

Hi,
We show that electrostatic charging of nanotubes and the consequent repulsion can lead to reversible separation of individual single-walled carbon nanotubes in bundles. Low-energy electron beam irradiation leads to this completely reversible phenomenon. A simple semianalytical model is used to explain the observed separation mechanism. The reversibility of the separation process is attributed to discharging and thermal-fluctuation induced motion of the nanotubes in ambient air.