Carbon nanotubes (NTs) are often synthesized as ropes or bundles of highly aligned tubes, but many applications require individual NTs. Separation methods that coat the NTs with organic solvents or polymers can alter the electronic properties of the NTs, and sonication with a surfactant can cut and damage the NTs.
Drawing on an ancient Egyptian recipe for making carbon-black ink, Bandyopadhyaya et al. used gum arabic (GA), a highly branched arabinogalactan polysaccharide, to dissolve individual NTs in aqueous solution. The authors argue that gum arabic physically adsorbs onto the NT surfaces and causes the NTs to exfoliate. Once in solution, the adsorbed polymer chains repel each other, thus disrupting the interactions between tubes and stabilizing the isolated NTs. -- MSL
Nano Lett., 10.1021/nl010065f.