"There is currently great interest in the application of single-walled carbon nanotubes as reinforcers in fibres and polymer composites," Valery Khabashesku told nanotechweb.org. "So far, this has been done just by mixing pristine single-walled carbon nanotubes with various polymer matrixes, assuming only a van der Waals nanotube-to-polymer bonding. Attaching the amino-functionality to the sidewalls of the tubes will provide multiple sites for creating covalent bonds to monomers or polymers. This opens up an opportunity for preparing a variety of covalently reinforced nanotube-polymer materials."

The scientists reckon that they attached N-alkylidene amino groups to as many as one in eight sidewall carbon atoms.

"This amino-functionalization approach has been protected by a provisional patent," added Khabashesku. "I am interested in industrial collaboration in order to continue this research at Rice towards the fabrication of new nanoengineered covalently reinforced materials. I hope that companies such as DuPont will become interested."

The functionalized nanotubes could act as building blocks for the preparation of nylon-type cross-linked single-walled carbon nanotube-polymers. Khabashesku says that the tubes can also covalently bind to DNA and drugs and, if made soluble, might serve as nanovehicles for drug delivery.

Now the team plans to scale up the method to allow further incorporation of the functionalized nanotubes into nylon-type processes. They hope to manufacture various co-polymer samples and test their mechanical and thermal properties.

The researchers reported their work in Nano Letters.