US Patent 7419650 - Functionalized Short CNTs

http://www.freepatentsonline.com/7419650.html

For applications in hydrogen storage and as molecular sieves short length (<1 micron) carbon nanotubes have been found to have advantages over longer tube lengths for the diffusion of gases. This patent discloses a method for producing such short length CNTs. Claim 1 reads:

1. A method for producing functionalised short carbon nanotubes with at least one open tip comprising mechanically treating long carbon nanotubes in a powder form, wherein a reactant gas able to chemically react with said long nanotubes is chosen and said long carbon nanotubes in a powder form are submitted to mechanical milling forces in the presence of said reactant gas so that short carbon nanotubes, comprising at least one specific chemical group, are obtained, and wherein said reactant gas is not air.