The dispersibility of modified carbon nanotubes in toluene at different temperature has been investigated by laser light scattering. It was found that the nanotubes cannot be dispersed into the level of single tubes. On the other hand, the carbon nanotubes self-assemble in a crystal-like way, with a periodicity around 2 mum. (C) 2003 Elsevier Science B.V. All rights reserved.