A method is provided for exfoliation of carbon nanotubes and for the preparation of a stable aqueous suspension thereof containing dispersed, essentially single tubes, using a water-soluble polymeric material. A powder of carbon nanotubes is further provided, that can be re-dispersed to form a stable suspension. The nanotubes can be used in electronics, printing, coatings, thin layers, molecular machines, and for the production of composite materials.