**4. Conclusions**

In conclusion, WS2 nanotubes of 1–3 layers ("daughter nanotubes"), 20–100 nm-long and with diameters varying between 3–7 nm, were obtained by plasma treatment of multiwall nanotubes in inert atmosphere. The proposed growth mechanism of the daughter nanotubes involves the strong interaction of the plasma with point or line defects, causing unzipping and exfoliation of the outermost layers of the multiwall nanotube, the release of the elastic strain, followed by scrolling and closure into small nanoscrolls or nanotubes. Sublimation of W and S atoms, WS2 molecules and cluster formation could serve as an additional building material for daughter tube formation and extension. These few-layered WS2 nanotubes represent a locally stable, highly excited state of this solid. Being of such small dimensions, they should reveal a quantum confinement effect, as well as new optical, electrical and mechanical properties. Furthermore, these nanotubes can be suspended in different solvents and could possibly be of particular interest, e.g., for drug delivery.
