Exponential decrease of scission length and low tensile strength of bamboo-shaped multi-walled carbon nanotubes under ultrasonication

We report here scission of bamboo-shaped multi-walled carbon nanotubes (BS-MWCNTs) under ultrasonication. As the applied sonication energy increases, mean length of BS-MWCNTs decreases. When sonication energy increases over 500 J/mL, the length of BS-MWCNTs no longer decreases; the limited scission length (L₀) is about 1.7 μm for BS-MWCNTs with diameter between 50 and 100 nm. From the L₀ of BS-MWCNTs, their tensile strength (σ^∗) is calculated and found to be smaller than that of multi-walled carbon nanotubes (MWCNTs). In addition, exponential decrease of the length of BS-MWCNTs with increasing sonication energy is observed, which is distinguished from typical power law dependence of sonication-induced scission of MWCNTs. These exclusive characteristics in the scission of BS-MWCNTs under ultrasonication are regarded to result from weak binding at discontinuous graphene sheets obtained from forming compartment structures of BS-MWCNTs during growth.