Preparation of highly pure and crystalline carbon nanotubes and their infiltration by paraffin wax

Carbon nanotubes (CNTs) of ultrahigh purity and high crystallinity, which could be used for the encapsulation of nanoscaled materials, were fabricated by the heat treatment of disordered CNT-encapsulated In–Sn nanowires at temperatures lower than 1800°C in H2 under vacuum conditions (pressure of approximately 1Pa). The results showed that nearly 100% of the encapsulated In–Sn alloy was removed at 1800°C, and as much as 99.99% of it at 1600°C. The prepared CNTs were also filled with paraffin wax. A vacuum-based infiltration–purification process proved effective for fabricating the CNT–paraffin hybrid structures at a high filling yield, which was confirmed by thermograms and TEM observations.