Preparation of flexible carbon nanotube ropes for low-voltage heat generator

Carbon nanotube (CNT) ropes (∼1.5 mm in diameter and ∼3000 mm in length) possessing a high degree of flexibility were prepared by twisting CNT socks with the use of rotating motors. Such ropes were not only highly flexible but also dense and homogenous. The structure also allowed the ropes to be easily manipulated without any damage. When the ropes were employed as a heat generator, white incandescence on the rope could be clearly observed even at a low voltage. The properties of the ropes were also validated by observing that water could be boiled after heating for several minutes at a voltage of 15 V. Furthermore, the content of elements in the water before and after heating was unchanged, which demonstrated the structural stability of the ropes. The results indicated the excellent heat transfer performance of the flexible ropes and exhibited potential for use in portable and safe heat generator technology.