Optical microscopy images of CNT/TiO2 strings. Under an optical microscope, TiO2 particles are easily observed. Figure 3b in the text showed that there is an initial stress in the suspended CNT as high as tens of 14 GPa, or a pull of 1´10^-7N, which is much higher than the total gravity force of the several hundred TiO2 particles (1´10-13 N). Therefore, it can be assumed that the suspended CNT is maintained very straight when subjected to the initial stress
Advanced Materials – Superstrong Ultralong Carbon Nanotubes for Mechanical Energy Storage Chinese researchers have synthesized ultralong CNTs with length over 10 cm with perfect structures and no detectable defects. Their CNTs have a breaking strain of up to 17.5%; tensile strength up to 200 GPa; and Young’s modulus up to 1.34 TPa. They could endure a continuously repeated mechanical strain-release test for over 180 million times and remained unbroken.
Superstrong, ultralong, individual carbon nanotubes (CNTs) are deposited with TiO2 particles and visualized under an optical microscope with excellent strain-relaxation reversibility and high fatigue resistance capability. The CNTs with perfect structures have tensile strengths of up to 200 GPa, densities to 1.34 TPa, energy density as high as 1125 Wh kg−1 and the power density can be up to 144 MW kg−1 for mechanical energy storage. The superb mechanical properties confirm the potential of an individual CNT as an effective storage medium with mechanical energy for nano-electromechanical systems, flexible devices, sensors, actuators, antennas, etc.
Energy density-strain curves based on the second Brenner potential method. The ultimate break strain of a CNT is about 18% from theoretical calculation. Chiral, armchair, and zigzag represents three different types of CNTs.