Thermal expansion of single-walled carbon nanotube (SWNT) bundles: X-ray diffraction studies - art.no. 241402

Thermal expansion coefficient in single-walled carbon nanotube bundles was determined: as (-0.15 +/- 0.20) x 10(-5) (1/K) for the tube diameter and (0.75 +/- 0.25) x 10(-5) (1/K) for the triangular lattice constant by means of x-ray scattering between 300 K to 950 K. The value for the intertube gap was (4.2 +/- 1.4) x 10(-5) (1/K), which is larger than 2.6 x 10(-5) (1/K) for the c-axis thermal expansion in graphite. The results reveal the presence of a remarkably larger lattice anharmonicity in nanotube bundles than that of graphite. The small value for the tube diameter is consistent with the seamless tube structure formed by a strong covalent bond between carbon atoms comparable to that in graphite.