Abstract Submitted to the NANOTUBE'02 Workshop:

In this paper, we described the fabrication and characterization of aligned and very long multi-walled carbon nanotubes (MWNTs) made by chemical vapor deposition (CVD) of hydrocarbon gas, for example acetylene, on porous substrates. Aligned MWNTs array with high density and purity were achieved by CVD on both bulk silica substrate and the film-like substrates, and has the uniform diameter of 10-20nm and the spacing among the tubes is about 100nm. We have directly measured the Young’s modulus and tensile strength of MWNTs arrays by pulling very long (~2mm) aligned carbon nanotubes ropes with a specially designed stress-strain puller. The average Young’s modulus and tensile strength obtained were 0.45Tpa and 1.72Gpa respectively. By scanning probe microscope with an indentation/scratch function the radial compression of an individual MWNT under an asymmetric stress was investigated the specific heat and the thermal conductivity of MWNTs arrays in the range from room temperature up to 20mk were measured. We found that the specific heat of MWNTs follows a strikingly linear temperature dependence over the entire temperature range measured (10-300K), and the thermal conductivity takes a quadratic T-dependence below ~120 K and turns to be linear above that temperature.