Fine needle-like crystals of C60, “C60 nanowhiskers”, were found in 2001 in a colloidal solution of PZT ceramics with added C60. Not only the C60 nanowhiskers but also nanowhiskers composed of C70 and C60 derivatives can be synthesized at room temperature by using the liquid-liquid interfacial precipitation method (LLIP method). Tubular nanowhiskers composed of C60 and C70 molecules have been successfully fabricated by using the LLIP method as well. The tubular fullerene nanowhiskers are named “fullerene nanotubes” here. The tubular fullerene nanowhisker is a new form of single crystalline needle-like crystal whose wall is composed of fullerene molecules. In this paper, structural, electrical and mechanical properties of the fullerene nanowhiskers and fullerene nanotubes are discussed.
C60 nanowhiskers fabricated by the liquid-liquid interfacial precipitation method were sintered at 800 °C under 5.5 GPa for 2 h. Structural, mechanical, and electrical properties of sintered C60 nanowhiskers were compared with those of sintered pristine C60 powder under the same conditions. Sintered C60 nanowhiskers showed a relatively high density and a fine texture as compared to sintered pristine C60 powder probably due to the fibrous morphology of starting C60 nanowhiskers. Analysis using four-probe micro manipulator system (SUNYOU, MMS0024-01) revealed low electrical resistivity for the sintered samples. Electrical resistivity of sintered C60 nanowhisker was slightly higher than that of sintered pristine C60 powder. Both of the sintered samples showed high micro-Vickers hardness about 1100 HV. XRD patterns of the sintered samples showed only diffuse peaks that are characteristic of glassy carbon. The peak intensity of glassy carbon in the sintered C60 nanowhiskers was weaker than that of sintered pristine C60 powder, which was consistent with the different electrical resistivity. Characterization by FTIR and Raman spectroscopy confirmed no sign of C60 molecules for both the sintered samples indicating that C60 molecules were significantly reduced by the high temperature and high pressure treatment. The differences of textural and electrical properties between sintered C60 nanowhiskers and sintered pristine C60 powder suggest a good sinterability of the C60 nanowhiskers due to their fibrous morphology as compared with pristine C60 powder.