Paper GR-TuP6
Fabrication, Structural Characterization, and Surface Modification of Carbon Nanoballs

Tuesday, October 21, 2008, 6:30 pm, Room Hall D

Carbon related materials, eg, C60, CNT, diamond, and DLC, have attracted much attention and can be widely used in practical engineering fields. Synthesis of the carbon materials by chemical vapor deposition (CVD) have been considered as one of synthesis methods toward mass production. Carbon nanoballs (CNBs) can be also synthesized by the techniques that are normally used to produce carbon nanotube (CNT). CNBs have been expected to apply polymer composites and biological systems. In the case of application to the polymer composites, it is necessary to tailor the chemical property of the CNBs surface in order to covalently bind the polymer to the CNBs. In order to fabricate the CNBs-polymer composite, it is crucial to establish the surface modification method of the CNBs. In this study, we aimed to fabricate the CNBs by thermal CVD and to chemically introduce carboxylic acid groups to the CNBs surface. Fe-sputtered silicon wafer was used as a substrate. A target of Fe (99.99%) was used as received. A quartz tube in a ringed furnace was used as thermal CVD reactor. The substrate was placed on the center of the quartz tube. Reaction temperatures were changed from 750 to 990^oC. The source gases were H₂ (100 sccm) and CH₂=CH₂ (25,75, 100, and 175 sccm). The samples obtained were characterized by FE-SEM, TEM, and Raman spectroscopy. The introduction of carboxyl groups to CNBs’ surface were carried out by chemical wet process and vacuum ultra-violet (VUV) irradiation. The CNBs were successfully fabricated at the temperature of 850 and 990 ^oC. Raman spectra showed that the CNBs had two peaks at around 1350 and 1590 cm^-1, which correspond to D and G bands, respectively. The carboxyl groups were introduced to the CNBs surface by chemical wet process. The COOH-terminated CNBs were uniformly dispersed in water, ethanol, and acetone.