Single-walled carbon nanotube growth with non-iron-group “catalysts” by chemical vapor deposition

Various materials have been found to “catalyze” carbon nanotube growth in chemical vapor deposition (CVD) when they become nano-sized particles. These involve not only metals, such as Pd, Pt, Au, Ag, and Cu, but also semiconductors, such as Si, Ge, and SiC. Alumina and diamond nanoparticles also produce carbon nanotubes. These “catalysts”, which are better called “seeds”, can be categorized into two types: one type forms a eutectic liquid or highly-mobile alloy with carbon, and carbon atoms precipitate from the eutectic alloy; the other type remains as a solid phase and form a carbon surface layer during CVD growth. In this paper, we review recent studies of SWCNT growth with these non-iron-group materials and highlight the mechanisms involved.      

Structural Change of Potato Starch Granules by Ball-mill Treatment

Molecular change of potato starch granule by ball-mill treatment was investigated. Starch granule still retained its whole figure after 320h, treatment, but its surface changed extremely rough. Water absorption activity extremely increased by 10h treatment. Amylase susceptivity of starch increased according to treatment time. X-ray diffraction pattern lost its peak and enthalpy on DSC decreased 70% after 20h treatment. Iodine color reaction value decreased 30% and λ max shifted hypso-chromic 15nm in the both cases of debranched and non-debranched samples after 20h treatment, and this indicates amylose was also degraded by the treatment. However, the peak of amylose decreased 10% and the peak of amylopectin decreased 10% on each GPC of branched and non-debranched samples after 20h treatment. GPC (Toyopearl HW-65) of 320h treated sample shows only one peak, but its debranched sample shows similar pattern to that of non-treated sample on HPAEC. ¹³C-solid state NMR spectra suggest that total disruption frequency is fairly low after long this treatment.