Biomedical Engineering Reference
In-Depth Information
14.2
Some representative functionalization reactions at CNT ends and
defect-sites (Banerjee
et al.
, 2005). SWNTs, single-walled nanotubes.
substitution, to make primary amino groups directly attach onto the carbon
nanotube surface. The carboxylic groups, the majority grafted at the open
ends of CNTs, are replaced with amino groups via Hofmann rearrangement
of carboxylic amide or via Curtius reaction of carboxylic acid chloride with
sodium azide.
One advantage of the defect-site chemistry is that functionalized carbon
nanotubes mostly retain their pristine electronic and mechanical properties
(Zhang et al., 2003). However, as mentioned earlier, the spatial distribution
of grafted functions is not homogeneous. In fact, the majority of carboxylic
groups, used as anchoring sites, are localized at the extremities of the carbon
nanotubes.
