Matthew Schrandt
NANO 703L Lab 6
Multi-Walled Carbon Nanotubes
In this lab we are analyzing carbon nanotubes using the TEM. Considering carbon nanotubes as similar
to their graphene relatives, we match the diffraction patterns of the nanotubes to their planar
equivalents to help understand the symmetry elements leading to their analysis. Furthermore, the
multiple layers of graphene is likened to multi-walled nanotubes.
Multi-Walled Carbon
Nanotube.
Scale bar reads 10 nm.
TEM magnification = 2Kx.
Outer bore reads 34.98 nm
Inner bore reads 9.85 nm
Number of tubes ≅ 34± 2
The TEM image shown above is of a multi-walled nanotube with approximately 34 rings. The largest of
which is measured to be 34.98 nm. The smallest is 9.85 nm. This inner bore falls is within the expected
dimensions for a single walled nanotube. One single walled nanotube was observed to have a diameter
of 9.00 nm.
Selected area diffraction patterns were also obtained of graphene, SWNT, and MWNT (shown below).
Graphene diffraction pattern
MWNT diffraction pattern
SWNT diffraction pattern
The d spacing for the translational vector d001 (d0001) was calculated using
both the diffraction pattern and also through the measured imaging
pictures of the nanotubes.
From the image of the single walled nanotube (right), the diameter was SWNT image. Scale bar reads 20 nm.
measured to be 9.00 nm. From the diffraction pattern above, the diameter of the first diffraction ring
was measured to be 5.941 nm-1. Using
2
𝑑001
= 5.941 𝑛𝑚−1 , it can be found that d001 = 0.337 nm, which
is close to the expected value of 0.34 nm (for graphene).
For the MWNT, the diameter of the diffraction ring was measured to be 5.711 nm -1. This correlates to
d001 = 0.35 nm. To calculate d001 from the real image, we use the equation 𝑐 =
𝐷2 −𝐷1
.
𝑛
In our case, D2 =
34.98 nm, D1 = 9.85 nm, and n = 34. c = 0.739 nm. c/2 = d001 = 0.37 nm-1. This is close to the number
calculated from the diffraction pattern.
As can be seen from the diffraction patterns, graphene, SWNT, and MWNT are all very similar. The only
noticeable difference in the diffraction patterns is that graphene does not have the averaged crystal
orientations that are shown in the selected areas for the nanotubes. This is likely due to graphene being
less curved (whereas the nanotubes are more string-like) and more locked into a specific angle
(orientation).