Page 117 - Carbon Nanotube Fibres and Yarns

Post-spinning treatments to carbon nanotube fibers 109

(A) (B)
Iron
impurities

10nm 40nm

(C) (D)

Damaged
CNT

40nm 5nm
(E) (F)
100
As-spun fiber As-spun fiber
90 Purified fiber Purified fiber
80 G 2D
70 D
60 50 C
TGA (%) 50 Intensity (a.u.) ID/IG=0.56
40
30
20
10 ID/IG–0.17
0
0 100 200 300 400 500 600 700 800 900 1000 0 1000 2000 3000
–1
Temperature ( C) Wave number (cm )
Fig. 6.2 (A, B) TEM images of as-spun CNT fibers; (C) TEM images of purified CNT fibers;
(D) damaged CNT due to purification, (E) TGA results, and (F) Raman results of the as-
spun and purified CNT fibers.

The intensity ratio (ID/IG) is used to evaluate the defect present on
the CNTs [46]. The increase in the ID/IG ratio of the CNT fibers shown
in Fig. 6.2F from 0.17 to 0.56 after the purification process suggests that
the treatment introduced defects into the CNT structures. The defect in-
crease in the purified CNT structures might stem from the fact that the
CNTs themselves are attacked at their defective sites during the oxidation