Sec.3.1, CNCs (coiled shape; diameter ~ 100e200 nm) can be easily
distinguished from CNTs (straight; diameter ~ 20e30 nm) and CNFs
(straight; diameter >100 nm) by the shape and diameter.
Fig. 6 shows that the growth rate of CNCs increased from
approximately 1 mg/h (25 sccm C2H2) to approximately 3.5 mg/h
(50 sccm C2H2), and then to approximately 4.5 mg/h (100 sccm
C2H2). The growth rate exhibited a larger increment when the C2H2
flow rate increased from 25 to 50 sccm. The reason for the larger
increment of the growth rate between the 25 and the 50 sccm C2H2