Morphology control of a rapidly grown vertically aligned carbon-nanotube forest for fiber spinning

Carbon nanotube (CNT) fibers have interesting applications because of their good electrical and mechanical properties. CNT fiber is fabricated in a simple way, that it is spun from a vertically aligned CNT forest (VACNF). Spinning occurs by joining of CNT when the CNT at the edge of a VACNF is drawn horizontally. However, the mechanism of spinning is still not clear. To investigate it, we fabricated a spinnable VACNF by thermal chemical vapor deposition (CVD) and compared it with unspinnable VACNF by scanning electron microscope (SEM) observation and polarized Raman spectroscopy. It was found that there were a few big differences between spinnable and unspinnable VACNFs. In the case of spinnable VACNF, most of the CNTs are straight and well aligned. Spinnable VACNF also contains CNT bundles consisting of 8-10 CNTs that are not vertically aligned. This CNT bundle was shared by a few adjacent thicker CNT bundles. These points are very important for continuous fiber spinning.