Polarization behaviors of twisted carbon nanotube fibers

Polarization behaviors of carbon nanotube (CNT) fibers with different twisting were reported. Scanning electron microscope and polarized Raman spectroscopy were used to investigate the prepared samples. Results indicate that surface twisting angle affects greatly the polarization angle and I///I-ratio of twisted CNT fibers. Raman depth profile measurements imply that the twisted fibers consist of non-uniform CNT alignments. A simplified two-CNT-alignment geometric model was proposed to illuminate the experimental observations. The results suggest that polarized Raman depth profile measurement would be a very useful approach for determining the distribution of CNT alignments in CNT fibers.