Probing structure and strain transfer in dry-spun carbon nanotube fibers by depth-profiled Raman spectroscopy

The structural properties of dry-spun carbon nanotube (CNT) fibers were characterized by depth-profiled polarized Raman spectroscopy. Results showed that the twisting cannot be fully transferred through the whole fiber and the CNTs within fibers possess non-uniform alignments in radial direction. Effective twisting depth was determined from the residue strain distribution within fibers. Larger surface twisting angles can result in higher residue strain, better alignment degree, and deeper twisting depth. This research suggests a balance should be built between the enhancement of CNT interactions and the increase of defect density to obtain high-performance fibers. (C) 2013 AIP Publishing LLC.