Controlling the phase behavior of single-walled carbon nanotube: Superacid dispersions

PRES 36

Virginia A. Davis1, Valentin Prieto2, Pradeep Rai2, A. Nicholas G. Parra-Vasquez, alario33@rice.edu2, Robert A. Pinnick2, Robert Hauge, Hauge@rice.edu3, Richard E. Smalley4, and Matteo Pasquali, mp@rice.edu5. (1) Department of Chemical Engineering, Auburn University, 0335 Haley Center, Auburn, AL 36849, (2) Department of Chemical Engineering, Rice University, 6100 Main St. MS-362, Houston, TX 77005, (3) Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main Street, MS100, Houston, TX 77005, (4) Department of Chemistry, Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main Street, MS 100, Houston, TX 77005, (5) Chemical and Biomolecular Engineering Department, Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main St. MS-362, Houston, TX 77005
We report the first known characterization of the impact of solvent quality on SWNT-liquid crystal morphology and phase boundaries. For SWNTs dispersed in superacids, altering the protonating ability of the solvent has a direct impact on the isotropic-nematic phase boundary of SWNT-superacid dispersions. In addition, the liquid crystal morphology and the microstructure of solid fibers solution spun from the dispersion can be altered by increasing the protonating ability of the solvent. In contrast, the biphasic - nematic transition is relatively insensitive to the solvent quality, and is dictated by the distribution of aspect ratios.