Individually Dispersing Single-Walled Carbon Nanotubes in Water without Cutting

Abstract

Single-walled carbon nanotubes (SWCNTs) are one of the most intensively studied nanomaterials due to their extraordinary mechanical, electrical and optical properties. Many fundamental studies and applications of SWCNTs, such as imaging, sensing and sorting, require SWCNTs to be dispersed in aqueous solutions first1, which is typically realized via ultrasonication in the presence of surfactants followed by ultracentrifugation2. However, due to the large energy input, ultrasonication inevitably introduces defects to SWCNTs and cuts the tubes into smaller pieces, compromising the many intriguing properties of SWCNTs3,4. Here, we show a simple method that disperses individual SWCNTs in water while retaining their lengths and avoiding introduction of defects. The as-prepared SWCNTs are 350% longer in length and 150% lower in defect density than their sonicated counterparts. These SWCNTs can also be further sorted in a chirality-specific manner. Due to the nondestructive merit of our method, the resulting full-length tubes showed a 50% increase in photoluminescence and an order of magnitude improvement in sheet conductance over those of sonicated controls. 1De Volder, M. F. L., Tawfick, S. H., Baughman, R. H. & Hart, A. J. Science 339, 535–539 (2013). 2Pagani, G., Green, M. J., Poulin, P., & Pasquali, M. Proc. Natl. Acad. Sci. 109, 11599–11604 (2012) 3Hecht, D.S., Hu, L. & Irvin, G. Advanced Materials 23, 1482-1513 (2011). 4Tabakman, S.M., Welsher, K., Hong, G. & Dai, H. The Journal of Physical Chemistry C 114, 19569-19575 (2010).