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Journal of Nanomaterials
Volume 2013 (2013), Article ID 635673, 5 pages
http://dx.doi.org/10.1155/2013/635673
Research Article

Electrical Resistivity of Pristine and Functional Single-Wall Carbon Nanotubes

1Nanotechnology Branch, NASA Ames Research Center, Moffett Field, Sunnyvale, CA 94035, USA
2Department of Material and Metallurgical, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA

Received 6 January 2013; Accepted 16 February 2013

Academic Editor: Yun Zhao

Copyright © 2013 Yijiang Lu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The resistance of several pristine and functional single-wall carbon nanotubes (SWNTs) deposited and dried on interdigitated electrode (IDE) chips was investigated to better understand how functional groups influence their resistivity. Without the external electrical field, the resistance was generally increased for the sulfonated and fluorinated SWNTs but not for COOH-SWNTs. With a 3 V electric field applied during depositing, while no change in resistance was found for the purified pristine SWNTs, fluorinated SWNTs, COOH SWNTs, and Ni-SWNTs, a significant decrease in resistance was observed in sulfonated SWNTs and unpurified pristine SWNTs, which could be due to the alignment of SWNTs in an electric field. The alignment of the sulfonated SWNTs is most likely due to the charge of the sulfate functional group. It is interesting to note that the alignment was found in the unpurified pristine SWNTs but not in the purified pristine ones which have lessened resistivity. The lower resistivity in the purified pristine SWNTs may be due to the smaller number (<5%) of impurities. The significance of this research is that hydrophilic COOH-SWNTs could be a better candidate than the hydrophobic pristine SWNTs for being used in many applications, especially in polymer nanocomposites.