Electrical Resistivity of Pristine and Functional Single-Wall Carbon Nanotubes

Yijiang Lu,Jing Li,Haiping Hong

doi:10.1155/2013/635673

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.

Highlights

Carbon nanotubes have attracted extensive attention recently because of their extraordinary thermal, electrical, and mechanical properties [1,2,3]
With an applied electric field, no change was observed in resistance for purified pristine single-wall carbon nanotubes (SWNTs), COOH-SWNTs, and fluorinated SWNTs
A significant decrease in resistance was observed from sulfonated SWNTs and unpurified pristine SWNTs when an electric field was applied, indicating that they both align within an electric field

Summary

Introduction

Carbon nanotubes have attracted extensive attention recently because of their extraordinary thermal, electrical, and mechanical properties [1,2,3]. Due to these unique properties, they have the potential to be used in electrical devices [4], nanofluids [5, 6], grease [7], and sensors [8,9,10]. It is interesting to investigate the effect of the added functional groups on electrical resistance to better understand how the chemical bonds and geometric/electronic configuration affect the electrical properties of the SWNTs. In this paper, the electrical resistance of several pristine and functionalized SWNTs was investigated with and without an electric field to better understand the relationship between nanotube structure and physical properties (thermal, electrical, and mechanical)

Experimental and Procedure

Results and Discussion

Purified pristine SWNT

Conclusions