Nanoresistors and Single-Walled Carbon Nanotubes: Using An Ohmmeter to Test for Hybridization Shifts

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 10 Issue 4 (2005) pp 260-264

Nanoresistors and Single-Walled Carbon Nanotubes: Using An Ohmmeter to Test for Hybridization Shifts

Katie Olsen,^† Lori Hardin,^† Justin McGovern,^† Thomas J. Manning^†,*, Dennis Phillips,^‡ Tim Ayers,^§ and Michael A. Duncan^§

^†Department of Chemistry, Valdosta State University,Valdosta, Georgia 31698, tmanning@valdosta.edu; ^‡Mass Spectrometry Laboratory, Department of Chemistry, University of Georgia, Athens, Georgia; ^§Chemistry Department, University of Georgia, Athens, Georgia
Received January 5, 2005. Accepted March 1, 2005.

Published online: 23 June 2005

Abstract. Single-walled carbon nanotubes (SWNTs) can conduct electricity under ambient conditions. In a hands-on activity, students react Br₂ and I₂ with SWNTs and demonstrate that the dopants lower the resistance of SWNTs. In two other activities they demonstrate that Cl₂ (generated by reacting Clorox and hydrochloric acid) and NaOH, when reacted with the tubular carbon structures, increase the resistance of SWNTs. This is due to the conversion of sp²-hybridized carbon atoms to functionalized carbon atoms (C–OH, C–Cl) that assume sp³ hybridization, thus causing the SWNT to lose their conductivity. In an appendix, a simple demonstration involving ten forms of carbon allotropes reacting with nitric acid (or not reacting!) is discussed.

Key Words: Laboratories and Demonstrations; general chemistry; organic chemistry; nanotechnology

(*) Corresponding author. (E-mail: tmanning@valdosta.edu)

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