Reactivity of Carbon Nanotubes with High Pressures of Nitrogen Dioxide

By Dr. Holly Bevsek, Dept of Chemistry

Nanotechnology is said to be the next step in the industrial revolution. If realized, the ability to produce materials atom-by-atom with specific properties will impact virtually every part of life. At the forefront of nanotechnological research are carbon nanotubes, cylindrical molecules of carbon that have unique structure-dependent electronic and mechanical properties. Consequently, most nanotube studies focus on investigating physical rather than chemical properties. The chemical studies that have been conducted primarily involve efforts to make them water-soluble whereas interactions of carbon nanotubes with gas-phase species have only recently begun to be examined. Furthermore these studies are exclusively performed using low reactant gas pressures; the high pressure regime is unexplored.

Of particular interest is the reaction of carbon nanotubes with nitrogen dioxide (NO₂). NO₂ is a highly reactive atmospheric pollutant and the resistivity of carbon nanotubes is known to be sensitive to its presence. This observation is upheld by theoretical studies, which indicate a strong interaction between NO₂ and the nanotube. However most experiments do not support this as evidence for only weak interactions have been found. The currently held rationale for this conflict is that nanotubes used in experimental studies have structural defects and are of varying and poorly-determined purities. In my seminar I will discuss my research groups investigations over the past year and a half into reactions of purified and “out of the bottle” carbon nanotubes with nitrogen dioxide (NO₂) at increasingly high (up to 1 atm) pressures.