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Published September 2011 | public
Journal Article

Tailoring the microstructure and mechanical properties of arrays of aligned multiwall carbon nanotubes by utilizing different hydrogen concentrations during synthesis


We synthesize vertically aligned arrays of carbon nanotubes (CNTs) in a chemical vapor deposition system with floating catalyst, using different concentrations of hydrogen in the gas feedstock. We report the effect of different hydrogen concentrations on the microstructure and mechanical properties of the resulting material. We show that a lower hydrogen concentration during synthesis results in the growth of stiffer CNT arrays with higher average bulk density. A lower hydrogen concentration also leads to the synthesis of CNT arrays that can reach higher peak stress at maximum compressive strain, and dissipate a larger amount of energy during compression. The individual CNTs in the arrays synthesized with a lower hydrogen concentration have, on average, larger outer diameters (associated with the growth of CNTs with a larger number of walls), but present a less uniform diameter distribution. The overall heights of the arrays and their strain recovery after compression have been found to be independent of the hydrogen concentration during growth.

Additional Information

© 2011 Elsevier Ltd. Received 7 January 2011; accepted 28 April 2011. Available online 5 May 2011. The authors thank Prof. Julia R. Greer and Prof. A. John Hart for conversations leading to this work. This work is supported by the Institute for Collaborative Biotechnologies, under contract W911NF-09-D-0001 with the Army Research Office. JRR also gratefully acknowledges support from the Department of Defense via a National Defense Science & Engineering Graduate (NDSEG) fellowship.

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