Higher Recovery and Better Energy Dissipation at Faster Strain Rates in Carbon Nanotube Bundles: An in-Situ Study
Abstract
We report mechanical behavior and strain rate dependence of recoverability and energy dissipation in vertically aligned carbon nanotube (VACNT) bundles subjected to quasi-static uniaxial compression. We observe three distinct regimes in their stress–strain curves for all explored strain rates from 4 × 10^(–2) down to 4 × 10^(–4) /sec: (1) a short initial elastic section followed by (2) a sloped plateau with characteristic wavy features corresponding to buckle formation and (3) densification characterized by rapid stress increase. Load–unload cycles reveal a stiffer response and virtually 100% recoverability at faster strain rates of 0.04/sec, while the response is more compliant at slower rates, characterized by permanent localized buckling and significantly reduced recoverability. We propose that it is the kinetics of attractive adhesive interactions between the individual carbon nanotubes within the VACNT matrix that governs morphology evolution and ensuing recoverability. In addition, we report a 6-fold increase in elastic modulus and gradual decrease in recoverability (down to 50%) when VACNT bundles are unloaded from postdensification stage as compared with predensification. Finally, we demonstrate energy dissipation capability, as revealed by hysteresis in load–unload cycles. These findings, together with high thermal and electrical conductivities, position VACNTs in the "unattained-as-of-to-date-space" in the material property landscape.
Additional Information
© 2012 American Chemical Society. Received for review October 24, 2011 and accepted February 14, 2012. Publication Date (Web): February 14, 2012. The authors acknowledge S. Hutchens for helpful insights and guidance, N. Mohan for data analysis, financial support from the Georgia Institute of Technology Foundation through the Joseph Anderer Faculty Fellowship, and the Institute for Collaborative Biotechnologies (ICB) for financial support through Grant W911NF-09-0001 from the U.S. Army Research Office. The content of the information does not necessarily reflect the position or the policy of the Government, and no official endorsement should be inferred. S.P. gratefully acknowledges support from the W. M. Keck Institute for Space Studies Postdoctoral Fellowship programfor this work. The authors acknowledge critical support and infrastructure provided for this work by the Kavli Nanoscience Institute at Caltech.Attached Files
Supplemental Material - nn300376j_si_001.pdf
Supplemental Material - nn300376j_si_002.pdf
Supplemental Material - nn300376j_si_003.mpg
Supplemental Material - nn300376j_si_004.mpg
Supplemental Material - nn300376j_si_005.mpg
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Additional details
- Eprint ID
- 30243
- DOI
- 10.1021/nn300376j
- Resolver ID
- CaltechAUTHORS:20120420-144857331
- Georgia Institute of Technology Foundation Joseph Anderer Faculty Fellowship
- Army Research Office (ARO)
- W911NF-09-0001
- Keck Institute for Space Studies (KISS)
- Kavli Nanoscience Institute
- Created
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2012-04-23Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Keck Institute for Space Studies, Kavli Nanoscience Institute