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Nonlinear viscoelasticity of freestanding and polymer-anchored vertically aligned carbon nanotube foams

Lattanzi, Ludovica and Raney, Jordan R and De Nardo, Luigi and Misra, Abha and Daraio, Chiara (2012) Nonlinear viscoelasticity of freestanding and polymer-anchored vertically aligned carbon nanotube foams. In: Journal of Applied Physics, 111 (7).

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Official URL: http://dx.doi.org/10.1063/1.3699184


Vertical arrays of carbon nanotubes (VACNTs) show unique mechanical behavior in compression, with a highly nonlinear response similar to that of open cell foams and the ability to recover large deformations. Here, we study the viscoelastic response of both freestanding VACNT arrays and sandwich structures composed of a VACNT array partially embedded between two layers of poly(dimethylsiloxane) (PDMS) and bucky paper. The VACNTs tested are similar to 2 mm thick foams grown via an injection chemical vapor deposition method. Both freestanding and sandwich structures exhibit a time-dependent behavior under compression. A power-law function of time is used to describe the main features observed in creep and stress-relaxation tests. The power-law exponents show nonlinear viscoelastic behavior in which the rate of creep is dependent upon the stress level and the rate of stress relaxation is dependent upon the strain level. The results show a marginal effect of the thin PDMS/bucky paper layers on the viscoelastic responses. At high strain levels (epsilon - 0.8), the peak stress for the anchored CNTs reaches similar to 45 MPa, whereas it is only similar to 15MPa for freestanding CNTs, suggesting a large effect of PDMS on the structural response of the sandwich structures. (C) 2012 American Institute of Physics. http://dx.doi.org/10.1063/1.3699184]

Item Type: Journal Article
Publication: Journal of Applied Physics
Publisher: American Institute of Physics
Additional Information: Copyright for this article belongs to the American Institute of Physics
Department/Centre: Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited: 16 Jun 2012 08:57
Last Modified: 16 Jun 2012 08:57
URI: http://eprints.iisc.ac.in/id/eprint/44667

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