Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Mechanical properties of carbon nanotubes and nanofibers
Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. (Fysik)
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Carbon nanotubes (CNTs) have extraordinary electrical and mechanical properties, and many potential applications have been proposed, ranging from nanoscale devices to reinforcement of macroscopic structures. However, due to their small sizes, characterization of their mechanical properties and deformation behaviours are major challenges. Theoretical modelling of deformation behaviours has shown that multi-walled carbon nanotubes (MWCNTs) can develop ripples in the walls on the contracted side when bent above a critical curvature. The rippling is reversible and accompanied by a reduction in the bending stiffness of the tubes. This behaviour will have implications for future nanoelectromechanical systems (NEMS). Although rippling has been thoroughly modelled there has been a lack of experimental data thus far. In this study, force measurements have been performed on individual MWCNTs and vertically aligned carbon nanofibers (VACNFs). This was accomplished by using a custom-made atomic force microscope (AFM) inside a scanning electron microscope (SEM). The measurements were done by bending free-standing MWCNTs/VACNFs with the AFM sensor in a cantilever-to-cantilever fashion, providing force-displacement curves. From such curves and the MWCNT/VACNF dimensions, measured from SEM-images, the critical strain for the very onset of rippling and the Young’s modulus, E, could be obtained. To enable accurate estimations of the nanotube diameter, we have developed a model of the SEM-image formation, such that intrinsic diameters can be retrieved. We have found an increase in the critical strain for smaller diameter tubes, a behaviour that compares well with previous theoretical modelling. VACNFs behaved very differently, as they did not display any rippling and had low bending stiffnesses due to inter-wall shear. We believe that our findings will have implications for the design of future NEMS devices that employ MWCNTs and VACNFs.

Place, publisher, year, edition, pages
Karlstad: Karlstad University Press, 2012. , 60 p.
Series
Karlstad University Studies, ISSN 1403-8099 ; 2012:18
Keyword [en]
atomic force microscopy, bending, carbon nanotubes, deformation, scanning electron microscopy, Young's modulus, carbon nanofibers, mechanical properties
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
URN: urn:nbn:se:kau:diva-12925ISBN: 978-91-7063-422-2 (print)OAI: oai:DiVA.org:kau-12925DiVA: diva2:517153
Presentation
2012-06-08, 21A342, Karlstads universitet, Karlstad, 10:15 (English)
Opponent
Supervisors
Funder
Swedish Research Council, 2010-4324
Note

Artikel 2 Image formation mechanisms tidigare som manuskript, nu publicerad: urn:nbn:se:kau:diva-16425 (MÅ 150924)

Available from: 2012-05-24 Created: 2012-04-16 Last updated: 2015-09-24Bibliographically approved
List of papers
1. Measurements of the critical strain for rippling in carbon nanotubes
Open this publication in new window or tab >>Measurements of the critical strain for rippling in carbon nanotubes
2011 (English)In: Applied Physics Letters, ISSN 0003-6951, Vol. 98, no 18, 3 pages- p.Article in journal (Refereed) Published
Abstract [en]

We report measurements of the bending stiffness in free standing carbon nanotubes, using atomic force microscopy inside a scanning electron microscope. Two regimes with different bending stiffness were observed, indicative of a rippling deformation at high curvatures. The observed critical strains for rippling were in the order of a few percent and comparable to previous modeling predictions. We have also found indications that the presence of defects can give a higher critical strain value and a concomitant reduction in Youngs modulus.

Place, publisher, year, edition, pages
American Institute of Physics, 2011
Keyword
Carbon nanotubes, mechanical properties, rippling, atomic force microscopy (AFM), scanning electron microscopy (SEM)
National Category
Materials Engineering Physical Sciences
Research subject
Materials Engineering; Physics
Identifiers
urn:nbn:se:kau:diva-10738 (URN)10.1063/1.3587613 (DOI)000290392300048 ()
Available from: 2012-02-08 Created: 2012-02-08 Last updated: 2017-12-06Bibliographically approved
2. Image formation mechanisms in scanning electron microscopy of carbon nanotubes,and retrieval of their intrinsic dimensions.
Open this publication in new window or tab >>Image formation mechanisms in scanning electron microscopy of carbon nanotubes,and retrieval of their intrinsic dimensions.
2013 (English)In: Ultramicroscopy, ISSN 0304-3991, Vol. 124, 35-39 p.Article in journal (Refereed) Published
Abstract [en]

We present a detailed analysis of the image formation mechanisms that are involved in the imaging of carbon nanotubes with scanning electron microscopy (SEM). We show how SEM images can be modelled by accounting for surface enhancement effects together with the absorption coefficient for secondary electrons, and the electron-probe shape. Images can then be deconvoluted, enabling retrieval of the intrinsic nanotube dimensions. Accurate estimates of their dimensions can thereby be obtained even for structures that are comparable to the electron-probe size (on the order of 2 nm). We also present a simple and robust model for obtaining the outer diameter of nanotubes without any detailed knowledge about the electron-probe shape.

Place, publisher, year, edition, pages
Elsevier, 2013
Keyword
Scanning electron microscopy; Carbon nanotubes; Imaging mechanisms; Deconvolution; Electron-probe shape
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-16425 (URN)10.1016/j.ultramic.2012.08.012 (DOI)000311823700006 ()23142742 (PubMedID)
Funder
Swedish Research Council, 2010-4324
Available from: 2014-02-21 Created: 2013-01-18 Last updated: 2015-09-24Bibliographically approved
3. Direct measurement of bending stiffness and estimation of Young’s modulus of vertically aligned carbon nanofibers
Open this publication in new window or tab >>Direct measurement of bending stiffness and estimation of Young’s modulus of vertically aligned carbon nanofibers
Show others...
2013 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, no 19Article in journal (Refereed) Published
Abstract [en]

We have measured the bending stiffness of as-grown vertically aligned carbon nanofibers using atomic force microscopy inside a scanning electron microscope. We show that the assumption of a uniform internal structure is inadequate in describing nanofibers mechanical properties and that a dual phase model is needed. We present a model in which different Young’s moduli are assigned to the inner graphitic core and the outer amorphous carbon shell and show that it provides a better fit to the measurements. We obtain values of 11±8 GPa and 63±14 GPa for the Young’s modulus of the inner core and the outer shell, respectively.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2013
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-13391 (URN)10.1063/1.4803853 (DOI)000319295200052 ()
Available from: 2012-05-28 Created: 2012-05-28 Last updated: 2017-08-11Bibliographically approved

Open Access in DiVA

KUS_2012_18(1721 kB)401 downloads
File information
File name FULLTEXT02.pdfFile size 1721 kBChecksum SHA-512
fb9c67f2d8e22bb42741453a2b42c58796d3f48e531a7a4a539b3e4419693bdd55f6d27d33ba33993b40a8c584725f85cbdcfedfe162a58a031c9c924fe26337
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Jackman, Henrik
By organisation
Department of Physics and Electrical Engineering
Condensed Matter Physics

Search outside of DiVA

GoogleGoogle Scholar
Total: 460 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 327 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf