Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Physics
Phase Imaging: Deep Or Superficial?, Nancy Burnham, O Behrend, L Odoni, J Loubet
Phase Imaging: Deep Or Superficial?, Nancy Burnham, O Behrend, L Odoni, J Loubet
Nancy A. Burnham
Phase images acquired while intermittently contacting a sample surface with the tip of an atomic force microscope cantilever are not easy to relate to material properties. We have simulated dynamic force curves and compared simulated with experimental results. For some cantilever–sample combinations, the interaction remains a surface effect, whereas for others, the tip penetrates the sample significantly. Height artifacts in the “topography” images, and the role of the sample stiffness, work of adhesion, damping, and topography in the cantilever response manifest themselves to different extents depending on the indentation depth.
Elastic And Shear Moduli Of Single-Walled Carbon Nanotube Ropes, Nancy Burnham, Jean-Paul Salvetat, G Andrew D Briggs, Jean-Marc Bonard, Revathi Bacsa, Andrzej Kulik, Thomas Stöckli, László Forró
Elastic And Shear Moduli Of Single-Walled Carbon Nanotube Ropes, Nancy Burnham, Jean-Paul Salvetat, G Andrew D Briggs, Jean-Marc Bonard, Revathi Bacsa, Andrzej Kulik, Thomas Stöckli, László Forró
Nancy A. Burnham
Carbon nanotubes are believed to be the ultimate low-density high-modulus fibers, which makes their characterization at nanometer scale vital for applications. By using an atomic force microscope and a special substrate, the elastic and shear moduli of individual single-walled nanotube (SWNT) ropes were measured to be of the order of 1 TPa and 1 GPa, respectively. In contrast to multiwalled nanotubes, an unexpectedly low intertube shear stiffness dominated the flexural behavior of the SWNT ropes. This suggests that intertube cohesion should be improved for applications of SWNT ropes in high-performance composite materials.