The mechanical properties of individual multiwall boron nitride nanotubes (MWBNNTs) synthesized by a growth-vapor-trapping chemical vapor deposition method are investigated by a three-point bending technique via atomic force microscopy. Multiple locations on suspended tubes are probed in order to determine the boundary conditions of the supported tube ends. The bending moduli (EB) calculated for 20 tubes with diameters ranging from 18 to 58 nm confirm the exceptional mechanical properties of MWBNNTs, with an average EB of 760 ± 30 GPa. For the first time, the bending moduli of MWBNNTs are observed to increase with decreasing diameter, ranging from 100 ± 20 GPa to as high as 1800 ± 300 GPa. This diameter dependence is evaluated by Timoshenko beam theory. The Young's modulus and shear modulus were determined to be 1800 ± 300 and 7 ± 1 GPa, respectively, for a trimmed data set of 16 tubes. The low shear modulus of MWBNNTs is the reason for the detected diameter-dependent bending modulus and is likely due to the presence of interwall shearing between the crystalline and faceted helical nanotube structures of MWBNNTs.
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http://dx.doi.org/10.1021/jp308893s | DOI Listing |
Nanomaterials (Basel)
December 2019
Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1 Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan.
Fiber-type dye-sensitized solar cells (FDSSCs) are attractive as an energy source of soft electronics due to low-costs, non-toxicity and especially, their indoor-weak-light workable features. The TiO nanotube array (TNA) can grow on flexible Ti wires directly using anodization technique, which is convenient and can provide better contact between substrate/TiO. However, a systematic study of assembling efficient TNA on photoanode of FDSSC is limited.
View Article and Find Full Text PDFJ Phys Chem B
April 2013
Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
The mechanical properties of individual multiwall boron nitride nanotubes (MWBNNTs) synthesized by a growth-vapor-trapping chemical vapor deposition method are investigated by a three-point bending technique via atomic force microscopy. Multiple locations on suspended tubes are probed in order to determine the boundary conditions of the supported tube ends. The bending moduli (EB) calculated for 20 tubes with diameters ranging from 18 to 58 nm confirm the exceptional mechanical properties of MWBNNTs, with an average EB of 760 ± 30 GPa.
View Article and Find Full Text PDFACS Nano
April 2010
Department of Chemical Engineering, Texas Materials Institute, and Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, Austin, Texas 78712-1062, USA.
The mechanical strengths of individual germanium (Ge) nanowires with 111 growth direction and diameters ranging from 23 to 97 nm were measured by bending each with a robotic nanomanipulator in a scanning electron microscope (SEM). The nanowires tolerate diameter-dependent flexural strains of up to 17% prior to fracture, which is more than 2 orders of magnitude higher than bulk Ge. The corresponding bending strength of 18 GPa is in agreement with the ideal strength of 14-20 GPa for a perfect Ge crystal.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
August 2009
Departments of Chemical and Biomolecular Engineering and Chemistry, NanoCarbon Center, Center for Biological and Environmental Nanotechnology, and RE Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, TX 77005, USA.
By relating nanotechnology to soft condensed matter, understanding the mechanics and dynamics of single-walled carbon nanotubes (SWCNTs) in fluids is crucial for both fundamental and applied science. Here, we study the Brownian bending dynamics of individual chirality-assigned SWCNTs in water by fluorescence microscopy. The bending stiffness scales as the cube of the nanotube diameter and the shape relaxation times agree with the semiflexible chain model.
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