Wei, Haoyan and Kim, Sang Nyon and Zhao, Minhua and Ju, Sang-Yong and Huey, Bryan D. and Marcus, Harris L. and Papadimitrakopoulos, Fotios (2008) Control of length and spatial functionality of single-wall carbon nanotube AFM nanoprobes. CHEMISTRY OF MATERIALS, 20 (8). pp. 2793-2801.
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Official URL: http://pubs.acs.org/doi/abs/10.1021/cm7031465
Single-wall carbon nanotube (SWNT) nanotibrils were assembled onto conductive atomic force microscopy (AFM) probes with the help of dielectrophoresis (DEP). This process involved the application of a 10 V, 2 MHz, AC bias between a metal-coated AFM probe and a dilute suspension of SWNTs. This exerted a positive dielectrophoretic force onto the nanotubes that caused them to align while precipitating out onto the probe. The gradual removal of the AFM probe away from the SWNT suspension consolidated these nanotubes into nanofibrils with a high degree of alignment as demonstrated with polarization Raman experiments. By varying the pulling speed, immersion time, and concentration of the SWNT suspension, one can tailor the diameter and thus the stiffness of these probes. Precise length trimming of these nanofibrils was also performed by their gradual immersion and dissolution into a liquid that strongly interacted with nanotubes, (i.e., sodium dodecyl sulfate (SDS) solution). Vacuum annealing these nanoprobes at temperature up to 450 degrees C further increased their stiffness and rendered them insoluble to SDS and all other aqueous media. Regrowth of a new SWNT nanofibril from the side or at the end of a previously grown SWNT nanotibril was also demonstrated by a repeated dielectrophoretic assembly at the desired immersion depth. These SWNT nanofibril-equipped AFM probes are electrically conductive and mechanically robust for use as high-aspect-ratio electrochemical nanoprobes.
|Subjects:||Analytical Science > Microscopy and probe methods|
Material Science > Functional and hybrid materials
Physical Science > Nano objects
|Deposited On:||20 Jan 2009 12:15|
|Last Modified:||29 Jan 2009 16:56|
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