Carbon nanotubes are attractive candidates for use as the active elements in the next generation of electronic devices. However, it has proven incredibly difficult to align nanotubes within device architectures.
Most of the approaches for lining up carbon nanotubes reported until now are only applicable to discrete devices and are not readily scalable to the levels required for the mass production of nanotube-based chips. Now, this seemingly intractable problem has been overcome by a collaborative team of researchers from Seoul National University and Sungkyunkwan in South Korea.
Kahp Suh and his colleagues have developed a technique for aligning nanotubes over large areas based on the flow of a nanotube-containing solution through nanochannels. This technique is especially attractive because of its simplicity; no external stimuli such as the application of an electric field or syringe pumping are required to align the nanotubes.
This novel approach for aligning carbon nanotubes is based on the simple flow of a nanotube solution through a nanochannel fabricated from a charged polymeric mold. The nanotubes are ordered within the channels by the influence of the capillary force existing within the confines of the channel. When the channels are of the correct geometry, aqueous solutions containing nanotubes enter from both ends, and upon evaporation leave behind dense and highly oriented arrays of nanotubes.
Suh cautions that the mechanical properties and surface chemistry of the polymeric mold used for making the nanochannels are of paramount importance. “The stiffness of the polymer has to be just right”, says Suh, “it has to be rigid enough to keep the nanochannels from collapsing but flexible enough to bond well with the substrate over a large area”. Good adhesion is required between the nanochannel and the substrate to prevent the polymer nanochannels from coming unstuck upon the introduction of the aqueous nanotube solution. The researchers have found that polyethylene glycol diacrylate has the right combination of properties for use as the polymer mold. It is negatively charged and facilitates conformal contact with the substrate. Moreover, it is hydrophilic and thus the nanotube solution is able to enter and flow through the channels without need for additional pumping.
Suh further added that this approach represents a promising advance for the integration of nanotubes in microscale devices. The use of fluidics to bring typically unruly bundles of nanotubes into line may help to solve prevailing bottlenecks for scaling up the production of nanotube devices.
Author: Kahp Y. Suh, Seoul National University (South Korea), http://mae.snu.ac.kr/eng/about/pview.asp?pid=48
Title: Capillarity-Driven Fluidic Alignment of Single-Walled Carbon Nanotubes in Reversibly Bonded Nanochannels
Small 2008, 4, No. 1, 92–95, doi: 10.1002/smll.200700300
About Small: Micro and Nano: No small Matter. Science at the nano- and microscale is currently receiving enormous wordwide interest. Published by Wiley-VCH, Small provides the very best forum for experimental and theoretical studies of fundamental and applied interdisciplinary research at these dimensions. Read an attractive mix of peer-reviewed Communications, Reviews, Concepts, Highlights, Essays, and Full Papers.
Spinning rugby balls: The rotation of the most massive galaxies
23.05.2018 | Leibniz-Institut für Astrophysik Potsdam
Turning entanglement upside down
23.05.2018 | Universität Innsbruck
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
23.05.2018 | Physics and Astronomy
23.05.2018 | Agricultural and Forestry Science
23.05.2018 | Physics and Astronomy