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.
Hubble sees Neptune's mysterious shrinking storm
16.02.2018 | NASA/Goddard Space Flight Center
Supermassive black hole model predicts characteristic light signals at cusp of collision
15.02.2018 | Rochester Institute of Technology
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).
Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
16.02.2018 | Information Technology
16.02.2018 | Health and Medicine
16.02.2018 | Physics and Astronomy