RIVERSIDE, Calif., May 19, 2006 -- Even the smallest devices, assembled at the molecular level, need motors and oscillators in order to work. University of California Riverside Mechanical Engineering Professor Qing Jiang said his recent findings show bundling groups of carbon nanotubes together could make an ultra-efficient and accurate nano-oscillator.
In the rapidly developing field of nanotechnology, nanodevices are becoming an increasingly key component in everything from drug delivery to improving or even replacing the microprocessors in computers or optical switches in telecommunications networks, Jiang said.
“A nano-oscillator itself is a vitally important device or component for nanosystems, in which some parts have to experience relative motion of frequencies beyond one gigahertz (a billion cycles per second), a frequency range currently inaccessible by mechanical systems. Therefore, developing gigahertz nano-oscillators is recognized as a milestone in the roadmap of molecular manufacturing,” Jiang said.
“We’re looking at the very fundamentals of machinery in the nanoscopic world and what it takes to move the components of these machines, ultrafast, super-efficient and with extreme precision,” Jiang said. “A nanomotor generating rotational motion, a nano-oscillator (like a piston) generating linear motion forward and backward. We’re looking at how best to generate these motions in a nano-environment.”
Currently, oscillators are designed using what are called multiwalled carbon nanotubes, in which one tube is encased into another and a tiny electronic charge causes it to cycle in and out -- similar to how pistons in a shock adsorber work. Jiang’s earlier work, done mostly with these multiwalled carbon nanotube oscillators, encountered two limitations -- frequency and friction. With increased frequency, beyond the benchmark 1 Ghz, increased energy dissipation creates a lot of heat, which reduces the efficiency of the tiny pistons.
His current work, with bundles of single-walled carbon nanotubes encased in an additional layer of single-walled carbon nanotubes outperformed their multiwalled counterparts and generated less heat and friction problems.
“We were very encouraged by the findings of this paper and think we may be on our way to developing efficient oscillators,” Jiang said. However, Jiang and his colleagues plan on exploring new substances that could better address the friction and heat limitations that carbon nanotubes encounter.
Jiang's findings were published in the May 14 issue of the Institute of Physics journal Nanotechnology, in a paper titled "Nanotube Oscillator Based on a Short Single-Walled Carbon Nanotube Bundle," co-authored with colleagues Jeon Won Kang, Ki Oh Song and Ho Jun Hwang from Chung-Ang University, Seoul, South Korea.
For more information, visit: www.ucr.edu