Scientists at RMIT University in Australia have released research that demonstrates a new method of heat dissipation on the nanoscale level.
In a paper published in the online journal Advanced Energy Materials, Kourosh Kalantar-zadeh, a professor at the School of Electrical and Computer Engineering, and his colleagues demonstrate the “on-demand” creation of tiny nanofin heat sinks near computer chip hot spots that serve as an intermediary between the hot spot and a microfluidic system to draw heat away from the chip.
“People have [previously] used nanoparticles in microfluidics to increase the thermal conductivity of liquid,” Kalantar-zadeh told Nanowerk News. “However, there are limitations. The concentration of nanoparticles cannot exceed two to three percent of the total weight of the liquid-particle mixture, or else it clogs the channel. Using our method, we increase the concentration of nanoparticles only near the hot spots and form the desired nanofins, while the overall concentration of nanoparticles in the mucrofluidic can be as small as 0.01 percent.”
The research team observed that upon exposing ferromagnetic chromium oxide (CrO2) nanoparticles to a magnetic field for approximately five minutes, the nanoparticles grew about 1,600 times their original length, from about 200 nm to 320 µm. Removing the magnetic field caused the nanoparticles to begin shrinking back to their original size.
“We disperse these nanoparticles in microfluidics that are formed around the IC chips and we can establish nanofins from them on demand,” explained Pyshar Yi, a Ph.D candidate in Kalantar-zadeh ‘s group and first author of the paper. “These nanofin structures are thermally conductive, and absorb the generated heat from the hot spots. They do two things in their operation: they release heat efficiently into the flow of liquid around them; and they can also be released on demand to take the heat with them and release them somewhere else.”
While the primary use of these nanofins would be for cooling IC chips, the researchers say, they can be used for other applications as well, including microelectronic industry processes, mobile handsets, military devices and even clothing with embedded cooling systems.
“Our work is a proof of concept and the performance of the systems should be improved,” Khashayar Khoshmanesh, Ph.D, who co-wrote the paper as first author with Yi, told Nanowerk News. “Higher flow rates, while maintaining the high aspect ratio nanofin structure, are the key to increase the efficiency and with more advanced designs this can be achieved.”
