Engineers have created carpets made of carbon nanotubes to enhance the flow of heat where computer chips connect to heat sinks. Researchers are trying to develop new types of thermal interface materials that conduct heat more efficiently than conventional materials, improving overall performance and helping to meet cooling needs of future chips that will produce more heat than current microprocessors. Purdue University researchers have made several new thermal interface materials with carbon nanotubes, including a Velcro-like nanocarpet.



"The bottom line is the performance that we see with nanotubes is significantly better than comparable state-of-the-art commercial materials," said Timothy Fisher, an associate professor of mechanical engineering who is leading the research. "Carbon nanotubes have excellent heat-conduction properties, and our ability to fabricate them in a controlled manner has been instrumental in realizing this application."



Recent findings have shown that the nanotube-based interfaces can conduct several times more heat than conventional thermal interface materials at the same temperatures. The nanocarpet, called a "carbon nanotube array thermal interface," can be attached to both the chip and heat sink surfaces. As heat flows through conventional thermal interface materials, the temperature rises about 15°C, whereas the nanotube array material causes a rise of about 5°C. The nanotubes range in diameter from less than 1 nm to about 100 nm.



The nanotube carpets also might have military and other commercial applications for cooling power electronics. The research has been funded by Purdue's Cooling Technologies Research Center, supported by the National Science Foundation, industry and Purdue to help corporations develop miniature cooling technologies for a wide range of applications, from electronics and computers to telecommunications and advanced aircraft.



Applications in power electronics are being supported by the Air Force Research Laboratory in association with the Birck Nanotechnology Center at Purdue's Discovery Park. The technology is ready for commercialization and is being pursued by several corporate members of the cooling research center.