14 DAY TRIAL // Changing the thermal and electrical conductivity of certain materials is definitely possible, say experts at the Massachusetts Institute of Technology, who recently managed to demonstrate a method of doing just that. Their work provides a new approach to influencing the properties of materials.
Causing these traits to change is an easy endeavor, the group explains. All scientists had to do to obtain this effect was to change the conditions in which the materials were kept (their environment).
What's more, the MIT group determined that this approach changed electrical conductivity by a factor of as much as 100. On the other hand, thermal conductivity is only changed threefold from the original.
The work was carried out with support from scientists at the Beijing Normal University (BNU) and the South China Normal University (SCNU). Part of the funds required to carry out the investigation were provided by the US National Science Foundation (NSF).
Details of the research were published in the April 19 online issue of the top journal Nature Communications, and are also scheduled to appear in an upcoming print issue of the same magazine.
The senior author of the paper was the MIT Carl Richard Soderberg professor of power engineering Gang Chen, who is also the director of the Pappalardo Micro and Nano Engineering Laboratories.
“It’s a new way of changing and controlling the properties” of materials, he explains, referring to a special class of compounds called percolated composite materials. BNU expert Ruiting Zheng, SCNU scientist Jinwei Gao and MIT graduate student Jianjian Wang were the lead authors of the research.
According to the research group, thermal or electrical applications are the primary targets for this innovation. They are hoping that colleagues from the international scientific community will step in and decide to use this approach for various devices.
“I think this is a very crucial result. Heat switches exist, [but] here we have a system with no macroscopic moving parts. This is excellent work,” adds expert Joseph Heremans.
The expert, who is a professor of physics and of mechanical and aerospace engineering at the Ohio State University, adds that other heat switches are made from multiple parts, themselves fashioned out of different materials.
“Using phase change to control the conductivity of nanocomposites is a very clever idea,” comments University of Texas in Austin mechanical engineering professor Li Shi, who was not a part of the research team.