repost from: http://www.cobledbulb.com
Polymeric materials are usually for thermal insulator, but U.S. researchers make the polymer fibers arranged in neat array by electro-polymerization, forming a new type of thermal interface material, thermal performance improved 20-fold based on the original. The new material can be reliable operation at a temperature up to 200 ℃. It can be used for cooling high-brightness LED, automobiles, electronic equipment and internet server. The research achievement is published in "Nature Nanotechnology" magazine online edition.
As electronic devices became more powerful, smaller size, thermal issues are becoming increasingly complex. Engineers have been looking for better thermal interface materials, to help electronic devices dissipate heat effectively. The amorphous polymer material is a poor conductor of heat, since their disorder limit the heat conduction phonon transfer.
Assistant Professor, Georgia Institute of Technology, George Woodruff School of Mechanical Engineering Balatude carat says, new thermal interface material made of conjugated polymers, which is not only neat nanofiber arrays conducive phonon transition, but also to avoid brittle material.
The thermal conductivity of new material will at room temperature of 4.4 watts / meter Kelvin. And has been conducted 80 times heat cycle test at a temperature of 200 ℃, the performance remains stable.
Nanofiber array structure is manufactured by a plurality of steps. Researchers first monomer containing an electrolyte is coated on a template with minute pores of the alumina, and then applying an electrical potential to the template, each of the apertures in the electrodes will attract the monomers, the formation of the hollow nanofiber.
The length and thickness of the fibers are control by the amount of current and time. the size of the pores ranging from 18 nm to 300 nm determines by the diameter of the fiber. Traditional thermal interface material thickness of about 50 microns to 75 microns and the thickness of the new material obtained in this manner can be as thin as 3 microns.
Carat said the technology still needs further improvement, but he believes it will be able to expand production and commercialization.
