Polymer materials are usually thermal insulators, but the researchers in the United States through the electropolymerization process to arrange the polymer fibers in a neat array to form a new thermal interface material, the thermal conductivity is 20 times higher than the original. The new material is reliable at temperatures up to 200 ° C and can be used in heat sinks to help dissipate heat from electronic devices in servers, automotive, and high-brightness LEDs. The research results were published in advance in the recent "Nature. Nanotechnology magazine online edition. As electronic devices become more powerful and smaller, the heat dissipation problem becomes more and more complicated. Engineers are always looking for better thermal interface materials to help electronic devices dissipate heat. Amorphous polymeric materials are poor conductors of heat because their disordered state limits the transfer of thermally conductive phonons. Although the thermal conductivity can be improved by creating a neatly arranged crystal structure in the polymer, these structures are formed by a fiber drawing process, which causes the material to be brittle. Georgia Institute of Technology George. Assistant Professor of the Woodruff Institute of Mechanical Engineering, Baratud. Carla said that the new thermal interface material is made of conjugated polymer polythiophene, and its neat nanofiber array not only facilitates the transfer of phonons, but also avoids the brittleness of the material. The new material has a thermal conductivity of 4.4 watts/meter at room temperature. Kelvin, which has been tested for 80 cycles at 200 ° C, the performance is still stable; in contrast, the solder material commonly used in the thermal interface between the chip and the heat sink may work during the high temperature of the reflow process. Become unreliable. The nanofiber array structure was fabricated in multiple steps: the researchers first applied the monomer-containing electrolyte to an alumina template with tiny pores and then applied an electrical potential to the template, and the electrodes in each pore attracted. Monomers begin to form hollow nanofibers. The length and wall thickness of the fibers are controlled by the amount of current applied and the time, and the diameter of the fibers is determined by the size of the pores, ranging from 18 nm to 300 nm. Conventional thermal interface materials have a thickness of from about 50 microns to about 75 microns, and new materials obtained in this manner can be as thin as 3 microns. Carat said that the technology still needs further improvement, but he believes that production and commercialization can be expanded in the future. Materials with such high reliability are attractive for solving heat dissipation problems. This material may eventually change the way we design electronic systems.
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