Sun Rong research team of Shenzhen Advanced Institute has made a series of progress in the field of high performance thermal conductive composite materials

Recently, the research team of sun Rong, advanced materials center, Shenzhen Institute of advanced technology, Chinese Academy of Sciences, has made a series of progress in the field of high-performance thermal conductive composite materials With the development of modern electronic devices to high integration and high power, if the heat generated in the device is not effectively distributed, it will cause thermal failure To solve the problem of heat dissipation depends on the development of thermal management materials Heat conducting materials are usually composed of heat conducting fillers and polymer matrix Solution blending is a common method to prepare composite materials with randomly distributed fillers However, due to the lack of effective interconnection between the inner fillers, the improvement rate of thermal conductivity of the composite is usually very low The lack of heat conduction path composed of fillers means that phonons will generate more heat dissipation at the interface between fillers and matrix, which will lead to greater interface thermal resistance On the other hand, adding a large number of fillers (> 60wt% / vol%) will get ideal thermal conductivity, but it will seriously affect the mechanical properties and processability of the composite, which is difficult to be applied Therefore, how to achieve high thermal conductivity at a lower filler content is still a big challenge Mo Yimin, Zeng Xiaoliang, etc of the heat conduction team of the team prepared macro oriented silicon carbide wire network by using ice template method through the structural design of orientation of the filler, combined with the high thermal conductivity and length diameter ratio of silicon carbide nanowires, and prepared high thermal conductivity composite materials using this as the filler For phonons, the most convenient way to pass through a polymer is to establish a channel composed of fillers inside the polymer Therefore, polymer composites with high conductivity hot wire fillers will show a great improvement in thermal conductivity The heat conduction efficiency of the composite is 3-8 times higher than that of other reported heat conduction and insulation composite The high heat conduction composite with three-dimensional interconnection packing network inside has great application potential in the field of heat management Related papers were published online in ACS Applied Materials & interfaces (if = 7.504) (DOI: 10.1021 / acsami 8b00328) The team has also made progress in the construction of three-dimensional boron nitride graphene heat conduction network In order to make the three-dimensional packing skeleton have certain mechanical strength, the former researchers usually need to add binder in the preparation process of the three-dimensional skeleton However, the mismatch of the phonon spectrum between the binder and the filler will weaken the heat transfer of the filler framework itself, so the thermal conductivity of polymer matrix composites with three-dimensional filler framework is often not ideal The project team took boron nitride and graphene, which have similar phonon transmission properties, as the assembly units, and constructed the oriented phonon heat conduction network The out of plane thermal conductivity of the composite reaches 5.05 wm-1k-1, which is higher than that of other reported boron nitride based composites Related papers were published online in Journal small (if = 8.643) (DOI: 10.1002 / small 201704044) The group also proposed a novel material forming method Limited by the cost and production equipment, vacuum assisted filtration technology and ice template self-assembly technology are difficult to achieve industrialization and contribute to China's electronic materials industry Therefore, Zeng Xiaoliang's research group explored and invented a simple, rapid and macro preparation method of thermal conductive filler Three dimensional aerogel spherical packing can be successfully constructed by directly pouring liquid dispersion containing filler into liquid nitrogen, combining freeze-drying and simple automatic propulsion device This kind of spherical packing has large porosity and specific surface area, which is directly involved in the construction of heat conduction network, can effectively improve the thermal conductivity of composite materials, and can achieve small-scale production in laboratory with the help of automatic propulsion device In addition, this special microstructure also shows great potential in adsorption and energy fields Related papers were published online in Journal of Materials Chemistry A (if = 8.867) (DOI: 10.1039 / c8ta00310f) The above research was supported by key R & D projects of the Ministry of science and Technology (2017yfb0406000), Guangdong innovation research team (2011d052), Guangdong Key Laboratory (2014b030301014) and Shenzhen Science and technology program