Researchers from Xi'an Jiaotong University (XJTU) have proposed a bionic design idea based on the multi-scale structure of wood.

Inspired by the "brick-mud" layered structure of mother-of-pearl shells, an anisotropic silicon carbide thermally conductive framework was constructed in an epoxy resin matrix using a biotemplate ceramization technique combined with a vacuum impregnation method.

The 3D framework has a high degree of alignment in the axial direction, and the adjacent nano-SiC grains inside it are in close contact with low interfacial thermal resistance. The framework has a honeycomb network in the radial direction that restricts the thermal motion of polymer chains structure.

 With the high thermal conductivity of SiC and the characteristics of bionic structure, the composite material achieves an extremely low radial thermal expansion coefficient, excellent thermal stability and flame retardancy while achieving an effective increase in axial thermal conductivity.

The research results were published in Advanced Science under the title of Wood-Derived, Vertically Aligned and Densely Interconnected 3D SiC Frameworks for Anisotropically Highly Thermoconductive Polymer Composites. (Link to the paper: https://doi.org/10.1002/advs.202103592)

The State Key Laboratory of Mechanical Behavior of Materials is the first author unit. Associate Professor Wang Bo and Professor Yang Jianfeng of Ceramic Engineering Technology Research Center of Shaanxi Province are the corresponding authors of this paper. 

The first author is Zhou Xiaonan, a doctoral student. The main collaborators include Professor Zhang Qiaogen and Associate Professor Zhao Junping from the School of Electrical Engineering.

The project was funded by the National Natural Science Foundation of China.

With the continuous development of 5G communication and artificial intelligence electronic devices in the direction of miniaturization, integration and multi-function, the problem of efficient heat dissipation has become a bottleneck restricting the development and application of microelectronic devices and their systems.

New polymer thermally conductive composites are required to have a low thermal expansion coefficient, high thermal conductivity and thermal stability at the same time. The traditional method of adding randomly dispersed thermally conductive fillers to the polymer matrix not only has limited thermal conductivity enhancement efficiency, but also will greatly increase the difficulty of the process and reduce the mechanical properties of the material.