A Roadmap Review of Thermally Conductive Polymer Composites: Critical Factors, Progress and Prospects

Recently, the need for miniaturization and high integration have steered a strong technical wave in designing and developing (micro-)electronic devices. With the continuous increase in power requirements, excessive amounts of heat may be generated during operation/charging, severely affecting device performance and potentially leading to life/property loss. Benefiting from their low density, easy processing and low manufacturing cost, thermally conductive polymer composites have become a research hotspot as a media to mitigate the disadvantages of excessive heat, to be used in areas such as 5G communication, electronic packaging and energy transmission. However, the thermal conductivity coefficients (λ) of reported thermally conductive polymer composite are far from expectation. Deeper understanding of heat transfer mechanisms is highly desired for developing next generation materials for thermally conductive composites. From this perspective, this review holistically scopes current advances in this field, while giving special attention to critical factors that affect thermal conductivity in polymer composites as well as the thermal conduction mechanisms on how to enhance the λ value. Specifically, this review covers these critical factors, including interfacial thermal resistance, chain structure of polymer, intrinsic λ value of different thermally conductive fillers, orientation/configuration of nanoparticles, 3D interconnected networks, processing technology, etc. Finally, the applications of thermally conductive polymer composites in electronic devices are summarized. The existing problems are also discussed and new challenges and opportunities for the future are prospected.