Ultrahigh thermal conductive polymer composites by the 3D printing induced vertical alignment of carbon fiber

As the power density increases in electronic devices, requirements for high-performance thermal interface materials that can efficiently bridge the heat transport channel between the heat sink and the target electronics have become much more urgent. Despite extensive efforts, the scalable manufacturing of advanced thermal interface materials featuring high thermal conductivity and low interfacial thermal resistance at low cost remains challenging. We proposed a 3D printing (direct ink writing) method for aligning carbon fibers in this work. By slicing the composites perpendicular to the direction of carbon fibers, we can conveniently manufacture thermal interface materials with a high through-plane thermal conductivity of 35.22 W m⁻¹ K⁻¹, which is 1213 times higher than that of the PDMS matrix. Meanwhile, our carbon fiber based thermal interface materials show a 17.4 °C drop than the advanced commercial thermal interface materials, when used in TIM performance test devices, exhibiting significantly enhanced cooling efficiency. This work offers valuable insight into the structural design of highly thermally conductive composites and demonstrates the possibility of its practical applications in the thermal management of electronics.