Tetris-Style Stacking Process to Tailor the Orientation of Carbon Fiber Scaffolds for Efficient Heat Dissipation

Abstract

As the miniaturization of electronic devices and complication of electronic packaging, there are growing demands for thermal interfacial materials with enhanced thermal conductivity and the capability to direct the heat toward heat sink for highly efficient heat dissipation. Pitch-based carbon fiber (CF) with ultrahigh axial thermal conductivity and aspect ratios exhibits great potential for developing thermally conductive composites as TIMs. However, it is still hard to fabricate composites with aligned carbon fiber in a general approach to fully utilize its excellent axial thermal conductivity in specific direction. Here, three types of CF scaffolds with different oriented structure were developed via magnetic field-assisted Tetris-style stacking and carbonization process. By regulating the magnetic field direction and initial stacking density, the self-supporting CF scaffolds with horizontally aligned (HCS), diagonally aligned and vertically aligned (VCS) fibers were constructed. After embedding the polydimethylsiloxane (PDMS), the three composites exhibited unique heat transfer properties, and the HCS/PDMS and VCS/PDMS composites presented a high thermal conductivity of 42.18 and 45.01 W m−1 K−1 in fiber alignment direction, respectively, which were about 209 and 224 times higher than that of PDMS. The excellent thermal conductivity is mainly ascribed that the oriented CF scaffolds construct effective phonon transport pathway in the matrix. In addition, fishbone-shaped CF scaffold was also produced by multiple stacking and carbonization process, and the prepared composites exhibited a controlled heat transfer path, which can allow more versatility in the design of thermal management system.

In Situ Construction of High-Thermal-Conductivity and Negative-Permittivity Epoxy/Carbon Fiber@Carbon Composites with a 3D Network by High-Temperature Chemical Vapor Deposition

“…Carbon fiber (CF), as a low-density, high-strength, high-modulus-ratio fibrous material, has good properties such as abrasion resistance, heat resistance, dimensional stability, and chemical resistance. , Currently, carbon fiber has become a reinforcing material with great development potential and broad application prospects. − However, the surface inertness of carbon fiber leads to interfacial effects with the polymer, which affects the thermal and mechanical properties of the composite materials. , The use of surface modification technology can improve the surface activity of carbon fiber, strengthen the interfacial properties between the carbon fiber and the matrix, and improve the bonding effect between the carbon fiber and the matrix, thus increasing the value of carbon fiber materials in industrial applications. Torokhov and others proposed thermal oxidation to surface-modify carbon fibers in order to enhance the interfacial interaction between carbon fibers and the polymer matrix.…”