Polymer-ceramic nanofiber composites for heat dissipation: a comprehensive review of electrospinning and freeze-drying techniques

Abstract Effective heat dissipation is crucial for the optimal performance and safety of electronic devices. Electronic products and energy-efficient home equipment generate more heat during operation and continuous use. Therefore, it is essential to implement efficient heat dissipation methods to prevent problems such as component malfunctions, increased failure rates, and safety hazards. Polymer composites have recently garnered attention due to their unique properties and versatility. These composites achieve improved thermal conductivity by incorporating ceramic nanoparticles, making them suitable for heat dissipation applications. However, challenges arise from the electrical conductivity of ceramic fillers, which can interfere with the performance of precision electronic components. Additionally, the thermal conductivity of ceramic nanoparticles is typically low (less than 10 W/(m·K)), requiring high filler content (above 50 vol.%), which increases the cost and weight of the composite materials. Nanofiber-based heat dissipation sheets, particularly those fabricated through electrospinning, offer a promising alternative. Ceramic nanofibers provide continuous thermal pathways within the polymer matrix, enhancing heat conduction. However, while in-plane thermal conductivity can be significantly improved, the thermal conductivity in the thickness direction remains limited due to the insufficient heat conduction network in this direction. Advanced techniques such as freeze-drying offer promising solutions to this problem, enabling the formation of three-dimensional (3D) interconnected nanofiber networks. These 3D structures demonstrate superior performance over conventional one-dimensional nanofibers. This review provides a comprehensive overview of the synthesis and integration of ceramic nanofibers, including aluminum oxide (Al 2 O 3 ), aluminium nitride (AlN), silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), and beryllium oxide (BeO), into polymer matrices for heat dissipation applications. It discusses the thermal and electrical performance of these materials alongside emerging strategies to optimize thermal conductivity in both in-plane and thickness directions. Furthermore, this review highlights recent advances in freeze-drying techniques for fabricating 3D nanofiber structures and outlines future directions for overcoming the challenges in synthesizing high-performance ceramic nanofibers.