Next-generation electronic packaging materials: thermal-dielectric properties and design strategies in PI and PTFE-based composites

Abstract The rapid advancement of high-frequency and high-power electronic technologies has created an urgent demand for materials that simultaneously exhibit high thermal conductivity, low dielectric constant and loss, and robust mechanical reliability. Polyimide (PI) and polytetrafluoroethylene (PTFE) are among the most promising polymer matrices for advanced electronic packaging owing to their outstanding thermal stability, chemical resistance, and electrical insulation properties. Nevertheless, the relatively high dielectric constant of PI and the poor interfacial adhesion of PTFE and their intrinsically low thermal conductivity significantly limit their direct application in next-generation electronic substrates. This review systematically summarizes recent progress in PI and PTFE-based composite systems, with a particular focus on design strategies, fabrication routes, and structure property relationships governing their multifunctional performance. Various processing techniques are critically evaluated with respect to interfacial engineering, dispersion of fillers, and construction of networks. Emphasis is placed on ceramic, carbon, metal oxide and metallic fillers that enable the formation of efficient thermally conductive yet electrically insulating pathways within PI and PTFE matrices. Furthermore, the roles of surface functionalization, coupling agents, and hierarchical or double-percolation architectures in enhancing phonon transport, suppressing dielectric loss, and improving mechanical integrity are discussed in detail. Finally, current challenges and future perspectives are outlined, including interface optimization, filler alignment control, low-loss dielectric tailoring, and scalable manufacturing strategies for high-frequency applications such as 5G and microwave electronics. This review provides a comprehensive understanding of processing-structure-property correlations in PI-based and PTFE-based composites and offers guidance for the rational design of high-performance polymer composites for advanced electronic packaging materials. Graphical abstract