High performance thermal conduction of silver microparticles thermos-compressed in three-dimensionally interconnected polystyrene beads

We demonstrate a facile strategy to prepare polymer composite with anomalously increased thermal conductivity based on Ag network and structured polymer matrix. Conventional thermal compression process combined with colloidal type thermoplastic beads as structural matrix enabled efficient interconnected thermal conduction pathways of Ag microparticles, giving rise to extremely high thermal conductivity of 120 W/mK at 70 vol% of Ag particles comparable with one third of the value of pure Ag. The systematic investigation with different types of polymer matrix, such as thermoset epoxy and cross-linked colloidal bead, suggests that appropriate frictional force exerted on Ag particles with polymer matrix during compression is of prime importance for developing Ag conduction pathways. Furthermore, the thermoplastic PS beads matrix also provides sufficient mechanical strength to preserve the networked Ag pathways with firm interfaces.