3-Dimensional Network Structured Thermal Interface Materials

Abstract

Conductive polymer composites, which constructed upon polymer matrix of polymethyl methacrylate (PMMA) beads and segregated networks of graphene, hexagonal boron nitride (h-BN), and multi-walled carbon nanotube (MWCNTs) were fabricated by a solvent-mixing and a hot-pressing technique. The effective coating of second-phase conducing fillers on the surface of PMMA beads resulted in the 3-dimensional segregated networks of specific conductive pathways along the grain boundaries of polymer matrix. Based on the 3-dimensionally interconnected filler networks, the electrical conductivity and thermal conductivity of polymer composites could be significantly enhanced up to 313 S/m and 6.12 W/mK. In addition, the differences in the size of PMMA polymer beads ranged from 5 to 20 µm in a diameter were found to be one of key factors in determining the percolation threshold of the conductive polymer composites: we could lower the percolation threshold down to 0.0095wt% in the composite prepared with the 20 um diameter PMMA beads.