The rapidly increasing device densities
in electronics dictate
the need for efficient thermal management. If successfully exploited,
graphene, which possesses extraordinary thermal properties, can be
commercially utilized in polymer composites with ultrahigh thermal
conductivity (TC). The total potential of graphene to enhance TC,
however, is restricted by the large interfacial thermal resistance
between the polymer mediated graphene boundaries. We report a facile
and scalable dispersion of commercially available graphene nanoplatelets
(GnPs) in a polymer matrix, which formed composite with an ultrahigh
TC of 12.4 W/m K (vs 0.2 W/m K for neat polymer). This ultrahigh TC
was achieved by applying high compression forces during the dispersion
that resulted in the closure of gaps between adjacent GnPs with large
lateral dimensions and low defect densities. We also found strong
evidence for the existence of a thermal percolation threshold. Finally,
the addition of electrically insulating boron-nitride nanoparticles
to the thermally conductive GnP-polymer composite significantly reduces
its electrical conductivity (to avoid short circuit) and synergistically
increases the TC. The efficient dispersion of commercially available
GnPs in polymer matrix provides the ideal framework for substantial
progress toward the large-scale production and commercialization of
GnP-based thermally conductive composites.
Thermal management has become a critical aspect in next-generation miniaturized electronic devices. Efficient heat dissipation reduces their operating temperatures and insures optimal performance, service life, and efficacy. Shielding against shocks, vibrations, and moisture is also imperative when the electronic circuits are located outdoors. Potting (or encapsulating) them in polymer-based composites with enhanced thermal conductivity (TC) may provide a solution for both thermal management and shielding challenges. In the current study, graphene is employed as a filler to fabricate composites with isotropic ultrahigh TC (>12 W m(-1) K(-1)) and good mechanical properties (>30 MPa flexural and compressive strength). To avoid short-circuiting the electronic assemblies, a dispersion of secondary ceramic-based filler reduces the electrical conductivity and synergistically enhances the TC of composites. When utilized as potting materials, these novel hybrid composites effectively dissipate the heat from electronic devices; their operating temperatures decrease from 110 to 37 °C, and their effective thermal resistances are drastically reduced, by up to 90%. The simple filler dispersion method and the precise manipulation of the composite transport properties via hybrid filling offer a universal approach to the large-scale production of novel materials for thermal management and other applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.