Interfacial thermal conductance-rheology nexus in metal-contacted nanocomposites

Tailoring high interfacial thermal conductance is crucial for many applications and is often challenging even for interfaces comprised of high thermal conductivity materials. Here, we report the correlation between the rheological behavior of a gold-nanowire-filled polydimethylsiloxane nanocomposite and its interface thermal conductance with copper. At a critical filler fraction, an abrupt increase in the nanocomposite thermal conductivity is accompanied by a liquid-solid transition and a multifold decrease in interface conductance. These concurrent changes are attributed to nanowire percolation network formation and pre-cure polymer gelation that inhibits the formation of conformal void-free interfaces. These findings will be important for designing processing sequences to realize high thermal conductance interfaces. © 2013 AIP Publishing LLC.