  Polymer composites with thermally conductive nanoscale filler particles, such
as graphene and hexagonal boron nitride (h-BN), are promising for certain heat
transfer applications. While graphene-polymer composites have been extensively
investigated, studies on h-BN-polymer composites has been relatively rare. In
this paper, we use molecular dynamics (MD) simulations to study the interfacial
thermal conductance (ITC) involved in the h-BN-polymer composites. We first
compare the ITC across h-BN/hexane (C6H14) interfaces to that of
graphene/hexane interfaces, where we found that the electrostatic interaction
due to the partial charge on h-BN atoms can play an important role in such
interfacial thermal transport. Based this finding, we further explore the
thermal transport across different h-BN interfaces, including h-BN/hexanamine
(C6H13NH2), h-BN/hexanol (C6H13OH), h-BN/hexanoic acid (C5H11COOH), where the
increasingly polar molecules lead to systematic changes in the electrostatic
interactions between h-BN and polymers. Heat flux decomposition and atom number
density calculations are performed to understand the role of electrostatic
interaction in thermal transport across h-BN-polymer interfaces. It was
observed that stronger electrostatic interactions across the interfaces can
help attract the polymer molecules closer to h-BN, and the reduced interface
distance leads to larger heat flux contributed from both van der Waals and
electrostatic forces. These results may provide useful information to guide the
design of thermally conductive h-BN-polymer nanocomposites.
