Perfluoroalkylsilane-Modified Boron Nitride Nanosheets for Epoxy Composites with Improved Thermal Conductivity and Dielectric Performance

The development of polymer-based packaging materials with excellent heat dissipation capacities and low dielectric constants is increasingly desired for the modern microelectronic industry. Herein, boron nitride nanosheets (BNNSs) were coated with polydopamine (PDA) and subsequently grafted with tridecafluorooctyl trimethoxy silane. Compared with unmodified BNNSs, as-prepared perfluoroalkylsilane-modified BNNSs (PFOS-BNNSs) show distinctly improved miscibility in the epoxy matrix. Consequently, the epoxy/PFOS-BNNSs (30 wt %) composite shows a higher thermal conductivity of 1.15 W m–1 K–1, which increases by 538 and 42% when compared to the neat epoxy and the epoxy/BNNSs composite, respectively. Notably, the ultralow molar polarizability of C–F bonds enables the epoxy/PFOS-BNNSs composite to have lower dielectric constant and dielectric loss tangent than those of the epoxy/BNNSs composite. Finally, the impacts of the surface modification of BNNSs on the rheological, thermal, and mechanical properties of the resulting epoxy composites were also investigated in detail.