Thermally conductive, electrically insulating, and radiative cooling PVDF/BNNS/Al2O3/cordierite nanocomposites

Abstract

For now, the introduction of fillers with highly intrinsic thermal conductivity (TC) into polymers is the most effective way to prepare composites with excellent heat dissipation capability. However, reducing the filler loading without lowering the TC is the most challenging. In this article, patterned electrospinning and hot pressing were employed to prepare thermally conductive and electrically insulating polyvinylidene fluoride (PVDF)-based composites containing 20 wt% boron nitride nanosheets (BNNSs) as the dominant filler and 5 wt% Al2O3 nanopowders as the auxiliary filler. We have proven “1 + 1>2″ in terms of enhancing the TC of composites at nanoscale by the synergistic effect of nanosheet and nanopowder. The results showed that the in-plane TC (8.55 W/(m·K)), volume resistivity (1.56 × 1015 Ω cm), and breakdown strength (406.2 kV/mm) of the composites were improved by 4759.1 %, 649.0 %, and 34.1 % compared with the neat polymer, respectively. Furthermore, the potential application of such composites in contact heat dissipation and radiative cooling was demonstrated by the experiment of integrating cordierite particles with high infrared radiation onto the films.