The exfoliation and functionalization of boron nitride nanosheets and their utilization in silicone composites with improved thermal conductivity

An efficient method is reported to fabricate boron nitride nanosheets (BNNSs) using a sonication technique in mixed solvents, and functionalization of BNNSs is performed by polydopamine (PDA). The BNNSs showed good dispersibility in mixture solvent. And the functionalization of BNNSs by PDA (named as BNNSs@PDA), can further improve its stability in water. The morphologies of the BNNSs and BNNSs@PDA were characterized by AFM, SEM, and TEM, which confirm the successful exfoliation and functionalization of BNNSs. Furthermore, silicone composites were fabricated by adding BNNSs and BNNSs@PDA, respectively. Compared with neat silicone (0.20 W m−1K−1), the thermal conductivity of silicone composite with 12 wt% BNNSs@PDA increases highly by 90% to 0.38 W m−1K−1. The thermal stability of silicone/BNNSs@PDA composite is also improved. The significantly improved thermal conductivity and thermal stability are attributed to the good dispersion of BNNSs@PDA and stronger interaction between BNNSs@PDA surface and silicone matrix.