Vitrimeric silicone composite with high thermal conductivity and high repairing efficiency as thermal interface materials.

Thermally conductive composites with self-healing ability can not only solve the heat dissipation problem of integrated electronic devices but also help improve their service life, thereby reducing electronic waste. In this study, a self-repairing thermally conductive composite with good electrical insulation, high thermal conductivity, high healing efficiency, and excellent mechanical strength was designed and prepared using a silicon vitrimer as the matrix and functionalized boron nitride nanosheets (fBNNS) as the thermally conductive filler. The tensile strength of the vitrimers with 10 wt% of octaglycidyl polyhedral oligomeric silsesquioxane (POSS) increased by 2.82 times to 8.4 ± 0.1 MPa with respect to that without POSS. In addition, the composites exhibited excellent thermal conductivity of 1.41 ± 0.05 W/mK with 66 wt% of fBNNS, which is more than 6 times higher than that of undoped elastomers. More importantly, the repair efficiency of undoped vitrimeric silicone can be as high as 98.8 ± 1.1%, which was slightly reduced to over 92.0% by adding 66 wt% of fBNNS. Further, it could recover 99.3% of the thermal conductivity even after 6 healing cycles. The self-healing thermally conductive composites exhibited excellent wettability and good adhesion to different wafers and substrates, demonstrating excellent performance as thermal interface materials for high-power electronic devices.