Surface modification of BNNS bridged by graphene oxide and Ag nanoparticles: A strategy to get balance between thermal conductivity and mechanical property

Thermal conductive polymeric composites are becoming more and more important in the rapid development of new generation electronic equipment, which can quickly dissipate the heat generated by the equipment to ensure their stable operation with high reliability. Nowadays, the most effective way to prepare thermal conductive polymeric composites is to incorporate efficient thermal conductive fillers into polymers. However, the large thermal resistance at interfaces and degradation of mechanical properties arising from the large filler content restrict their practical applications. Herein, surface modification of BNNS by polydopamine (PDA) was carried out to improve the interfacial compatibility and interaction between fillers and polymer matrix , a simple doctor blading method was adopted to prepare PVA composite films with an aligned structure. In addition, the decoration of silver nanoparticles on BNNS surface and the addition of small amount of GO can help to promote the continuity and reduce the defect of the filler skeleton. Thus, an increase in thermal conductivity (in-plane: 6.54 W m −1  K −1 , through-plane: 1.03 W m −1  K −1 ) was observed in PVA/BNNS-PDA-Ag (10 wt%)/GO (0.5 wt%) composite film, which also possessed excellent flexibility and a favorable mechanical property of 97.1 ± 5.1 MPa.