Flexible h-BN Foam Sheets for Multifunctional Electronic Packaging Materials with Ultrahigh Thermostability

Miniaturization and integration of electronic devices has required for additional functions such as dissipation of emitting heat and thermal stability. However, phase or structural stability of existing electronic packaging materials is limited by viscoelastic behaviors of polymeric materials (i.e. low heat resistance and poor mechanical strength). Herein, we report a simple and efficient approach to prepare flexible and robust hexagonal boron nitride (h-BN) foam sheet, which exhibits low thermal interfacial resistance due to the formation of three-dimensional continuous networks at high h-BN filling fraction (up to ~80 wt.%). Furthermore, it shows a significant enhancement in thermal stability such as flammability and shrinkage at a high temperature. Combination of thermostability and mechanical strength based on the h-BN foam sheets provides novel opportunities for multifunctional thermal conductive materials in coating and films without severely compromising auxiliary characteristics such as mechanical strength and thermal stability.