Enhanced Thermal Conductivity of Phase Change Microcapsules Based on Boron Nitride/Graphene Oxide Composite Sheets

Large energy storage capacity and high heat conduction are very important for phase change materials. Phase change microcapsules (PCMCs) were synthesized through in situ polymerization by using paraffin as the core material. The melamine–formaldehyde (MF) polymer shell of PCMCs was modified with boron nitride/graphene oxide composite sheets (BN/GO CSs) to improve thermal conduction. The preparation condition of BN/GO CSs through the self-assembly process and the synthesis process of composite PCMCs (CPCMCs) in the presence of BN/GO CSs were systematically investigated. The thermal conductivity of CPCMCs synthesized under the optimized condition significantly increased about 190% relative to the incorporated paraffin. Promisingly, the introduction of BN/GO CSs hardly influenced the encapsulation process, allowing high encapsulation rate (>93%) and high phase change enthalpy (∼200 J·g–1). This work is an enlightening complementarity to the very limited research attempts that incorporating multiple fillers in PCMCs. We postulated and proved the synergistic effect of BN/GO CSs and their advantages in improving the thermal conductivity of the resultant PCMCs without scarifying the essential heat storage capacity. We envision that the insights and the CPCMCs synthesized can be applied in a range of material designs for energy and electronic applications.