Effect of graphene nanoplatelet concentration on the thermal conductivity of silicone thermal grease

We herein report a facile route to improve the thermal conductivity of silicone thermal grease without deteriorating its conformability via exploitation of outstanding thermal conductivity and mechanical flexibility/ ductility of graphene materials. The silicone thermal greases containing GNPs were prepared by using the high-energy ball milling process. The SEM images proved that GNPs were well dispersed in the base grease. The thermal conductivity of the thermal greases was investigated and presented. The obtained results demonstrated that GNPs are efficient for the thermal conductivity enhancement of the thermal grease. The highest thermal conductivity enhancement up to 59 % was obtained with the grease containing 0.75 vol. % GNPs. The enhancement could be attributed to high thermal conductivity of GNPs, the good compatibility and uniform dispersion of GNPs in the thermal grease. The thermal conductivity of the thermal grease with higher GNPs concentration of 1 vol. % was decreased due to the formation of GNPs clusters. By using Chu's model with the interfacial thermal resistance (R_k) fitting, we found that the thermal conductivity enhancement of the thermal grease concerns to the R_k between GNPs and the grease matrix. The best way to improve the thermal conductivity of the thermal grease is to reduce the R_k. The obtained results demonstrated the advantages of GNP in the thermal greases for the heat dissipation in high power electronic devices.