Investigation of thermal and electrical conductivity of graphene based nanofluids

We report for the first time, the synthesis of highly stable exfoliated graphene based nanofluids with water and ethylene glycol as base fluids with out any surfactant and the subsequent studies on their thermal and electrical conductivities. Graphene was synthesized by thermal exfoliation of graphene oxide at 1050 degrees C in Ar atmosphere. The as-synthesized graphene has been suitably functionalized and further dispersed it in the base fluids without any surfactant. Thermal and electrical conductivities of these nanofluids were measured for varying volume fractions and at different temperatures. An enhancement in thermal conductivity by about 14% has been achieved at 25 degrees C with deionized water (DI) as base fluid at a very low volume fraction of 0.056% which increases to about 64% at 50 degrees C. Electrical conductivity measurements for these nanofluids indicate an enormous enhancement at 25 degrees C for a volume fraction of 0.03% in DI water. (C) 2010 American Institute of Physics. [doi:10.1063/1.3516289]