Nanofluids based on fluorinated graphene oxide for efficient thermal management

Nanofluids containing various concentrations of graphene oxide (GO), fluorinated graphene oxide (FGO) and highly fluorinated graphene oxide (HFGO) were prepared and their thermal conductivity (TC) was evaluated at different temperatures. Here we report the enhanced TC of stable suspensions of FGO (fluorine (F) ∼5.6%) and HFGO (F ∼ 23%) in comparison to benchmark GO and bare carrier fluids. Enhancement in TC of up to 15-25% is observed in these fluorinated suspensions even at lower filler fractions of 0.01-0.10 wt% and all fluids exhibit filler dependent enhancement in TC. The enhanced TC observed in the case of FGO and HFGO is explained based on liquid layering and percolation mechanism. Moreover, this investigation also unveils the role of F ^- in enhancing the TC of GO by modifying the surface properties and the effect of liquid layering in determining effective TC of nanofluids.