Potential of Nanoparticle-Enhanced Ionic Liquids (NEILs) as Advanced Heat-Transfer Fluids

An experiment was conducted to demonstrate that nanoparticle-enhanced ILs (NEILs) increase the heat capacity of the ionic liquids (IL) with no adverse side effects to the thermal stability of ILs. 1-Butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mmim][NTf2]) was selected because it is commercially avaliable from a wide range of vendors and has a tolerable viscosity and good thermal stability. Themethyl blocking of the C-2 proton should decrease the chances of a catalytic/carbene-like interaction with the nanoparticles with minimal effect on the viscosity. The addition of the nanoparticles lead to an increase in the density of 10% for the Al 2O3 NEILs but a decrease of about 10% for the carbon black (CB) NEIL. A significant increase, about 40%, in the volumetric heat capacity was observed for the Al2O3 NEILs, but a decrease of about 30% was observed for the CB NEILs. The ILs and NEILs demonstrated a significant improvemment in the thermal stability without volatization.