Studies on rheological properties and isobaric heat capacity of ZnO - [C4mim][BF4] nanoparticle enhanced ionic liquid

Abstract

Nanotechnology is evolving every year and contributes significantly to energy savings in many heat exchange operations. This article provides some experimental insights into the area of ionic liquids and nanoparticle enhanced ionic liquids, while the tests were performed with [C4mim][BF4] and ZnO nanoparticles in mass concentrations up to 2.5 %wt.. Data were collected at different temperatures and successive heating – cooling cycles were applied to check the properties hysteresis as well as the new fluids behavior as heat transfer agents. Results indicated a normal fluidic behavior, while the increase in viscosity is moderate, as well as the decrease in isobaric heat capacity. A special behavior was noticed for the sample with 2.5 %wt. ZnO, that has non Newtonian flow and the isobaric heat capacity was higher than that of the low concentration suspensions. Further, results were discussed in terms of phenomenon and current knowledge and few correlations were proposed. Concluding, even if this research is a step forward to nanoparticle enhanced liquids state of the art, there is still enough room for research in order to get a full understanding of these fluids comportment at heat transfer.