Thermophysical properties and stability of paraffin microemulsions as latent functionally thermal fluid

Paraffin microemulsions are multifunctional thermal fluid consisting of water as the continuous phase and paraffin as the dispersed phase. They can store or transfer a large amount of thermal energy by using the latent heat capacity of the paraffin during the phase transition as well as the sensible heat capacity of water. In this study, hexadecane O/W microemulsions were emulsified by an ionic surfactant SDS and a co-surfactant butanol. The phase behavior, effective stability, droplet size and thermophysical properties, such as latent heat and dynamic viscosity, were investigated experimentally. The results showed the prepared microemulsion with 30 wt.% hexadecane has expected high heat capacity about 93.4 J/g and low viscosity about 21 mpa·s. The average droplet size is 73 nm. The results indicate that they have potential applications in thermal energy storage and transfer.