Effects of Hydrophobized Fumed Silica Particles on the Rheological and Thermal Properties of Oil-in-Oil Phase Change Material Emulsions

Phase change material emulsions are used as thermal energy storage media. They consist of phase change material dispersed in droplet form within an immiscible heat transfer fluid, stabilized by an emulsifying agent. The addition of nanoparticles is a novel approach to stabilizing these emulsions. In this investigation, oil-in-oil Pickering emulsions were formulated, using paraffin as the dispersed phase and polyethylene glycol 400 as the continuous phase. Stabilization was achieved through the use of hydrophobized pyrogenic silica nanoparticles. The study examined the effect of different stabilizer concentrations on emulsion morphology, rheology, and thermal properties. The results demonstrate effective stabilization by nanoparticles, leading to gel-like structures, improved rheological properties, and minimal thermal impact.