Modeling the effective thermal conductivity and viscosity of pickering emulsions

Pickering emulsions, consisting of two immiscible liquids stabilized by solid particles, are of great interest and have a wide range of applications due to their advantages over conventional emulsions. The main ones are high stability, low toxicity, controllable rheological properties, and ease of preparation. Pickering phase change material emulsions, as a type of heat storage media, have high energy capacity, good fluidity, and excellent heat transfer performance. In this work, taking into account the microstructure and using effective medium theory a new thermal conductivity model of Pickering emulsions is proposed. The Pickering emulsion structure is presented as a periodic structure in which solid nanoparticles in the continuous phase form a shell around a spherical droplet of the dispersed phase. The predictions of the proposed models were compared with the available experimental data and the results of the Maxwell model, and a good correlation was achieved for both Pickering and conventional emulsions. To estimate the relative viscosity of Pickering emulsions, a new viscosity model developed for aqueous electrolyte solutions was used. {Graphical Abstract}