Possessing the fluxility of transfer fluids and the latent heat capacity of PCMs (phase change materials), fatty acids PCSs (phase change slurries) can be utilized as a superior alternative to store thermal energy collected from many fields. CA (Capric acid)-LA (lauric acid) PCSs, with span20/SDS used as emulsifiers in the mass ratio of 3.24:1, are prepared for the first time in this paper. The optimized parameters, including the concentration of fatty acids, shearing rate and shearing time, are investigated during the preparation based on the criteria of the average droplet size. The morphology, rheological behavior of obtained PCSs are also further elaborated, as well as thermophysical properties. The results indicate that obtained PCSs in the form of milky liquid occupy the average droplet size of 1 mu m. Supercooling is alleviated from 20 degrees C to 10 degrees C by the introduction to hexadecanol. And the latent heat of PCSs with 30 wt % and 50 wt% fatty acids is 43.36 and 74.43 J/g, respectively. Additionally, fatty acids PCSs show excellent stability in the point view of the droplet size, viscosity and thermophysical properties under the conditions of storage and 100 freezing/melting cycles. (C) 2015 Elsevier Ltd. All rights reserved.