The microcapsules containing wax encapsulated by poly(methyl methacrylate-co-acrylic acid) (P(MMA-co-AA)) with diameter in the range of 1～5 μm were fabricated by radical polymerization around the wax in a dispersion system.The chemical structure

morphology and thermal behavior of the microcapsules were studied by FTIR

phase-contrast optical microscope

SEM and thermal analysis.The thermal properties of the microcapsules revealed that the content of the core material was up to about 70%

and the microcapsules had a high latent heat (ca. 99 J/g).The dispersed microcapsules can be used as a latent functional thermal fluid to improve the heat transfer efficiency in the fields of refrigeration and air-conditioning.