Microcapsules loaded with sodium phosphate dodecahydrate (DSP) were prepared according to the solvent evaporation method. The microencapsulated phase-change materials (MEPCMs) possessed methyl methacrylate crosslinked with ethyl acrylate generated poly(methyl methacrylate) (PMMA) as the coating polymer. The influences of the polymerization time, polymerization temperature, and organic solvent types on the performances of the MEPCMs were studied in this report. The results indicate that the polymerization time and temperature had barely any effect on the size but a significant effect on the surface morphology of the microphase-change materials. The solubility of the shell material varied in different organic solvents, and this to different phase-transition enthalpies. In addition, DSP could be encapsulated well by PMMA, and the as-prepared MEPCMs were equipped with a good morphology and a small particle size. When toluene and acetone were used as organic solvents, the MEPCMs had an interesting energy storage capacity of 142.9 J/g at 51.51 degrees C, and this made them suitable for different applications. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1516-1523, 2013