Microcapsules for energy storage and/or heat transfer applications containing phase-change materials (PCMs-including n-pentadecane, n-eicosane and a paraffin wax) were successfully produced by emulsifying the PCMs as small droplets in an aqueous, water-soluble urea-formaldehyde pre-polymer solution substantially free of emulsifier while polymerizing the pre-polymer at the interface by acid-catalyst. The core/shell structured microcapsules were also characterized with size distribution analysis, scanning electron microscopy, FTIR spectrometry and differential scanning calorimetry.
