Fabrication and morphological characterization of microencapsulated phase change materials (MicroPCMs) and macrocapsules containing MicroPCMs for thermal energy storage

A series of MicroPCMs with gelatin-gum arabic shell, polyurethane shell and styrene-based copolymer shell were fabricated via complex coacervation, interfacial polymerization and suspension polymerization, respectively. Furthermore, a novel MicroPCMs with styrene-divinylbenzene copolymer as inner shell and polyurethane as outer shell was investigated, where styrene and divinybenzene were employed both as cosolvent and shell-forming monomers. Macrocapsules containing MicroPCMs with calcium alginate as matrixes were also prepared by piercing-solidifying incuber method. The morphology and structure of these microcapsules and macrocapsules were characterized by scanning electron microscopy (SEM) and optical microscopy (OM). Fourier transform infrared spectroscopy (FTIR) was used to identify the chemical structure of different copolymer shells. The thermal differential scanning calorimetry (DSC) was employed to measure phase change temperature and enthalpy. In addition, the cross-section of MacroPCMs was characterized as well.