Fabrication and characterization of conductive microcapsule containing phase change material

Abstract

Microencapsulated phase change materials (MicroPCMs) were fabricated using n-octadecane as PCM and melamine-formaldehyde as shell via in situ polymerization. They were coated with polypyrrole (PPy) to fabricate conductive microcapsules. The structure, morphology, thermal properties and the electrical conductivity of the microcapsules were characterized using the scanning electron microscope (SEM), the Fourier transformed infrared spectroscopy (FTIR), the thermo gravimetric analysis (TGA), the differential scanning calorimetry (DSC) and the standard four-probe method. The results show that, n-octadecane is well encapsulated in rough and compact spherical composites. The melting and freezing the composites latent heats are 90.2 and 92.0 J/g, respectively, while the mass percentage of the n-octadecane in the composites is 49.7%. The melting and crystallizing peak temperature of PPy/MicroPCMs is 24.6°C and 17.9°C, respectively. The addition of PPy improves the thermal stability of the composites. The conductivity of the PPy/MicroPCMs increases from 0.1 S·cm-1 to 0.33 S·cm-1 as the PPy concentration increases from 3 to 10 wt%.