New multilayered microencapsulated phase change material with CaCO3 and Ag shells

Phase change materials (PCM) are microencapsulated to make them easier to handle and compatible with environments they are used in. Thermal conductivity of PCMs, which is already low for organics, decreases further due to the polymer based shells used in the process. In this study, n-heptadecane as PCM was coated with natural based material CaCO3 and Ag in order to improve thermal conductivity. Low-cost and facile self-assembly method was preferred in synthesis of microencapsulated PCMs (mPCM). Differential scanning calorimetry (DSC) analysis of the synthesized microcapsules shows that n-heptadecan@CaCO3 microcapsule, melting-freezing enthalpies and temperatures were 59.82J/g and 66.04J/g, 26.63 degrees C and 18.68 degrees C, respectively. Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD) results of n-heptadecane@CaCO3 and n-heptadecane@CaCO3@Ag microcapsules confirmed the accomplished encapsulation of n-heptadecane with CaCO3 and Ag. These microcapsules presented a good spherical morphology with a well-defined core-shell microstructure. Thermal conductivity of n-heptadecane was increased from 0.178 to 0.706W/mK for n-heptadecane@CaCO3 and further increased to 1.092W/mK for n-heptadecane@CaCO3@Ag.