Supercooling suppression of microencapsulated phase change materials (mPCMs) with melamine formaldehyde shell by adding nucleating agent into the core material prior to encapsulation

In the field of thermal energy storage, phase change materials (PCMs) are receiving more and more attention to utilize renewable energy resources. Under the influence of microencapsulation, PCMs experience an undesirable phenomenon called supercooling which is solidification at a temperature below the phase transition temperature and thus their widespread application would be limited. In this paper, n-hexadecane (HD) microcapsules with melamine formaldehyde shell were synthesized by in situ dispersion polymerization. Octadecane and paraffin were used as nucleating agents in order to suppress supercooling. Fourier transformed infrared spectroscopy (FT-IR) confirmed the successful encapsulation. Obtained images from scanning electron microscopy (SEM) showed spherical shapes with smooth surfaces for prepared microcapsules containing paraffin as nucleating agent. Based on differential scanning calorimetry (DSC) thermograms, paraffin was a more efficient nucleating agent than octadecane and reduced supercooling to 1 ˚C. Thermal gravimetric analysis (TGA) thermograms represented high thermal stability at elevated temperatures.