Synthesis of nano-size paraffin/silica-based encapsulated phase change materials of high encapsulation ratio via sol–gel method

Paraffin and Silica (SiO2)-based encapsulated phase change materials (ePCMs) were synthesized to enhance thermal and phase change performance. Nano-encapsulation of paraffin by SiO2 shell was accomplished via the sol–gel method using the triethoxymethylsilane precursor. Fifteen different samples of ePCMs were synthesized and analyzed for their varied core/shell mass ratio and thermal properties. Additionally, these ePCMs were characterized using X-Ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX), and dynamic light scattering (DLS). The synthesis procedures were verified to properly encapsulate paraffin inside the silica shell with varying degrees of reaction efficacy as documented in this work. The maximum effective latent heat of melting and solidification for the ePCMs was got to be 115.07 J/g and 114.19 J/g. The best-performing sample reached an encapsulation ratio of 81.8% which also successfully completed shell leakage testing after melting/freezing cycles. Latent heat and temperature values remained unaffected after 100 melting/freezing cycles confirmed by differential scanning calorimetry (DSC).