Effect of core-shell ratio on the thermal energy storage capacity of SiO2 encapsulated lauric acid

Abstract

Lauric acid (LA), an eco-friendly fatty acid, is used as phase change materials (PCMs) and tetraethyl orthosilicate (TEOS) as the precursor solution of SiO2 for sol-gel process. In the present study, various core-shell ratios are taken for the microencapsulation of LA with SiO2. The effect of different core-shell ratios on the chemical, structural, and thermal properties are studied by different techniques such as Fourier transform-infrared spectroscope (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). FT-IR, XRD, XPS, SEM, and TEM results confirmed the proper microencapsulation of LA with SiO2 shell while DSC and TGA revealed about excellent thermal stability of the microencapsulated LA. Core-shell ratios played a vital role on the microencapsulation of LA with SiO2 which affected the overall performance and structure of the encapsulated PCMs. PCMs with the highest core-shell ratio i.e., LATEOS6, exhibited the highest encapsulation ratio (92.39%), encapsulation efficiency (93.48%) as well as excellent thermal reliability even after 30 cycles of heating and cooling. These results suggested that microencapsulated LA would be a promising material for thermal energy storage as well as construction building materials (CBMs) to solve mass concrete problems.