The synthesis and characterization of phase change material microcapsules with surface-modified titanium oxide nanotubes for thermal energy regulation

To address energy supply constraints and improve energy use efficiency, phase change materials (PCMs) have been introduced as a thermal storage solution. Given that building energy consumption constitutes a significant portion of society’s total energy usage, there is a substantial opportunity for energy conservation within the building sector. The strategic application of PCMs can help save energy and significantly reduce carbon dioxide emissions by harnessing external thermal energy in a rational manner. Microencapsulation of PCMs effectively prevents leakage while shielding them from environmental degradation factors. thus extending their lifetime. This study addressed the limitations of organic shell materials in PCMs, particularly their low thermal conductivity and flammability, by incorporating titanium oxide nanotubes (TNTs), which have a large specific surface area. Surface-functionalized TNTs, denoted as Si-TNTs, are synthesized via grafting with (3-aminopropyl)triethoxysilane (APTES). This surface modification significantly improves their dispersion stability and flame retardant efficiency, attributed to the introduction of amino groups and enhanced interfacial interactions. The integration of Si-TNTs into phase change materials microcapsule (MPCM) results in epoxy coatings with enhanced temperature regulation. Specifically, the temperature regulation performance is significantly improved, with a temperature reduction of 11.2 °C compared to pure epoxy resin. Additionally, the modified epoxy coatings exhibit a 12.6 % reduction in heat release rate (HRR) and improved hydrophobicity, with a high water contact angle of 94.84°. These properties make them promising for building energy efficiency and thermal management applications.