Fabrication and applications of dual-responsive microencapsulated phase change material with enhanced solar energy-storage and solar photocatalytic effectiveness

In this study, a novel type of dual-responsive microencapsulated phase change material (PCM) was fabricated by encapsulating n-eicosane into a brookite TiO2 shell through emulsion-templated interfacial polycondensation, followed by impregnation of ZnO. The resulting microcapsules are expected not only to generate a thermal response by phase transitions of the PCM core but also to gain a photocatalytic response capability originated from the ZnO-doped TiO2 shell. The dual-responsive microcapsules were found to show a perfect core-shell microstructure as well as a regular morphology, and their chemical compositions and microstructure were determined by various spectroscopy and microscopy characterizations. The thermally responsive behaviors and phase change performance of the dual-responsive microcapsules were confirmed by differential scanning calorimetry and their photocatalytic response was identified by an antibacterial experiment. An applied research was carried out by incorporation of the dual-responsive microcapsules into the gypsum matrix, and the resulting gypsum/microcapsule composites not only presented a diverse range of superior thermal performance including prominent thermal regulation and thermal management capabilities, high thermal reliability, good operation durability and highly stable shape/form, but also showed an enhanced antibacterial function. This type of dual-responsive microcapsules exhibits a great potential for solar thermal energy-storage, energy-saving, healthcare and medical applications.