BaSO4-encapsulated multifunctional phase change material with enhanced thermal storage and radiation shielding for building applications

Microencapsulated phase change materials (MPCMs) are increasingly utilized in energy-efficient building systems, primarily aimed at improving indoor thermal comfort while also reducing overall energy demands. To further extend the range of MPCM applications, recent research efforts have been directed towards the development of MPCMs with enhanced multifunctional capabilities that go beyond traditional thermal energy storage. In this study, a novel multifunctional MPCM, termed Oc/Ei@BaSO 4 , was synthesized using a self-assembly technique. The core consists of a 7:3 blend of octadecane and eicosane, encapsulated within a barium sulfate shell. The high atomic number of Ba provides Oc/Ei@BaSO 4 with enhanced ionizing radiation shielding capabilities. The binary core composition provides dual phase change temperatures of 9.0 °C and 27.6 °C, making it suitable for thermal storage across multiple seasons. After 100 thermal cycles, the latent heat of Oc/Ei@BaSO 4 decreased by only 1.59 J/g, meeting the requirements for good thermal stability in building wall applications. Additionally, cement blocks incorporating various mass fractions of Oc/Ei@BaSO 4 (CPM) were prepared, and their ionizing radiation shielding performance was characterized through both experimental measurements and simulations. The results indicate that the inclusion of Oc/Ei@BaSO 4 significantly improved the shielding capacity of CPM across different X-ray intensities, with the linear attenuation coefficient of CPM 8 % increasing by 27.62 % compared to the control group. The relationship between Oc/Ei@BaSO 4 content and the attenuation coefficient of CPM was further predicted using the XCOM code, showing good predictive accuracy, especially at lower radiation intensities, with deviations from experimental values of around 20 %. The development of this multifunctional MPCM extends the applicability of MPCMs, offering potential for radiation shielding in medical facilities, nuclear power plants, and space radiation protection, providing a promising solution for these specialized areas within the construction industry.