Development of BaSO4@n-eicosane phase-change microcapsules with high corrosion resistance for thermal regulation application in architectural coatings

Microencapsulated phase change materials (PCMs) are a promising candidate to provide huge opportunities for energy-saving buildings; however, the most usually used shell materials for encapsulation of PCMs, such as CaCO3 and SiO2, have poor corrosion resistance, resulting in a limitation in their practical applications in the architectural field. Focusing on an effective solution to this issue, we have developed a new type of microencapsulated PCM with n-eicosane as a core and BaSO4 as an inorganic shell through emulsion-templated controllable precipitation. The resultant BaSO4@n-eicosane microcapsules exhibit an ellipsoidal morphology and a well-defined core-shell microstructure, together with a satisfactory latent heat capacity of over 100 J/g. The BaSO4 shell contributes high thermal conduction, rapid heat transfer, high acid and alkali resistance, and outstanding thermal cycling stability to the fabricated microcapsules. This can meet the requirement of long-term use in thermal self-regulatory architectural coatings. The developed composite coatings containing the BaSO4@n-eicosane microcapsules exhibit efficient temperature regulation performance along with high hardness, good scratch resistance, and high corrosion resistance. Based on an investigation into the practical application of the composite coatings, the developed composite coatings can be used for the house roof coating to reduce the indoor temperature effectively, indicating good application potential for comfort temperature regulation in energy-saving buildings. This study offers a new approach to develop multifunctional architectural coatings for sustainability.