Fabrication and Performance Characterization of Highly Stable Multifunctional Phase Change Microcapsules Based on CuWO ₄ –EC Double-Shell Heterointerfaces

The microencapsulated phase change materials (MePCMs) are widely applied in energy storage and thermal management systems. Nevertheless, conventional single-shell microcapsules still suffer from insufficient thermal stability, phase change material (PCM) leakage, and limited functional integration. In order to address these issues, this study develops multifunctional paraffin@copper tungstate-ethyl cellulose (PW@CuWO 4 -EC) microcapsules featuring an inorganic–organic double-shell by a two-step encapsulation method. The experimental results indicate that the double-layer structure of the CuWO 4 inner shell and EC outer shell can stably encapsulate PW, forming spherical microcapsules with good structural integrity and dispersibility. When the dosage of EC was 1/30 of the PW mass, the phase change enthalpy and encapsulation efficiency of the PW@CuWO 4 -EC sample reached as high as 85.12[Formula: see text]J/g and 69.38%, respectively. Compared with microcapsules with only a single-layer CuWO 4 shell, the secondary coating of the EC shell increased the onset decomposition temperature by about 50[Formula: see text]C and effectively prevented leakage at 100[Formula: see text]C. Furthermore, the CuWO 4 -EC heterointerface made the separation of photogenerated carriers more efficient, leading to microcapsules exhibiting strong UV absorption and obvious fluorescence quenching characteristics. The material design and construction of highly stable, multifunctional double-shell MePCMs can be based on the ideas and principles provided by this study.