Research on enhancing thermal conductivity of phase change microcapsules with nano-copper

Abstract The unique ability of phase change materials (PCMs) to store and release heat makes their integration into building materials promising for reducing energy consumption and enhancing sustainability. In this work, a novel high-thermal-conductivity microencapsulated phase change material was studied, with nano-copper embedded in the microcapsule structure. This modification enhanced thermal conductivity while largely preserving the material’s latent heat storage capacity. Poly(ethyl acrylate) (PEA) is chosen as the capsule shell, whereas a eutectic mixture of decanoic acid (CA) and lauric acid (LA) serves as the core material. The analysis results indicate that as the shell-core mass ratio decreases, the microcapsule size increases, and both thermal conductivity and thermal diffusivity gradually decrease. Moreover, the latent heat capacity of microencapsulated phase change material (MEPCM) increases. When the shell-core mass ratio is 1:1.5, the melting latent heat and solidification latent heat are 81.85 J g −1 and 88.68 J g −1 , respectively. nano-copper doping enhances the material’s thermal conductivity and thermal diffusivity by 47.5% and 50%, respectively, leading to a 20.3% improvement in heat storage efficiency. After 200 cycles of testing, the material maintains good thermal reliability and chemical stability. Mortar-based composite materials containing microcapsules were prepared. The mortar composite materials containing microcapsules exhibited minimal influence from heating and cooling, with those containing nano-copper microcapsules demonstrating superior thermal response speeds. The method of doping and modifying MEPCM with nano-copper is a promising approach for effectively reducing the impact of temperature fluctuations on the internal comfort of buildings, improving energy utilization efficiency, and providing reliable solutions for temperature-sensitive applications.