Surface construction of Ni(OH)2 nanoflowers on phase-change microcapsules for enhancement of heat transfer and thermal response

Abstract

A phase-change microcapsule system based on an n-docosane core and SiO2/nanostructural Ni(OH)2 layer-by-layer shell was designed with the aim to enhance the heat transfer and thermal response capability of phase-change microcapsules. This system was fabricated through emulsion-templated interfacial polycondensation to form a SiO2/n-docosane microcapsule system, followed by anchoring Ni(OH)2 nanoflowers on the surface of the SiO2 shell via structure-directed interfacial precipitation. The resultant microcapsule system achieved a satisfactory latent heat-storage capacity of around 130 J/g with high energy-storage efficiency over 99%. Compared to conventional SiO2/n-docosane phase-change microcapsules, this microcapsule system not only presents high thermal conductivity, rapid heat transfer rate, good leakage prevention capability, high heat charging-discharging stability, but also exhibits a good phase-change reversibility and resilience ability to perform repetitious solid-liquid phase transformations. The combination of traditional phase-change microcapsules with a nanostructural Ni(OH)2 outer layer results in a significant enhancement in heat transfer, which makes the system a fast thermal response ability to satisfy a variety of applications where fast and stable thermal energy storage/release is required. Through constructing the Ni(OH)2 nanoflowers on the surface of conventional phase-change microcapsules, this study offers a promising strategy for the design and fabrication of high-performance phase-change microcapsules with fast thermal response.