Constructing triple-layered shell microcapsules for multi-functional coating to achieve synergistic protection of anti-/de-icing

Photothermal phase change microcapsules (PCM), which integrate solar-thermal conversion with energy storage, represent one of the most promising materials to address the challenges of intermittent light sources and low energy density. However, such materials often face critical issues in balancing photothermal conversion efficiency and storage capacity, along with structural stability. In this work, a triple-layered shell strategy was proposed to achieve not only stable structure but also a combination of high photothermal conversion efficiency and energy storage in the PCM. In detail, the fabricated PCM utilizes n-octadecane as the core and constructs a triple-layered shell structure composed of silica, polydopamine and copper sulfide via layer-by-layer assembly, achieving full-spectrum absorption with a high photothermal conversion efficiency (95.6%), high latent heat (120 J/g) and excellent stability. The phase change temperature and enthalpy of this PCM remains in good consistency after 100 cycles. Furthermore, the energy transfer is improved due to enhanced thermal conductivity (2.36 W/m·K). Combined PCM with the hydrolysis product of octadecyl trichlorosilane and modified organosilicon resin, a superhydrophobic composite coating with photothermal energy storage is successfully prepared by a two-step method. This coating demonstrates exceptional anti-/de-icing performance under low-temperature condition, offering a synergistic protection mechanism. This study introduces an innovative strategy for developing high-performance PCM and paves the way for anti-/de-icing application of superhydrophobic composite coatings with photothermal energy storage.