Shape-stabilized phase change materials based on superhydrophobic polymethylsilsesquioxane aerogels with extremely high paraffin loading for energy storage

Organic phase change materials (PCMs) play an important role in heat energy storage, but they are also limited by the leakage problem in the process of phase change. Herein, shape-stabilized composite PCMs (ssPCMs) are successfully obtained by impregnating paraffin (PA) into the polymethylsilsesquioxane (PMSQ) aerogels. Due to abundant porosity, light weight, inherent superhydrophobic of PMSQ aerogels, lipophilic PA can be loaded into aerogels with a high PCMs loading rate up to 876% without alkylation process. Under the action of aerogel pores, PA in ssPCMs has high degree of crystallinity. The three-dimensional network structure of aerogels can effectively support the melting PA, and there is almost no leakage problem under the strong capillary force and surface tension. The ssPCMs show high latent heat in the range of 117.2 J/g to 122.9 J/g and excellent thermal stability and recyclability where their latent heat nearly remains 97% after 50 times of melting-crystallization cycles. More interestingly, when the temperature reaches above the melting point of PA, the ssPCMs changes from white to translucent. Thus, the synthesized ssPCMs exhibit considerable potential in energy storage applications, temperature intelligent response, thermal regulation.