Physically cross-linking phase change aerogels with moldability and structural thermostability for thermal management

Phase change aerogels typically designed by encapsulating phase change materials (PCMs) into aerogel framework are promising for the thermal management applications, yet their poor structural thermostability due to solid-liquid transition incurs PCMs leakage and weak resistance against mechanical disturbance, limiting practical applications. Herein, the unconventional self-supporting solid-solid phase change aerogels with moldability and structural thermostability produced from polyurethane containing PEG segments at the backbone were designed. The robust physical crosslinkers ensured the solid-solid phase change and rendered exceptional mechanical properties (tensile stress of 57 MPa) and re-processability. Most importantly, the PCMs aerogels can maintain porous structures and thermal insulation stability at 60 °C for numerous cycles, in sharp contrast to the melt leakage of PCMs encapsulated in aerogels. Taking the advantages of porous structures, latent heat of phase change and passive radiation capacity, the PCMs aerogels promised great potential for building energy efficiency. The building energy simulations suggested that the energy consumption could be reduced ∼42 % in certain Chinese cities. Thus, this study offers not only a combinational strategy of designing PCMs with balanced phase change enthalpy and mechanical properties, but also PCMs aerogel platform for moldability, thermostability and thermal insulation applicable in thermal management.