Melamine foam/reduced graphene oxide supported form-stable phase change materials with simultaneous shape memory property and light-to-thermal energy storage capability

The advanced utilization of phase change materials (PCMs) is limited by the strong rigidity, liquid leakage and lack of photoabsorption ability. In this work, a novel form-stable PCM with solar-to-thermal energy storage ability and thermal/light-actuated shape memory property was prepared. Herein, paraffin wax (PW) served as a latent heat storage material and a switching phase for shape fixation, melamine foam (MF) acted as a supporting material to prevent the leakage and a permanent phase for shape recovery, and reduced graphene oxide (RGO) assembled on MF skeletons worked as a light absorption medium. Due to the light weight and abundant porosity of MF/RGO foam, the MF/RGO/PW PCMs possessed excellent encapsulation ability, high latent heat (144.8 J/g), good solar-to-thermal energy conversion and storage ability. Simultaneously, combining the elasticity of MF/RGO foam, the MF/RGO/PW PCMs exhibited thermal/light-sensitive shape memory property by triggering the phase transition of PW. The MF/RGO/PW PCMs showed excellent cyclic shape memory performance and thermal reliability. A light-sensitive and temperature-controlled board was further exploited, which could be installed on the roof of the house and maintained the temperature constancy. This study provides a strategy to prepare flexible, light-sensitive and form-stable PCMs via using the elastic MF/RGO foam as a supporting scaffold, and these PCMs have great potential in solar energy utilization and energy-saving buildings.