Aromatic Schiff Base-Based polymeric phase change materials for Safe, Leak-Free, and efficient thermal energy management

Polymeric phase change materials (PCMs) have garnered enduring interest owing to no leakage and considerable latent heat in thermal management. However, the flammability, poor recyclability, and low energy storage density of typical polymeric PCMs have long-term constraint on their applications in sustainable energy. Herein, we fabricated a novel linear polymeric solid-solid PCM (HPPEG-PU) with facile recyclability, fire safety, and simultaneous high heat transition capacity via introducing aromatic Schiff base structure into the hard segment of HPPEG-PU and meanwhile using high-molecular-weight polyethylene glycol as energy-storage soft segment. HPPEG8000-PU achieved the latent heat of 131.1 J g(-1), higher than the reported polymeric solid-solid PCMs, and realized thermal reprocessing at 80. and fire extinguishment once being ignited. Mechanisms for safe, leak-free, and highly efficient thermal energy storage/release were discussed deeply, in which aromatic Schiff base structure induced network confinement, crystallization, and self-crosslinking charring are highly responsible for shape stability, high thermal storage capacity, and fire safety, respectively. Based on the phase change characteristic of HPPEG-PU, thermosensitive imaging and convenient thermal management applications were developed in this work. Cunningly targeting aromatic Schiff base structure to polymeric PCMs may provide a promising route for safe, leak-free, and efficient thermal energy management.