A novel intrinsic photothermal and flexible solid–solid phase change materials with super mechanical toughness and multi-recyclability

The photothermal agents were frequently introduced into phase change materials (PCMs) to attain light harvesting ability, which have imparted PCMs with actively thermal management ability. However, the physical addition of photothermal agents will deteriorate the mechanical toughness and stability of PCMs. Herein, we selected p-benzoquionone dixoime (BQDO) as intrinsic photothermal agent and polyethylene glycol (PEG) as phase change ingredient to fabricate crosslinking polyurethane based photothermal PCMs (PTPCMs). The crosslinking networks can endow excellent solvent resistance and mechanical toughness (149.32 MJ/m3) to PTPCMs, and make for anti-leakage performance of PTPCMs even above melting temperature (Tm) of PEG. PTPCMs can absorb light and store light energy as latent heat via the photothermal conversion of BQDO, which can bring PTPCMs the photo reshaped and photo recovery ability under near-infrared light. Besides, the incorporation of BQDO also brings oxime-urethane bonds, which can process dynamic exchange reaction above the topology freezing temperature (Tv), and impart multi-recyclability to PTPCMs.