Healable supramolecular phase change polymers for thermal energy harvesting and storage

Phase change materials (PCMs) have been widely applied in latent heat storage technologies via harvesting thermal energy from the surrounding environment, however, they are vulnerable to damages when suffering from an external stimulus or environmental attacks, resulting in crack formation and lifespan reduction. Herein, a strategy was proposed to fabricate a series of healable supramolecular phase change polymers (HOPs), in which poly(4-vinylpyridine) (P4VP) composed the backbones with stearic acid (SA) as the side chains, and polypyrrole (PPy) was incorporated into the dynamic hydrogen-bonding networks within HOPs. The obtained HOPs exhibited excellent anti-leakage capability and long-term durability with stable energy storage capacity (111.5 J/g). In addition, via 1000 times solar irradiation experiments they demonstrated high cycling stability and reversible solar-thermal energy conversion and storage ability that are crucial for practical applications. More importantly, cracks or scratches in the HOPs can be rapidly self-repaired upon an input of external heating or light due to the hydrogen-bonding interaction, which prolongs their service life and reduces waste generation and accumulation. This successful approach may open up new ideas for designing and developing the next generation of smart thermal energy storage materials.