Design of Sustainable Self‐Healing Phase Change Materials by Dynamic Semi‐Interpenetrating Network Structure

Abstract The design of sustainable self‐healing phase change materials (SHPCMs) remains challenging depending on sustainable fatty alcohols without compromising high enthalpy efficiency. Herein, the semi‐interpenetrating network (semi‐IPN)‐based SHPCMs are developed by introducing dynamic disulfide crosslinking polyurethane networks and sustainable fatty alcohols as phase change components in a semi‐IPN structure, enabling the combination of ultrahigh enthalpy efficiency of ≈100% and excellent self‐healing ability with 99% of mechanical stain healing efficiency. The latent heat (61.6–144.3 J g −1 ) and phase change temperature (29.2–64.2 °C) can be readily adjusted by the type and content of fatty alcohols in SHPCMs. The SHPCMs present high thermal reliability, thermal and shape stability, and solid‐like rheological properties benefiting from the advantage of the semi‐IPN structure. The SHPCMs are endowed with tunable mechanical stress (1.23–6.16 MPa) and strain (5.77–379.48%). More importantly, the SHPCMs can be nearly completely self‐healed after thermal stimulus, complying with the Arrhenius model, with a low activation energy of 33.831 kJ mol −1 . This innovative strategy opens new avenues for preparing efficient and durable thermal energy storage materials with high enthalpy efficiency, self‐healing ability, and sustainable phase change components, broadening their potential applications.