Mechanically Robust and Environmentally Stable Solid–Solid Phase Change Materials via Thiolactone Strategy for Versatile Applications

Abstract Solid–solid phase change materials (SSPCMs) have received great interest due to their exceptional thermal management and superior shape stability. However, traditional crosslinked structures predominantly rely on ester groups, which limits their applicability under extreme conditions such as high humidity. Herein, a novel strategy is presented for preparing SSPCMs with excellent latent heat and environmental robustness via thiolactone ring‐opening reactions. Easily synthesized thiolactone copolymers provide abundant reactive sites which are then functionalized with alkyl amines and alkyl acrylates as grafted phase change components. A small amount of polyetheramine is employed to crosslink the functionalized copolymer, forming a robust network. The resulting SSPCMs exhibit tunable phase transition temperatures (44.7–61.0 °C) and enthalpies (20.3–98.9 J g ⁻¹ ). Owing to the high density of alkyl groups, the SSPCMs can maintain the stability of mechanical properties, phase change properties, and shape when immersed in water, acid, and alkaline conditions for 2 h. In addition, the synthesized phase change films demonstrate reversible information encryption, shape memory and infrared stealth properties. When integrated with polydopamine nanoparticles, these materials also exhibit excellent solar‐thermal stores/releases capacity. Collectively, these unique features provide new insights and ideas for the development of the next generation of smart thermal management materials.