Intrinsic self-healing Polyurethanes: Advances, Applications, and future prospects

Polyurethane (PU), a versatile and widely used polymer, has garnered significant research attention due to its intrinsic properties such as extended lifetime and durability, with diverse applications, ranging from clothing to industrial components. Self-healing mechanisms in PU primarily rely on intrinsic and extrinsic driving forces, in which the intrinsic process got sough after because of its reversible features. The intrinsic mechanism can be categorized into reversible covalent bonds (e.g., Diels-Alder reactions and disulfide bonds,) and dynamic non-covalent interactions (e.g., hydrogen bonds and ionic bonds). These mechanisms enable the spontaneous reconfiguration and healing of the polymer structure. Furthermore, the integration of new functional groups into PU structures introduces additional properties such as shape memory, degradability, and biocompatibility, broadening the scope of applications, particularly in flexible sensors and biomedical engineering. This paper delves into the self-healing mechanisms of PU, its functional integration, and potential applications in emerging fields such as coatings, adhesives, photo-thermal conversion, and biomedical devices, highlighting the challenges and future prospects in the development of self-healing PUs. Through a synthesis of recent studies, this article also discusses the balance between self-healing capabilities and mechanical properties, proposing new research directions for enhancing the efficacy and utility of self-healing PUs.