Advances in Smart Coating Technologies for Wind Turbine Blade Protection: A Focus on Self-Healing and Anti-Erosion Performance

Leading-edge erosion (LEE) of wind-turbine blades, driven primarily by high-velocity rain, particulate impingement, and environmental ageing, remains one of the most pervasive causes of performance loss and maintenance cost in offshore and onshore wind farms. Self-healing coatings, which autonomously or semi-autonomously restore barriers and mechanical function after damage, promise a paradigm shift in blade protection by combining immediate impact resistance with in-service reparability. This review surveys the state of the art in self-healing coating technologies (intrinsic chemistries such as non-covalent interactions or dynamic covalent bonds; extrinsic systems including micro/nanocapsules and microvascular networks) and evaluates their suitability for anti-erosion, mechanical robustness, and multifunctional protection of leading edges. The outcome of the theoretical, experimental, modeling and field-oriented studies on the leading-edge protection and coating characterisation to identify which self-healing concepts best address the simultaneous demands of toughness, adhesion, surface finish, and long-term durability required by wind blade applications. Key gaps are highlighted, notably trade-offs between healing efficiency and mechanical toughness, challenges in large-area and sprayable application methods, and the need for standardised characterisation and testing of self-healing coating protocols. We propose a roadmap for targeted materials research, accelerated testing, and field trials. This review discusses recent studies to guide materials scientists and renewable-energy engineers toward promising routes to deployable, multifunctional, self-healing anti-erosion coatings, especially for wind-energy infrastructure.