Intelligent Self-Healing Polymeric Systems for Functional and Durable Coatings.

Self-healing polymeric coatings represent a transformative class of smart materials capable of autonomously or stimuli-responsively repairing mechanical or environmental damage, thereby significantly extending the operational lifespan of protected substrates. This review systematically elucidates the underlying mechanisms and chemistries enabling self-healing behavior, encompassing both extrinsic strategies such as microcapsules, microvascular networks, and corrosion inhibitor reservoirs and intrinsic approaches based on dynamic covalent (e.g., disulfide exchange, Diels-Alder, imine, transesterification/vitrimer networks) and supramolecular interactions (e.g., hydrogen bonding, metal-ligand coordination, ionic, and host-guest systems). Emphasis is placed on recent advances in external stimuli-responsive systems triggered by heat, light, moisture, pH, electricity, or magnetic fields. The performance of these coatings under extreme conditions, including corrosive media, marine environments, thermal cycling, mechanical fatigue, and high-voltage fields, is critically evaluated. Furthermore, this review highlights industrial translation through commercial exemplars (e.g., NANOMYTE® MEND, BASF Elastocoat, Baydur HC, FEYNLAB), scalable fabrication routes (spray coating, dip-coating, UV-curing, and 3D/4D printing), and alignment with sustainability goals. Challenges such as multifunctional integration, interfacial adhesion, regulatory compliance, and the need for standardized evaluation metrics are discussed. Finally, future directions in predictive molecular design and high-throughput screening are outlined to accelerate the development of next-generation self-healing coatings (SHC) across diverse Asian industrial sectors.