Design And Development of Self-Healing Nanocomposites for High-Performance Applications in Extreme Environments

ABSTRACT: Self-healing nanocomposites represent a paradigm shift in materials science, offering autonomous damage repair capabilities crucial for high-performance applications in extreme environments. This review examines recent advances (2020-2025) in the design, synthesis, and characterization of self-healing nanocomposite systems engineered for operation under harsh conditions including elevated temperatures, aggressive chemical exposure, mechanical stress, and radiation environments. We comprehensively analyse intrinsic and extrinsic healing mechanisms, including dynamic covalent bonding, supramolecular interactions, microcapsule-based systems, and vascular networks integrated with nanoscale reinforcements. The synergistic effects of nanofillers such as graphene, carbon nanotubes, metal-organic frameworks, and ceramic nanoparticles on mechanical properties, thermal stability, and healing efficiency are critically evaluated. Applications in aerospace, energy storage, protective coatings, and biomedical devices are discussed, highlighting the multifunctional performance requirements. Current challenges including healing kinetics at low temperatures, repeated healing cycles, and scalability for industrial production are addressed. This review provides insights into future directions for developing next-generation autonomous materials capable of extending service life and enhancing reliability in demanding operational conditions. Keywords: Self-healing polymers, Nanocomposites, Extreme environments, Autonomous repair, Dynamic chemistry, Nanomaterials.