A Comprehensive Review on Gas Barrier Polymer Nanocomposites: Materials, Characterization, Synthesis, Applications, and Modelling Approaches

Abstract Polymeric nanocomposites (PNCs) represent a transformative class of materials, offering remarkable advancements across scientific and industrial domains. By incorporating organic, inorganic, or hybrid nanomaterials into polymer matrices, PNCs achieve significant enhancements in mechanical, thermal, electrical, chemical, and gas barrier properties. The exceptional gas barrier performance of PNCs is particularly vital for aerospace applications, where materials must endure extreme conditions, including low pressure, temperature fluctuations, and exposure to harsh environments. Beyond aerospace and defence, PNCs are revolutionizing applications in packaging, sustainable materials, and advanced electronics, emerging as a superior alternative to traditional polymeric systems. This review highlights the latest advancements in the synthesis, characterization, and application of impermeable polymer nanocomposites. It discusses the state‐of‐the‐art research on the use of platy fillers (e.g., clay and graphene) including biodegradable fillers for the gas barrier performance of PNCs. It also provides insights into innovative synthesis techniques such as melt intercalation, solution blending, in situ polymerization and LbL assembly including predictive modelling approaches, such as molecular dynamics simulations that enable the design of high‐performance materials with tailored properties. Furthermore, it explores the interdisciplinary potential of PNCs, including their role in clean energy storage, flexible electronics, and biomedical applications. By addressing current challenges and opportunities, this review underscores the pivotal role of PNCs in driving innovation across multiple high‐performance industries.