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Abstract

This thesis presents the development and evaluation of covalent organic framework (COF)-based nanomaterials for enhancing the active and barrier corrosion protection of epoxy nanocomposite coatings, with a focus on structural tailoring and hybridization strategies. One of the primary objectives was to identify a suitable two-dimensional (2D) nanomaterial for hybridization with COFs. Both MXene and molybdenum disulfide (MoS₂) were initially explored. While MXenes are often considered superior due to their surface functionality, our findings revealed that MoS₂ delivered comparable performance in terms of corrosion protection and durability. Given the complex synthesis routes, higher cost, and environmental concerns associated with MXenes, MoS₂ was selected as the preferred 2D material for subsequent studies. Initially, an imine-linked COF (SNW1) with a high surface area (1163 m².g-¹) was synthesized and hybridized with MoS₂ to create multifunctional nanofillers. Electrochemical impedance spectroscopy (EIS), polarization, salt spray testing, and ICP-MS analysis demonstrated that these hybrid nanomaterials improved both active and barrier protection. However, limitations in long-term performance prompted further investigation into the role of COF morphology, chemical structure, and surface properties. To address this, a structurally engineered COF (TP-TA) was synthesized with a dual-pore architecture and assembled into a flower-like three-dimensional morphology on MoS₂ nanosheets (MDS-COF). Despite its lower surface area (98 m².g-¹), TP-TA COF outperformed SNW1 in corrosion resistance and mechanical durability, owing to its optimized pore structure, redox-active linkages (C=N, C–N), and enhanced dispersion. TP-TA–based coatings maintained protection for up to 126 days, compared to 77 days for SNW1-based systems, and achieved higher total impedance (75,000 Ω.cm² vs. 50,000 Ω.cm²). These results demonstrate that while high surface area improves inhibitor loading, sustained protection depends more critically on chemical structure and morphology. Overall, this research highlights the importance of material selection and rational COF design in developing high-performance nanocontainers, and positions MoS₂ as a more practical and sustainable alternative to MXenes for advanced corrosion-resistant coatings.