Designing New Sustainable Materials through Dynamic Bonds and Supramolecular Strategies

This thesis presents a multidisciplinary exploration of sustainable polymeric materials, emphasizing molecular design, chemical modification, and functionalization strategies to develop bio-based systems with enhanced performance and environmental compatibility. The work integrates concepts from polymer chemistry, supramolecular science, and materials engineering to address current challenges in packaging, water purification, and cosmetic applications. The first part of the thesis focuses on chitosan functionalization through the introduction of hydrogen-bonding motifs and natural chromophores. These modifications were conceived to improve chitosan’s mechanical strength, hydrophobicity, and optical activity while maintaining its biodegradability. The study also explores the incorporation of plant-based extracts to introduce responsive and multifunctional properties suitable for active and smart packaging materials. The second part centers on supramolecular host–guest systems, particularly cavitands designed for the selective recognition of persistent pollutants such as perfluoroalkyl substances (PFAS). Through structural tuning and functionalization, these molecular systems were engineered to achieve specific binding and sensing capabilities, offering insight into their potential use in environmental detection and remediation. Bridging supramolecular chemistry and materials engineering, the thesis investigates polyurethane-based electrospun membranes. Polyurethanes with tailored soft/hard segment ratios are synthesized for stable electrospinning and are used as hosts for covalently or physically incorporated cavitand units. This combination aims to produce nanofibrous membranes that couple high surface area and mechanical integrity with molecular recognition sites for targeted pollutant capture in water purification applications. The work also addresses reactive compatibilization and extrusion of immiscible polymer blends by introducing dynamic covalent functionality to control interphase chemistry and morphology. These processing-led strategies are presented as scalable methods to obtain continuous films and improved barrier/thermal properties in heterogeneous polymer systems. Finally, the thesis explores bio-based UV-active polymers, prepared by grafting or polymerizing natural aromatic chromophores, as sustainable alternatives for intrinsic UV protection in cosmetic and coating applications. Collectively, these research lines form an integrated framework showing how molecular engineering, functional additives, and advanced processing can be combined to create multifunctional, sustainable polymer materials.