Design and Formulation of Catechol-Containing and Functionally Related Styrenic Copolymers for Enhanced Underwater Adhesion

<p dir="ltr">The development of advanced adhesive materials capable of performing reliably in underwater environments is essential for a wide range of applications, including marine construction, biomedical devices, underwater robotics, and waterproof consumer products. This thesis presents a comprehensive exploration of mussel-mimetic catechol-containing adhesives, emphasizing formulation strategies, adhesion mechanisms, and the relationship between material properties and performance of poly(vinylcatechol-styrene) (PVCS) and related styrenic copolymers. In Chapter 1, we review the challenges of underwater bonding, biological adhesion strategies evolved by marine organisms, and synthetic polymers designed to mimic natural adhesion mechanisms.</p><p dir="ltr">Chapter 2 explores the potential of catechol-containing polymers for underwater bonding, and highlights poly(vinylcatechol-styrene) as a leading underwater adhesive. We examined the barriers to commercialization of PVCS-based adhesive systems, including the lack of a scalable, cost-effective synthetic route capable of competing with long-established adhesive chemistries such as epoxies, cyanoacrylates, and polyurethanes. A novel four-step synthetic route, including a two-step in-house monomer preparation, was introduced to improve efficiency, safety, and batch scalability. Chapter 3 focuses on the next critical step following the improved synthesis of PVCS, i.e<i>.</i>, adhesive formulation and product workability. We replaced traditional PVCS-based formulations that often rely on toxic, highly regulated solvents with a safer solvent system, and developed a versatile library of formulations adaptable to various applications, substrates, and environmental conditions.</p><p dir="ltr">Chapter 4 introduces a three-tiered strategy to address the presence of bulk, trapped, and interstitial water at the bonding interface. This approach integrated physical, physicochemical, and chemical mechanisms by combining a hydrophobic matrix (physical), water-absorbing fillers (physicochemical), and functional moieties analogous to catechol (chemical) to effectively displace interfacial water and enhance adhesion performance. Finally, Chapter 5 studies the rheological behavior of catechol-based hydrogels under physiologically relevant conditions, aiming to optimize their use in biomedical applications for drug delivery and skin adhesion.</p><p dir="ltr">The work presented here advances the understanding and application of biomimetic adhesives, and paves the way for the introduction of a new adhesive chemistry to the marketplace.</p>