Strong and tough double network hydrogels based on poly(2-oxazoline) and polyacrylates

Double network hydrogels (DNHs) are known for their exceptional stiffness, toughness, and tunable characteristics, making them valuable for applications in membrane technology, energy storage, and, of significant importance, in biomedicine. These materials show great potential for replicating complex biomaterials such as cartilage. This work presents, for the first time, the development of DNHs based on poly(2-oxazoline) as the primary network and various polyacrylates as the secondary network, resulting in materials with remarkable toughness. The thesis is structured into three main parts, each addressing different features and challenges involved in developing these DNHs. The first section focuses on the synthesis and optimization of DNHs using poly(2-oxazoline)s (POx) and poly(acrylic acid) (PAA), yielding materials with biomechanical properties comparable to cartilage, including high compressive strength and durability under physiological conditions. The second section further explores the potential of POx-based DNHs by incorporating various polyacrylates as secondary networks. This part emphasizes the investigation of interactions, functional groups, and the structural influence of the networks involved on the mechanical performance of the resulting hydrogels, achieving superior mechanical properties compared to conventional DNHs composed solely of polyacrylate networks. Additionally, the thesis addresses the critical challenge of maintaining hydrogel functionality across a wide pH range, essential for implantable materials exposed to varying tissue environments and inflammatory responses. A novel DNH formulation, comprising poly(2-methyl-2-oxazoline) and poly(acrylic acid-co-acrylamide) P(AA-co-AAm), is developed, demonstrating remarkable stability and mechanical integrity across pH levels from 3.4 to 10.5. Through extensive mechanical testing, this research highlights the robustness and versatility of these advanced DNHs, positioning them as strong candidates for use in tissue regeneration, implants, and other biomedical applications where durability and adaptability are crucial. This work contributes significantly to the understanding and application of DNHs in complex physiological environments.