Additive and hydrogel applications in photoinduced 3D printing manufacturing

The present thesis constitutes a multidisciplinary investigation into the development of advanced photopolymerizable materials for additive manufacturing using photoinduced 3D printing techniques. The research focuses on the synthesis and application of addition-fragmentation monomers (AFMs) and dynamic disulfide-based hydrogels. In addressingcritical limitations in 3D printing, the research focuses on polymerization shrinkage stress, mechanical brittleness, and uncontrolled release profiles in biomedical applications. A novel sulfur-free AFM crosslinker was synthesized via cobalt-mediated catalytic chain transfer polymerization and incorporated into custom resin formulations. The integration of AFMs into digital light processing (DLP) printing resulted in a substantial reduction in internal stresses through reversible bond exchange mechanisms, while preserving structural fidelity and mechanical performance. Systematic studies revealed optimized concentrations for enhanced tensile strength and reduced shrinkage, with kinetic and rheological analysis validating the dynamic stress-relieving capabilities of the network. Concurrently, peptide-carrying hydrogels were fabricated using disulfide-containing crosslinkers, thereby enabling redox-responsive drug release via thiol-disulfide exchange. These hydrogels have been shown to exhibit tunable swelling behaviour, high loading efficiency, and controlled release of model peptides, including lanreotide and calcitonin. The thesis further extends this work by engineering multifunctional tertiary amine crosslinkers, introducing antimicrobial activity and pH-responsiveness into printed hydrogels. The research contributes to the advancement of the field of photoinduced 3D printing by combining innovative polymer chemistry with precision manufacturing. This enables new functional materials for stress-reducing structural applications and intelligent drug delivery platforms. This work makes a substantial contribution to the existing body of knowledge concerning dynamic covalent systems in 3D printing, thereby establishing the foundation for future innovations in the biomedical and industrial sectors.