Reinforcement of Hydrogels via Polyacrylic Acid Nanoparticles Induced Calcium Carbonate Crystallization

Hydrogel materials have been an area of research over the past 50 years. These polymer materials have many applications including, but not limited to, pharmaceuticals, cosmetics, 3-D printing, and biomedical applications. However, hydrogels can inherently be soft and brittle. Many hydrogel materials suffer from poor compressive resilience and an inability to stretch without breaking. The ability to produce stronger more resilient materials has been an important area of research due to the potential applications of these materials. Several biologic systems use soft tissue as scaffolding for the development of bones and shells. These systems have been a source of inspiration for polymer chemists who hope to create a stronger hydrogel material. This master’s thesis set out to evaluate the effectiveness of using hydrogel materials as chemical scaffolding for CaCO¬¬3 crystallization. This was evaluated by producing a hydrogel from polyacrylic acid nanoparticles and then inducing crystallization of CaCO3 throughout the system. This system’s loss and storage modulus was evaluated using rheologic frequency sweeps to determine how the material’s properties change after the addition of calcium ions and after the crystallization of CaCO3. The next system that was evaluated was the effect of both the nanoparticles and carboxylic acid functionalities on the hydrogel’s material properties during every step of the crystallization process. The last system that was evaluated was the effect of changing the molecular weight of the backbone of the hydrogel. Four different polyethylene glycol polymer backbones were synthesized and then used to produce hydrogels. These systems’ material properties were also evaluated at every step of the crystallization process with rheologic frequency sweeps