(267b) Rheology and Effect of Dispersion on 3D Printing of Chitosan-Graphene-Titanium Dioxide Composites

We have demonstrated the ability for Chitosan-Graphene-Titanium Dioxide (CS-G-T) composites for various fields of water remediation to increase removal density of cyanobacteria, specifically Anabaena sp., Synechocystis sp., and Microcystis aeruginosa in harmful algae blooms. Translating these material compositions to 3D printing opens the potential for tailored kinetics and controlled remediation. In this study, we focus on developing CS-G-T polymer composites for direct-ink-write three-dimensional (3D) printing. We enhanced the dispersion of titanium dioxide and graphene by employing probe sonication with appropriate energy adding a cooling medium to prevent water loss through evaporation. We varied the composition of titanium dioxide while maintaining constant chitosan and graphene composition. Dynamic light scattering and scanning electron microscopy were employed to validate dispersion, resulting in a significant improvement in printability due to the enhanced distribution of titanium dioxide and graphene. We further performed torsional rheological measurements to investigate the shear-thinning behavior and yield stress behavior of the inks, critical for enabling extrusion while limiting spread post-deposition. Further, the addition of a processing aid while printing was found to improve printability and decrease the spreading of the polymer composites by forming a hydrogel upon deposition. These results present a promising approach for enhancing the printability of Chitosan- Graphene-Titanium Dioxide (CS-G-T) Polymer Composite for direct-ink-writing 3D printing. This study further contributes to the understanding of the rheological behavior of C-G-TiO₂ composites and their potential applications in water remediation using 3D printed structures.