3D Printed Hierarchical Gyroid Structure with Embedded Photocatalyst TiO2 Nanoparticles

Natural hierarchical structures, such as tree leaves or butterfly wings, have been broadly studied due to their exclusive functions, including ultralight nature, higher surface area-to-volume ratio, and high chemical reaction efficiency. In this study, we develop a 3D printed hierarchical gyroid structure with embedded TiO2 nanoparticles (NPs) to investigate its effective photocatalytic structural performance for long-term application. Fused deposition modeling 3D printing is used to fabricate a gyroid structure with a functionalized photodegradable polylactic acid (PLA) containing embedded TiO2 NPs. The porous and 3D network gyroid structure provides more light pathways and surface area, which increases the contact interface and rapid mass transportation under UV irradiation. In addition, as the PLA is photodegraded at the surface over time, improved hierarchies are created within the structure. It allows the embedded TiO2 NPs to be continuously exposed to the surface along the hierarchical structure. As a result, the hierarchical gyroid structure not only maintains its reaction efficiency but also exhibits better adsorption and faster photocatalytic ability by the formation of additional voids as the reaction time is prolonged. This structural and material design approach will suit well for various applications, such as drug-eluting devices, water purification filters, or energy-harvesting devices.