Blueberry-Inspired Structurally Colored PLA Granules Induced by Mie Scattering for Hot-Melt Extrusion of 3D Printing Filaments

The successful development of fused deposition modeling (FDM) printing has stimulated significant market demand for colored poly(lactic acid) (PLA) filaments. However, dye- or pigment-based PLA filaments were susceptible to fading and toxicity risks. Hence, structurally colored PLA filaments urgently need to be developed for their ecofriendliness and sustainability. Herein, we draw inspiration from the disordered structure of the fruit wax, which exhibits selective light scattering on the surface of blueberries. We utilize ZnS spheres supporting Mie scattering covered PLA granules, thereby endowing them with structural color. Structurally colored PLA granules were transformed into PLA filaments with a uniform wire diameter and homogeneous structural color through the hot-melt extrusion method, which were used as materials for FDM printing. The fabricated 3D printed object exhibits an adjustable and vivid structural color, demonstrating excellent resistance to acids, alkalis, and impacts, as well as recyclability, which significantly enhances its potential applications.