Controlling porosity in colloidal supraparticles using rod–sphere particle mixtures

Supraparticles (SPs), large assemblies of smaller particles, are versatile materials whose properties can be tailored through the chemistry and arrangement of their constituent particles. Porous SPs with significant internal void space are particularly promising for their catalytic, photonic, and physical absorption properties. In this study, we performed simulations to explore the drying-induced formation of SPs made from spherical filler particles and rod-shaped particles. After formation of the final SP structure, the removal of filler particles can result in a highly porous structure. The volume fraction between spherical and rod-shaped particles plays a key role in shaping the overall structure and porosity, while increasing the aspect ratio of the rods further amplifies this effect. Additionally, we observed that faster drying rates lead to a distinct increase in porosity. These insights into the increasing the porosity through particles size, shape, and drying conditions provide a valuable framework for designing highly porous SPs.