Crafting Tunable Hollow Particles Using Antisolvent-Driven Interlocking of Micron-Sized Building Blocks

The contribution of a hollow structure on the rheological behavior of granular suspensions remains un-investigated due to the challenge of water impermeability. Here starch is used to fabricate water-permeable hollow particles, as a model for granular suspensions and investigated the resulting microstructures and rheological behavior. The hollow structure is fabricated based on a bottom-up method by assembling micron-sized building blocks into a superstructure. A Pickering emulsion is heated to fuse the starch interface, then, upon antisolvent precipitation, the polymer strands interlock to form a rigid shell around the oil template. When the template is removed a hollow particle remained. These particles exhibited a specific volume >5-times higher than unmodified starch and consequently a higher viscosity. Larger particles showed higher viscosity but are also more fragile. The template structure can be manipulated to fine-tune their functionality. These micro-sized building blocks made from edible materials can be used as the next generation of texturizers. Additionally, these water-permeable colloidosomes present an innovative approach to understanding how micro-architectures impact the rheological behavior of granular suspensions.