Self-inflating Colloidal Microcapsules

Hollow-structured particles have attracted great attention in both nanomaterials and colloidal science due to their high surface area and unique spatial confinement. Here I will present a self-inflation method to produce 3-(trimethoxysilyl)propyl methacrylate(TPM) based colloidal microcapsules with versatile design and tunability of structures. Detailed mechanistic study revealed the process is the result of a fine balance between surface tension and osmotic pressure from partial hydrolysis of TPM network. Microcapsule sizes can be accurately controlled by adjusting the osmotic pressure due to the semipermeable property of the membrane. We further demonstrate the feasibility of introducing an opening hole onto the capsules by hard-templating on a removable seed, and the whole network can be solidified to maintain stable and rigid morphology. Large-scale synthesis of monodisperse polymeric microcapsules with tunable and uniform hole can be easily obtained. As a result, these model particles laid solid foundation for studying fluid mechanics, self-assembly, packing and jamming in confinement, and showed great potential in dynamic transport, storage, separation and delivery of drugs or particles.