Patchy colloidosomes – an emerging class of structures

Abstract

Abstract.A colloidosome, i.e., a selectively permeable capsule composed of colloidal particles forming a stable homogenous shell, is a tiny container that can be used for storage, transportation, and release of cargo species. There are many routes to preparing colloidosomes; dozens of examples of future applications of such colloidal capsules have been demonstrated. Their functionality can be further extended if the capsules are designed to have heterogeneous shells, i.e., one or more regions (patches) of a shell are composed of material with specific properties that differ from the rest of the shell. Such patchy colloidosomes, supplemented by functionalities similar to that offered by well-studied patchy particles, will surely possess advantageous properties when compared with their homogenous counterparts. For example, owing to specific interactions between patches, they either can self-assemble into complex structures; specifically adhere to a surface; release their cargo species in specific direction; or guided-align,-orient or -propel. Fabrication of patchy colloidal microcapsules has long been theorized by scientists able to design different models, but actual large-scale production remains a challenge. Until now, only a few methods for fabricating patchy colloidosomes have been demonstrated, and these include production by means of microfluidics and mechanical pipetting. The field of science related to fabrication and application of patchy colloidosomes is clearly unexplored, and we envision it blooming in the coming years.

Colloidal capsules: nano- and microcapsules with colloidal particle shells

“…207 For more colloidal capsules with a patchy surface structure we recommend the recent review by Rozynek and Jozefczak. 208 Besides these MOF-based and bimodal structures, a variety of capsules with oblong building blocks have been reported. Noble and co-workers first reported the use of microrods for the stabilization of a Pickering-like emulsion and subsequent capsule formation.…”

Particle-covered drops in electric fields: drop deformation and surface particle organization

“…8 Moreover, such drops possess characteristics that make them useful as experimental model systems for studying, for example, particle effects on interfacial tension, 9 particle crystal growth and ordering or particle layer buckling on curved interfaces, [10][11][12][13] particle assembly and rearrangement on drop surfaces, 14,15 and particle detachment from drops. 16 Particle-covered drops can additionally be employed for fabricating porous structures, 17 granular or colloidal capsules of different mechanical properties, morphologies, or shapes, 18,19 and adaptive structures. 20 In this context, broadening knowledge of particle-covered drop stability, deformation, and surface particle manipulation is essential to further developing the abovementioned research areas.…”

Electro-Hydrodynamics of Emulsion Droplets: Physical Insights to Applications

“…Based on this techniques, Nudurupati et al demonstrated that it was able to extract particles inside the droplet [ 170 ] ( Figure 11 C). Rozynek et al suggested that the release rate of some areas of the droplet, named releasing holes, can be increased by rearranging the particles using an electric field [ 171 ] ( Figure 11 D).…”

“…( C ) Removal or collection of particles from a w/o emulsion using an electric field [ 170 ]. ( D ) The releasing holes for material transportation from/to the capsule [ 171 ].…”