Reconfigurable and Mesostructured Liquid-Shelled Capsules

Mesostructured microcapsules with a core-shell structure are good candidates for housing, protecting, delivering, and capturing biocargo. Mesostructured soft-matter shells made from benign materials such as polymers confine the encapsulant within a compatible environment as well as control its mass transport and exchange with the external environment. Synchronous communication of the encapsulants with the changeable external environment requires smart response of the capsule shells for desired molecular exchange. Reversibly stimuli-triggered responsive capsules could regulate the molecular diffusion across the shell by altering its molecular affinity and permeability. However, large property changes upon stimuli and the reversibility of the trigger-response of such dynamic capsules remain a challenge due to limitation of promising soft materials and their fabrication as mesoscaled architectures. Here we introduce reconfigurable and mesostructured liquid-shelled capsules with reversible stimuli-triggered changes of the shell phase composition and structure. Liquids in contrast to polymers offer fast dynamics and in combination with colloidal assemblies and large solid-liquid interfaces can undergo reversible changes of key property metrics without material degradation or fatigue. To this end, we employ microfluidics to template colloidosome microcapsules by introducing surface-functionalized particles in the shell of water-oil-water double emulsions. Upon self-assembly and crosslinking of the colloidal particles, we achieve a porous nearly close-packed particle framework in the liquid double emulsion shell. For colloidosome capsules with reversible stimuli-triggered property change, double emulsions with shell liquids composed of a dual oil system with temperature-dependent miscibility are fabricated. Upon temperature change, the shell undergoes liquid-liquid phase separation, therefore causing the reconfiguration of the double emulsion shell to a two-phase shell, a path towards controlled wetting-dewetting transitions of the porous colloidal shell framework to enable, for example, active closing and opening of the capsules to molecular and particle diffusion.