Multicompartment Hydrogels.

Hydrogels belong to the most promising materials in polymer and materials science at the moment. As they feature soft and tissue-like character as well as high water-content, a broad range of applications are addressed with hydrogels, e.g., tissue engineering and wound dressings but also soft robotics, drug delivery, actuators, and catalysis. Ways to tailor hydrogel properties are crosslinking mechanisms, hydrogel shape, and reinforcement, but new features can be introduced by variation of hydrogel composition as well, e.g., via monomer choice, functionalization or compartmentalization. In particular, multicompartment hydrogels drive progress toward complex and highly functional soft materials. In the present review the latest developments in multicompartment hydrogels are highlighted with a focus on three types of compartments; micellar/vesicular, droplets, and multilayers including various subcategories. Furthermore, several morphologies of compartmentalized hydrogels and applications of multicompartment hydrogels will be discussed as well. Finally, an outlook toward future developments of the field will be given. The further development of multicompartment hydrogels is highly relevant for a broad range of applications and will have a significant impact on biomedicine and organic devices.