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Although hydrogel microspheres (microgels) are useful as emulsion stabilizers, typical microgels cannot stabilize foams over a prolonged period of time. Here, we found that compressible nanocomposite microgels with solid nanoparticles can overcome undesired desorption of microgels from the air/water interface of bubbles, and form highly durable, microgel-surrounded foams (gelfoams). [ABSTRACT FROM AUTHOR]

The three‐dimensional structure of nanocomposite microgels was precisely determined by cryo‐electron micrography. Several nanocomposite microgels that differ with respect to their nanocomposite structure, which were obtained from seeded emulsion polymerization in the presence of microgels, were used as model nanocomposite materials for cryo‐electron micrography. The obtained three‐dimensional segmentation images of these nanocomposite microgels provide important insights into the interactions between the hydrophobic monomers and the microgels, that is, hydrophobic styrene monomers recognize molecular‐scale differences in polarity within the microgels during the emulsion polymerization. This result led to the formation of unprecedented multi‐layered nanocomposite microgels, which promise substantial potential in colloidal applications. [ABSTRACT FROM AUTHOR]

Soft colloidal particles such as hydrogel microspheres assemble at air/water or oil/water interfaces, where the soft colloids are highly deformed and their surface polymer chains are highly entangled with each other. Herein, we report the formation of robust one‐dimensional, string‐like colloidal assemblies through self‐organization of hydrogel microspheres with shape anisotropy at the air/water interface of sessile droplets. Shape‐anisotropic hydrogel microspheres were synthesized via two‐step polymerization, whereby a hydrogel shell was formed onto preformed rigid microellipsoids. The shape anisotropy of the hydrogel microspheres was confirmed by transmission electron microscopy and high‐speed atomic force microscopy as well as by light‐scattering measurements. The present findings are crucial for the understanding of natural self‐organization phenomena, where "softness" influences microscopic assembled structures such as those of Nostoc bacteria. [ABSTRACT FROM AUTHOR]

Titelbild: Hydrophobic Monomers Recognize Microenvironments in Hydrogel Microspheres during Free-Radical-Seeded Emulsion Polymerization (Angew. Keywords: cryo-electron microscopy; hydrogel microspheres; microgels; nanocomposite materials; seeded emulsion polymerization EN cryo-electron microscopy hydrogel microspheres microgels nanocomposite materials seeded emulsion polymerization 8809 8809 1 05/27/20 20200602 NES 200602 B Kryo-Elektronenmikrographie b wurde verwendet, um die dreidimensionale Struktur von Mikrogelen präzise zu bestimmen und Einblick in die Wechselwirkung zwischen kleinen hydrophoben Molekülen und den Mikrogelen zu gewinnen. Cryo-electron microscopy, hydrogel microspheres, microgels, nanocomposite materials, seeded emulsion polymerization. [Extracted from the article]