Phase separation occurs in emulsion droplets containing poly (ethylene glycol) diacrylate (PEGDA), glycerol, and ethanol to form a glycerol-in-PEGDA structure, and the phase separation process is found to depend on the droplet size. The mechanism of this size-dependent phase separation is dependent on the droplet sizes changing the phase separation time by changing the evaporation speed of mutual solvent ethanol, and the relationship between the separation time T and the droplet diameter D is derived as T≈D , which has been validated by experiment results. According to this finding, the structures of the droplets can be designed by applying UV curing at different stages of the phase separation, and the monodispersity of droplets is necessary to achieve polymerized particles with the same structure.

The front cover artwork is provided by the Microfluidic and Interface Group (Prof. Haosheng Chen and Prof. Jiang Li). The image shows the phase separation process of PEGDA, glycerol, and ethanol tenary mixture, which is driven by the evaporation of ethanol. When applying UV‐treatment at different stages of phase separation, we can get microparticles with different structures, such as core‐shell and bowl structures. Read the full text of the Article at https://doi.org/10.1002/cphc.201701296.

The Front Cover shows a river flowing downstream from a pyramid and containing microspheres with different structures. The pyramid represents the ternary diagram of poly(ethylene glycol) diacrylate (PEGDA), glycerol, and ethanol mixtures. Microspheres with different structures on the river represent microspheres at different stages of the phase‐separation process and the sun symbolizes the ultraviolet light used to polymerize PEGDA and stop phase separation. More information can be found in the Article by J. Man et al. on page 1995 in Issue 16, 2018 (DOI: 10.1002/cphc.201701296).