Effect of Solvent Polarity on Fabrication of Dual Janus Particles with Asymmetric Morphology and Chemical Identity via Photo-initiated Seeded Swelling Polymerization

Particleswith asymmetric morphology or surface chemical identity(Janus) are of great interest in the field of materials due to theirspecial composition and structure. However, it is still a challengeto prepare particles with dual asymmetry via simpleand convenient synthesis strategies. Herein, micron-sized dual-asymmetryJanus particles were prepared via photo-induced seededswelling polymerization within 30 min. By controlling the polarityof the organic solvent (porogenic reagent), Janus particles with variousmorphologies were fabricated. The particles with convex surfaces,such as dumbbell-shaped, snowman-shaped, and golf-shaped morphologies,were obtained in the polar porogenic system, while the concave surfaceparticles, such as bowl-shaped and ball-in-bowl, were acquired inthe non-polar porogenic system. Mushroom-shaped and pinecone-shapedparticles were generated in the binary porogenic system. Particularly,snowman-shaped, bowl-shaped, and pinecone-shaped particles were characterizedby confocal laser scanning microscopy, exhibiting asymmetric chemicalidentity. They could be easily modified into amphiphilic solid surfactantsfor emulsifying oil-water incompatible mixtures with a definiteinterfacial orientation. This strategy provides a possibility forthe simple and rapid preparation of dual Janus particles with asymmetricmorphology and chemical identity, which are expected to be producedon a large scale.