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

Abstract

Particles with asymmetric morphology or surface chemical identity (Janus) are of great interest in the field of materials due to their special composition and structure. However, it is still a challenge to prepare particles with dual asymmetry via simple and convenient synthesis strategies. Herein, micron-sized dual-asymmetry Janus particles were prepared via photo-induced seeded swelling polymerization within 30 min. By controlling the polarity of the organic solvent (porogenic reagent), Janus particles with various morphologies 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 surface particles, such as bowl-shaped and ball-in-bowl, were acquired in the non-polar porogenic system. Mushroom-shaped and pinecone-shaped particles were generated in the binary porogenic system. Particularly, snowman-shaped, bowl-shaped, and pinecone-shaped particles were characterized by confocal laser scanning microscopy, exhibiting asymmetric chemical identity. They could be easily modified into amphiphilic solid surfactants for emulsifying oil–water incompatible mixtures with a definite interfacial orientation. This strategy provides a possibility for the simple and rapid preparation of dual Janus particles with asymmetric morphology and chemical identity, which are expected to be produced on a large scale.

Anisotropic Magnetic Polymeric Particles with a Controllable Structure via Seeded Emulsion Polymerization

“…Anisotropic particles have been proven to be useful for wide applications, which serve as rheological dopants for coatings, catalysts, electronics, pharmaceuticals, , and solid surfactants. , In previous works, anisotropic magnetic particles have been prepared by various physical and chemical methods. , They include (1) in situ polymerization of monomers in the presence of iron-oxides, emulsion polymerization, dispersion polymerization, or suspension polymerization; − (2) microfluidic techniques, using templated asymmetric droplets to achieve anisotropic magnetic particles; and (3) microcontact printing techniques by fabrication of asymmetrically coated colloidal particles. , Wang and co-workers prepared programmable microfluidics enabled by 3D printed bionic Janus porous matric . The limitation of microfluidic technology is that its device must be very fine to control the coordinated movement or uniform mixing of its monomer and magnetic substances, otherwise, it will cause its output to be unstable or disordered .…”

Preparation of Asymmetric Al2O3-SiO2 Janus Nanoparticles in Aqueous Phase and Its Interfacial Property

“…Since then, research on Janus nanoparticles has been thriving, and they have received considerable attention due to their unique physical, chemical, and biological properties [ 8 ]. Different techniques such as masking, bottom-up assemblies, and controlled phase separation have been employed to synthesize Janus nanoparticles [ 9 , 10 ], and various Janus architectures have been created, such as cylindrical-shaped [ 11 ], dumbbell-shaped with asymmetric or snowman characters [ 12 , 13 , 14 , 15 , 16 , 17 ], mushroom-shaped [ 18 , 19 ], bowl-like [ 20 , 21 ], crescent-shaped [ 22 , 23 ], and half-raspberry-shaped structures [ 24 ]. Among these, dumbbell-like nanoparticles, as a prominent subset of Janus nanoparticles, have attracted significant interest due to their unique structure and excellent performance in various application domains, including drug delivery, catalysis, sensing, and advanced materials.…”