Double-Cross-Linking of Polystyrene for the Fabrication of Snowman-Shaped Janus Nanoparticles for Emulsion Stabilization

This study proposes a double-cross-linking strategy for preparing snowman-shaped Janus nanoparticles using low cross-linked polystyrene (PS) microspheres as seeds. By introducing silica (SiO2) to form a composite structure with PS, the resulting nanoparticles exhibit significant amphiphilicity, with one hemisphere being hydrophobic PS and the other hydrophilic SiO2. The effect of silica source addition and the cross-linking degree of seed microspheres on the morphology of the snowman nanoparticles was investigated. The results indicate that the slow addition of the silica source effectively suppresses morphological distortion, enhancing the continuity and stability of the synthesized product. Furthermore, introducing a double-cross-linking strategy significantly improves the solvent resistance of the particles, ensuring their structural stability in various chemical environments. Additional characterization and testing confirm that the Janus nanoparticles can be functionally modified through chemical grafting (amination and fluorosilane modification), demonstrating their potential applications in emulsion stabilization. This work provides a feasible approach for replacing traditional hollow polystyrene microspheres as seeds in preparing functional Janus nanoparticles.