| 초록 |
We present a facile and promising strategy for fabricating magnetically responsive composite particles with geometric of anisotropy controlled by external fields. A microfluidic method is used to generate monodispersed emulsion droplets composed of polystyrene, magnetite nanoparticles (MNPs), and chloroform. While the solvent in the droplets is dried in the presence of an external magnetic field, the emulsion droplets are deformed or elongated along the field direction, consequently leading to magnetically responsive particles with anisotropic shape after complete removal of the solvent. Coarse-grained molecular dynamic simulations demonstrate that the shape deformation is due to destabilization of the MNPs upon solvent drying and migration of the aggregated MNPs in the polymer matrix under the external field. The particle shape could be readily tunable by modulating the field strength and direction as well as the concentrations of the MNPs and polymer. We also reveal that these magnetically anisotropic particles can be used as micro-stirring particles to efficiently mix a small confined volume of fluids (e.g., microemulsion reactor systems). |
