Microwave-Assisted Self-Organization of Colloidal Particles Inside Water-in-Oil Emulsions

Abstract

Commercial amidine polystyrene microspheres were self-organized to obtain colloidal microclusters from water-in-oil emulsion droplets as confining geometries. For demulsification process, microwave was irradiated to remove water droplets selectively resulting in the shrinkage of water droplets which induces inward capillary pressure for the particle self-assembly. The amidine polystyrene clusters were coated with silica nanospheres or titania nanoparticles by co-organizing the mixed particle suspensions inside water droplets by microwave heating. Titania-coated polystyrene clusters were calcined to produce hollow macroporous titania powders. Finally, sulfate-coated polystyrene microspheres were self-assembled with silica nanoparticles to generate polystyrene/silica composite clusters by microwave irradiation method.

Keywords:

• Colloidal clusters
• macroporous titania powder
• microwave irradiation
• self-assembly

Acknowledgments

G.-R. Yi acknowledges the support by the NRF grant (2009-0082451) funded by the MEST. The authors also acknowledge the Korea Basic Science Institute for scanning electron microscopy and transmission electron microscopy.

Notes

Current address for Y.-S. Cho: Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

Current address for G.-R. Yi: Department of Industrial and Engineering Chemistry, Chungbuk National University, Heungdeok-gu, Cheongju, Republic of Korea.