COLL 546 |
| Orlin D. Velev, Ketan H. Bhatt, Brian G. Prevo, David G. Woolard, and Jeffrey R. Millman. Department of Chemical Engineering, North Carolina State University, Riddick Hall, Raleigh, NC 27695 |
| Dielectrophoresis, particle polarization and mobility in alternating electric fields, allows manipulation and precise control of the interactions and assembly of colloid particles. We have developed tools for dielectrophoretic manipulation and assembly of microparticles and nanoparticles by planar on-chip electrodes. The on-chip dielectrophoresis was also used to transport and manipulate droplets in a novel liquid-liquid microfluidics system. Water and hydrocarbon droplets suspended on the surface of a denser liquid were driven by electric fields created by addressable arrays of electrodes immersed in the oil. These liquid-liquid chips open a range of materials synthesis applications that are not available with conventional microfluidic devices. We show how the liquid-liquid chips allow automated microfabrication. The droplets could serve as self-contained templates and reactors for the assembly of particles with advanced structure. Controlled on-chip mixing and drying of droplets containing latex microsphere suspensions was used to form supraparticles of colloidal crystals, and anisotropic composite particles. Formation of oil-water and polymer-water capsules was also demonstrated. Future applications of the method could include massively parallel microscopic bioassays and combinatorial synthesis. |
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“Smart” Polymers on Surfaces and Colloids
2:00 PM-4:50 PM, Thursday, April 1, 2004 Marriott -- Grand Ballroom J, Oral
Division of Colloid and Surface Chemistry |
