We report observations of new many-body phenomena in the micro-scale behavior of a suspension subject to a high-gradient strong alternating current (ac) field and shear. Their origin is dielectrophoresis accompanied by the field-induced phase separation in a flowing suspension. We present a model for the coupling of shear, ac dielectrophoresis, and phase separation, whose predictions are consistent with the evolution of the particle patterns observed in our experiments. We also demonstrate that ac dielectrophoresis accompanied by a field-induced phase separation constitutes a powerful method for concentrating particles in focused regions of electro-microfluidics and for separating biological and non-biological materials.
Journal: TechConnect Briefs
Volume: 2, Technical Proceedings of the 2004 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: March 7, 2004
Pages: 367 - 370
Industry sector: Sensors, MEMS, Electronics
Topics: MEMS & NEMS Devices, Modeling & Applications