PHYSICAL MATHEMATICS SEMINAR TOPIC: ELECTOPHORESIS OF CONDUCTORS: THEORY AND MICROFLUIDIC APPLICATIONS SPEAKER: MARTIN BAZANT Department of Mathematics Massachusetts Institute of Technology Abstract: When a background electric field is applied to a conductor immersed in a liquid electrolyte, its surface charge evolves to produce a nonuniform zeta potential, and the resulting electro-osmotic flow is very different from the familiar case of an insulator (with a fixed zeta potential). As the electric field increases, it is predicted that a charged, conducting sphere reaches a limiting electrophoretic velocity (i.e. its mobility vanishes), and a secondary flow develops, which sucks in fluid along the field axis and ejects it radially. In this talk, a simple physical picture of such intriguing phenomena will be presented, and a variety of microfluidic applications will be discussed, such as micro-pumps and mixers driven by AC electric fields. [Joint work with Todd Squires (Department of Physics, Harvard University).] DATE: TUESDAY, NOVEMBER 6, 2001 TIME: 2:30 PM LOCATION: Building 2, Room 338 Refreshments will be served at 3:30 PM in Room 2-349 Massachusetts Institute of Technology Department of Mathematics Cambridge, MA 02139