title: Electrostatic potential wells for on-demand drop manipulation in microchannels.
abstract: Precise control and manipulation of individual drops are crucial in many lab-on-a-chip applications. We present a novel hybrid concept for channel-based discrete microfluidics with integrated electrowetting functionality by incorporating co-planar electrodes (separated by a narrow gap) in one of the microchannel walls. By combining the high throughput of channel-based microfluidics with the individual drop control achieved using electrical actuation, we acquire the strengths of both worlds. The tunable strength of the electrostatic forces enables a wide range of drop manipulations, such as on-demand trapping and release, guiding, and sorting of drops in the microchannel. In each of these scenarios, the retaining electrostatic force competes with the hydrodynamic drag force. The conditions for trapping can be predicted using a simple model that balances these forces.
authors.affiliation: Physics of Complex Fluids and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. r.deruiter-1@utwente.nl.
authors.forename: Riëlle
authors.initials: R
authors.lastname: de Ruiter
authors.forename: Arjen M
authors.initials: AM
authors.lastname: Pit
authors.forename: Vitor Martins
authors.initials: VM
authors.lastname: de Oliveira
authors.forename: Michèl H G
authors.initials: MH
authors.lastname: Duits
authors.forename: Dirk
authors.initials: D
authors.lastname: van den Ende
authors.forename: Frieder
authors.initials: F
authors.lastname: Mugele
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004566:Electrodes; D058874:Electrowetting; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D008962:Models, Theoretical; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D004129:Dimethylpolysiloxanes; D014867:Water; C013830:baysilon