title: High-performance, low-voltage electroosmotic pumps with molecularly thin silicon nanomembranes.
abstract: We have developed electroosmotic pumps (EOPs) fabricated from 15-nm-thick porous nanocrystalline silicon (pnc-Si) membranes. Ultrathin pnc-Si membranes enable high electroosmotic flow per unit voltage. We demonstrate that electroosmosis theory compares well with the observed pnc-Si flow rates. We attribute the high flow rates to high electrical fields present across the 15-nm span of the membrane. Surface modifications, such as plasma oxidation or silanization, can influence the electroosmotic flow rates through pnc-Si membranes by alteration of the zeta potential of the material. A prototype EOP that uses pnc-Si membranes and Ag/AgCl electrodes was shown to pump microliter per minute-range flow through a 0.5-mm-diameter capillary tubing with as low as 250 mV of applied voltage. This silicon-based platform enables straightforward integration of low-voltage, on-chip EOPs into portable microfluidic devices with low back pressures.
authors.affiliation: Department of Biochemistry and Biophysics, University of Rochester, Rochester, NY 14642.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Snyder
authors.forename: Jirachai
authors.initials: J
authors.lastname: Getpreecharsawas
authors.forename: David Z
authors.initials: DZ
authors.lastname: Fang
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Gaborski
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Striemer
authors.forename: Philippe M
authors.initials: PM
authors.lastname: Fauchet
authors.forename: David A
authors.initials: DA
authors.lastname: Borkholder
authors.forename: James L
authors.initials: JL
authors.lastname: McGrath
mesh_terms: D004574:Electromagnetic Fields; D056656:Lab-On-A-Chip Devices; D008567:Membranes, Artificial; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods; D049329:Nanostructures / Q000737:chemistry*; D009997:Osmotic Pressure; D012825:Silicon / Q000737:chemistry*
chemical_list: D008567:Membranes, Artificial; D012825:Silicon
keywords: MEMS; electrokinetics; lab-on-a-chip; microfluidics