title: An Alternating Current Electroosmotic Pump Based on Conical Nanopore Membranes.
abstract: Electroosmotic flow (EOF) is used to pump solutions through microfluidic devices and capillary electrophoresis columns. We describe here an EOF pump based on membrane EOF rectification, an electrokinetic phenomenon we recently described. EOF rectification requires membranes with asymmetrically shaped pores, and conical pores in a polymeric membrane were used here. We show here that solution flow through the membrane can be achieved by applying a symmetrical sinusoidal voltage waveform across the membrane. This is possible because the alternating current (AC) carried by ions through the pore is rectified, and we previously showed that rectified currents yield EOF rectification. We have investigated the effect of both the magnitude and frequency of the voltage waveform on flow rate through the membrane, and we have measured the maximum operating pressure. Finally, we show that operating in AC mode offers potential advantages relative to conventional DC-mode EOF pumps.
authors.affiliation: Department of Chemistry, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Chemistry, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Ramiah Rajasekaran
authors.affiliation: Department of Chemistry, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Martin
keywords: AC electroosmotic pump; conical nanopore; electroosmotic flow rectification; high pressure; ion-current rectification; nanofluidic diode