Low-voltage electroosmotic pumps fabricated from track-etched polymer membranes

Abstract

Track-etched polymer membranes are used to realize low-voltage electroosmotic (EO) pumps. The nanopores in polycarbonate (PC) and polyethylene terephthalate (PET) membranes were fabricated by the track-etching technique, the pore diameter was controlled in the range of 100 to 250 nm by adjusting the etching time. The results show that these EO pumps can provide high flow rates at low applied voltages (2-5 V). The maximum normalized flow rate is as high as 0.12 ml min(-1) V(-1) cm(-2), which is comparable to the best values of previously demonstrated EO pumps. We attribute this high performance to the unique properties of the track-etched nanopores in the membranes.

A large-area, all-plastic, flexible electroosmotic pump

“…6. We measured a maximum limiting hydrostatic pressure of 24.8 ± 1.8 mmH 2 O V −1 or 0.25 kPa V −1 , similar to what Wang et al reported, even though their membranes had approximately double the pore diameter (Wang et al 2012).…”

“…Figure 5 shows the mass flux (calculated per unit membrane area) and the volumetric flow rate versus applied potential as well as the average of the current density measured for each applied potential. The maximum mass flux was measured to be 28 mg min −1 cm −2 , using 1 mM NaCl at 5 V. Similarly arranged measurements using other brands of track-etched polycarbonate membranes are reported to have flow rates (normalized by total cross-sectional pore area) up to 120 µl min −1 cm −2 per volt of applied potential, pumping deionized water (Kwon et al 2012;Wang et al 2012). For our membrane, we estimate a corresponding maximum normalized volumetric flow rate of 50 µl min −1 cm −2 per V of applied potential for 1 mM NaCl, pH 5.6, similar to that reported for a polycarbonate membrane in 1 mM borate buffer at pH 9 (Kwon et al 2012).…”

“…The sub-mm thickness of these membranes results in a strong electric field (range 100-250 kV m −1 ), even when small potentials (2-5 V) are applied, resulting in significant flow even at potentials that are small enough to be supplied by, for example, standard AA batteries and used safely in consumer products. Several groups have previously shown that membranes of polycarbonate (PC), polyethylene terephthalate (PET), and nylon can be incorporated in EOPs (Kwon et al 2012;Wang et al 2012;Wu et al 2016). PC membranes reportedly generate volumetric flow rates up to 120 µl min −1 per cm 2 of membrane area and V of applied potential (Eidsnes et al 2004;Kwon et al 2012; (…”

Electroosmotic Flow Pump

“…The open capillary has the ability to deliver a wide range of sample reagents such as pure liquid drug reagents and aqueous solutions containing cells, particles, or biochemical macromolecules. The porous media EOF pumps [25][26][27][28][29][30][31][32] can also be used to drive pure liquid sample reagents for the injection purpose. For on-chip microfluidic delivery, open-channel EOF pumps [20][21][22][23][24] are the most popular pumping devices.…”

“…Porous membrane EOF pumps [25][26][27][28] utilize a piece of porous membrane to construct submicroscale or nanoscale pump channels within. They are miniaturized and highly integrated microfluidic pumping devices.…”