Evaluation of electroosmosis and streaming potential for measurement of electric charges of polymeric membranes

Kim, K.J.; Fane, A.G.; Nyström, Marianne; Pihlajamäki, Arto; Bowen, W. Richard; Mukhtar, Hilmi

doi:10.1016/0376-7388(96)00038-5

Cited by 148 publications

(49 citation statements)

References 18 publications

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“…Streaming potential measurements are the most common form of zeta potential calculation, although we include electroosmotic calculations for comparison. pH changes induced by electrolysis at the electrodes and the effects of ion migration through the device can influence the zeta potential as calculated from electroosmosis (33). We do see an agreement in the trend of the zeta potentials as calculated by the different methods for the treated membranes, although electroosmosis calculations lead to lower zeta potentials for all membrane types.…”

Section: Significancesupporting

confidence: 55%

High-performance, low-voltage electroosmotic pumps with molecularly thin silicon nanomembranes

Snyder

Getpreecharsawas

Fang

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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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.lectroosmotic flow results from the interaction between an electric field and the diffuse layer of ions at a charged surface. In capillaries or pores, the migration of the diffuse layer toward the oppositely charged electrode causes the bulk fluid within the channel to flow through viscous drag. Electroosmotic pumps (EOPs) are designed to generate high flow rates in microchannels using these principles (1, 2). EOPs present a number of advantages over mechanical pumps, including the lack of mechanical parts, pulse-free flows, and ease of control through electrode actuation. EOPs have been suggested as pumps for cooling circuits (3) and microfluidic devices that aid in drug delivery (4, 5) or diagnostics (2, 6). Microfluidic devices enable the miniaturization of multistep laboratory processes into small, low-cost, disposable units (6, 7). The inclusion of multiple steps into a single device increases the need for the precision pumping of fluids on-chip.High voltages (>1 kV) are often required for direct current (dc) EOPs to achieve sufficient flow rates in microchannels (8, 9). However, devices with high-voltage EOPs require bulky external power supplies and a skilled technician to operate, which defeats the ease of use and portability aims of a microfluidic diagnostic tool. For these reasons, the development of a low-voltage EOP is a current focus in the literature. Several recent low-voltage EOPs have been fabricated from porous silicon (10), alumina (11-13), track-etched polymer (14), and carbon nanotube membranes (15). These low-voltage EOPs are much thinner than their highvoltage predecessors (60-350 μm compared with >10 mm). Yao et al. suggest that further thinning of EOPs will enable better voltage-specific characteristics (16). Here, we examine the electroosmotic pumping by nanoporous membranes that are more than two orders of magnitude thinner than any membrane material previously used in an EOP.We have recently developed an ultrathin (15-30 nm), nanoporous membrane material called porous nanocrystalline silicon (pnc-Si) (17). pnc-Si membranes are fabricated on silicon wafers usin...

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Section: Significancesupporting

confidence: 55%

High-performance, low-voltage electroosmotic pumps with molecularly thin silicon nanomembranes

Snyder

Getpreecharsawas

Fang

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…Speci®c ionic adsorption is the only process possible for surface charge formation of the PSU samples as PSU has no dissociable functional groups. The magnitude of the zeta potentials obtained for this material by the tangential¯ow technique is somewhat larger than values obtained by others from perpendicular¯ow streaming potential measurements of commercial polysulfone UF membranes [9,17]. As mentioned above, the in¯uence of small pores is most likely responsible for this behavior and leads to an underestimation of the true zeta potential of the surface.…”

Section: Resultsmentioning

confidence: 60%

“…In the case of¯at surfaces such as polymeric membranes, electroosmosis and streaming potential measurements are most appropriate for studying a stationary solid phase and a mobile liquid phase. Measuring streaming potentials is the most practical and convenient technique for¯at surfaces or porous membranes, and superior to electroosmosis [9].…”

Section: Electrokinetic Theorymentioning

confidence: 99%

Tangential flow streaming potential measurements: Hydrodynamic cell characterization and zeta potentials of carboxylated polysulfone membranes

Möckel¹,

Staude²,

Dal‐Cin

et al. 1998

Journal of Membrane Science

152

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Computational¯uid dynamics calculations were carried out to ensure that a self-made tangential¯ow mode streaming potential measurement cell meets the hydrodynamic stipulations of laminar, steady and established electrolyte¯ow necessary for reproducible electrokinetic measurements. The calculations show that the cell design meets all of these conditions.Six carboxylated polysulfones with a range of different degrees of substitution (DS) from 0.26 to 1.74 carboxyl groups per polymer repeat unit were synthesized in a two-stage process of lithiation and carboxylation. Ultra®ltration membranes were made from both the unmodi®ed polysulfone and these hydrophilic materials. The zeta potentials of these membrane surfaces were determined in 0.001 M KCl solution as a function of pH. The curves show the theoretically expected pro®les for nonionic and weakly acidic materials. The growing in¯uence of the COOH dissociation on the surface charge formation is indicated by the¯attening of the curves at low pH values. The magnitude of the negative zeta potentials plateau values ranged from À52 to À20 mV. While unmodi®ed PSU has a plateau value of À52 mV this value decreases continuously with increasing DS to À20 mV for the PSU-COOH 1.74 material. It is suggested that this arises from a shift of the electrokinetic shear plane into the bulk electrolyte solution due to an extended swelling layer re¯ecting the enhanced hydrophilicity of these membrane surfaces. # 1998 Elsevier Science B.V.

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“…This relationship is commonly used to calculate membrane zeta potential from experimental variations of the electro-osmotic flux versus the current density [18,19].…”

Section: Transport Phenomenamentioning

confidence: 99%

Study of the mass transfer phenomena involved in an electrophoretic membrane contactor

Galier

Balmann

2001

Journal of Membrane Science

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Electrophoretic separators, in which a porous membrane is used as a contactor, offer the possibility to scale up electrophoresis as well as to extend the field of application of electrodialysis to fractionate polyamino acids, peptides or small proteins for instance. This paper deals with the study of the mass transfer mechanisms involved in such electroseparation processes. On one hand, a theoretical approach is carried out. The different contributions to the mass transfer are considered in order to establish a relationship providing the solute concentration as function of the main parameters of the system, i.e. the operating conditions and the membrane, buffer and solute characteristics. In this expression, a partition coefficient is used to represent the interactions taking place at the membrane-solution interface. Then, an experimental study is performed with different representative solutes using a prototype apparatus in order to determine the dependence of the solvent and solute transfer with respect to the operating and physicochemical parameters of the system. The experimental results show the existence of a limiting electro-osmotic flux, the origin of which is explained. Then the partition coefficient is determined for any set of conditions by fitting the variations of the solute concentration calculated by the model with experimental ones. The dependence of the partition coefficient with respect to the solute and buffer characteristics, together with that of the transmission coefficient obtained during filtration experiments, shows that the main limitation with respect to the mass transfer is due to electrostatic interactions taking place at the membrane-solution interface.

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Evaluation of electroosmosis and streaming potential for measurement of electric charges of polymeric membranes

Cited by 148 publications

References 18 publications

High-performance, low-voltage electroosmotic pumps with molecularly thin silicon nanomembranes

High-performance, low-voltage electroosmotic pumps with molecularly thin silicon nanomembranes

Tangential flow streaming potential measurements: Hydrodynamic cell characterization and zeta potentials of carboxylated polysulfone membranes

Study of the mass transfer phenomena involved in an electrophoretic membrane contactor

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