Transient behavior of an electrolytic diode

Slouka, Zdeněk; Přibyl, Michal; Šnita, Dalimil; Postler, Tomáš

doi:10.1039/b707197c

Cited by 20 publications

(12 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mathematical model is based on the approach used in works. 27,28 The velocity v and pressure p fields are described by the Stokes equation 29 ͑Reynolds number is close to zero͒ containing the coulomb force term and by the continuity equation for an incompressible Newtonian fluid…”

Section: -5mentioning

confidence: 99%

Study on surface properties of PDMS microfluidic chips treated with albumin

Schrott¹,

Slouka²,

Červenka³

et al. 2009

Biomicrofluidics

Self Cite

View full text Add to dashboard Cite

Electrokinetic properties and morphology of PDMS microfluidic chips intended for bioassays are studied. The chips are fabricated by a casting method followed by polymerization bonding. Microchannels are coated with 1% solution of bovine serum albumin ͑BSA͒ in Tris buffer. Albumin passively adsorbs on the PDMS surface. Electrokinetic characteristics ͑electro-osmotic velocity, electro-osmotic mobility, and zeta potential͒ of the coated PDMS channels are experimentally determined as functions of the electric field strength and the characteristic electrolyte concentration. Atomic force microscopy ͑AFM͒ analysis of the surface reveals a "peak and ridge" structure of the protein layer and an imperfect substrate coating. On the basis of the AFM observation, several topologies of the BSA-PDMS surface are proposed. A nonslip mathematical model of the electro-osmotic flow is then numerically analyzed. It is found that the electrokinetic characteristics computed for a channel with the homogeneous distribution of a fixed electric charge do not fit the experimental data. Heterogeneous distribution of the fixed electric charge and the surface roughness is thus taken into account. When a flat PDMS surface with electric charge heterogeneities is considered, the numerical results are in very good agreement with our experimental data. An optimization analysis finally allowed the determination of the surface concentration of the electric charge and the degree of the PDMS surface coating. The obtained findings can be important for correct prediction and possibly for robust control of behavior of electrically driven PDMS microfluidic chips. The proposed method of the electro-osmotic flow analysis at surfaces with a heterogeneous distribution of the surface electric charge can also be exploited in the interpretation of experimental studies dealing with protein-solid phase interactions or substrate coatings.

show abstract

Section: -5mentioning

confidence: 99%

Study on surface properties of PDMS microfluidic chips treated with albumin

Schrott¹,

Slouka²,

Červenka³

et al. 2009

Biomicrofluidics

Self Cite

View full text Add to dashboard Cite

show abstract

“…While the rectification effect of microfluidic bipolar membranes or nanofluidic devices has been widely studied, [10][11][12][13][14] its water splitting effect has yet to be explored and exploited in microfluidics. The DC current-voltage (I-V) curve exhibits high ionic conductance at forward polarization when the cathode connects to the anion exchange membrane and high resistance at small reverse bias followed by low resistance due to electric field-enhanced water dissociation that generates additional ions at large a) Author to whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Microscale pH regulation by splitting water

2011

View full text Add to dashboard Cite

We present a simple, flexible approach for pH regulation in micro-chambers by injecting controllable amounts of protons and hydroxide ions via field-enhanced dissociation of water molecules. Under a DC voltage bias, the polymeric bipolar membranes integrated in microfluidics devices generate and separate H þ and OH À ions without gas production or contaminant generation resulting from electron-transfer reactions. Robust local on-chip pH and pH gradients are sustained with no need of additional acidic/basic solutions that dilute analyte concentrations. The method could provide a better strategy for pH control in microfluidics.

show abstract

“…Diodes are attractive due to their rectification property and they can be used in simple logic gate 45 circuits and also as the addressing element in cross-point matrix systems. Several different types of ion diodes have previously been reported, based on either nanofluidic channels [23][24][25] , hydrogels [26][27][28][29] , or BMs [30][31][32] . Nanofluidic diodes exhibit ion current rectification due to surface charges along nanometer-sized 50 channels, which offer selective ion transport.…”

Section: Introductionmentioning

confidence: 99%

“…operation at 55 physiological conditions. Electrolytic diodes consist of a hydrogel which separates an acidic and an alkali solution 26,27 In forward bias the conjugated base and acid migrates through the hydrogel, while in reverse bias the conductivity is reduced due to H + and OH -recombination. Although potent as a diode, the acidic/alkali 60 electrolytes impose limitations for possible applications.…”

Section: Introductionmentioning

confidence: 99%

Ion diode logics for pH control

2012

View full text Add to dashboard Cite

Electronic control over the generation, transport, and delivery of ions is useful in order to regulate reactions, functions, and processes in 5 various chemical and biological systems. Different kinds of ion diodes and transistors that exhibit non-linear current versus voltage characteristics have been explored to generate chemical gradients and signals. Bipolar membranes (BMs) exhibit both ion current rectification and water splitting and are thus suitable as ion diodes for the regulation of pH. To date, fast switching ion diodes have been difficult to realize due to accumulation of ions inside the device structure at forward bias -charges that take a long time to deplete at reverse bias. Water splitting occurs at elevated reverse voltage bias and is a feature that renders high ion current rectification impossible. 10This makes integration of ion diodes in circuits difficult. Here, we report three different designs of micro-fabricated ion bipolar membrane diodes (IBMDs). The first two designs consist of single BM configurations, and are capable of either splitting water or providing high current rectification. In the third design, water-splitting BMs and a highly-rectifying BM are connected in series, thus suppressing accumulation of ions. The resulting IBMD shows less hysteresis, faster off-switching, and also a high ion current rectification ratio as compared to the single BM devices. Further, the IBMD was integrated in a diode-based AND gate, which is capable 15 of controlling delivery of a hydroxide ions into a receiving reservoir.

show abstract

Transient behavior of an electrolytic diode

Cited by 20 publications

References 17 publications

Study on surface properties of PDMS microfluidic chips treated with albumin

Study on surface properties of PDMS microfluidic chips treated with albumin

Microscale pH regulation by splitting water

Ion diode logics for pH control

Contact Info

Product

Resources

About