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Rapid Particle Patterning in Surface Deposited Micro-Droplets of Low Ionic Content via Low-Voltage Electrochemistry and Electrokinetics.

Sidelman N, Cohen M, Kolbe A, Zalevsky Z, Herrman A, Richter S - Sci Rep (2015)

Bottom Line: However, the use of DC-induced electrokinetics in miniaturized devices is highly limited.We show that this is made possible in low ion content dispersions, which enable low-voltage electrokinetics and an anomalous bubble-free water electrolysis.This phenomenon can serve as a powerful tool in both microflow devices and digital microfluidics for rapid pre-concentration and particle patterning.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering Faculty of Engineering &University Center for Nano Science and Nanotechnology Tel Aviv University, Tel-Aviv, 69978, Israel.

ABSTRACT
Electrokinetic phenomena are a powerful tool used in various scientific and technological applications for the manipulation of aqueous solutions and the chemical entities within them. However, the use of DC-induced electrokinetics in miniaturized devices is highly limited. This is mainly due to unavoidable electrochemical reactions at the electrodes, which hinder successful manipulation. Here we present experimental evidence that on-chip DC manipulation of particles between closely positioned electrodes inside micro-droplets can be successfully achieved, and at low voltages. We show that such manipulation, which is considered practically impossible, can be used to rapidly concentrate and pattern particles in 2D shapes in inter-electrode locations. We show that this is made possible in low ion content dispersions, which enable low-voltage electrokinetics and an anomalous bubble-free water electrolysis. This phenomenon can serve as a powerful tool in both microflow devices and digital microfluidics for rapid pre-concentration and particle patterning.

No MeSH data available.


Numerical simulation of pH zones shape based on electrostatics at charge ratio of 11.7 (see text).The acidic zone is colored in yellow and the basic zone in green. Arbitrary voltages of (a) 1.5 V and (b) 2.0 V show the change in the zones shape as a function of field strength. See text.
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f5: Numerical simulation of pH zones shape based on electrostatics at charge ratio of 11.7 (see text).The acidic zone is colored in yellow and the basic zone in green. Arbitrary voltages of (a) 1.5 V and (b) 2.0 V show the change in the zones shape as a function of field strength. See text.

Mentions: Figure 5 shows the result of such a simulation performed for the case of the TiO2 dispersion previously described. It was obtained by a 3D numerical solution of Poisson’s equation out of which we extracted the 2D solution for the substrate plane (see SI data 1). A value was assigned to positive and negative test charges. The test charges were then “released” at the respective electrodes, and their movement was examined.


Rapid Particle Patterning in Surface Deposited Micro-Droplets of Low Ionic Content via Low-Voltage Electrochemistry and Electrokinetics.

Sidelman N, Cohen M, Kolbe A, Zalevsky Z, Herrman A, Richter S - Sci Rep (2015)

Numerical simulation of pH zones shape based on electrostatics at charge ratio of 11.7 (see text).The acidic zone is colored in yellow and the basic zone in green. Arbitrary voltages of (a) 1.5 V and (b) 2.0 V show the change in the zones shape as a function of field strength. See text.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543935&req=5

f5: Numerical simulation of pH zones shape based on electrostatics at charge ratio of 11.7 (see text).The acidic zone is colored in yellow and the basic zone in green. Arbitrary voltages of (a) 1.5 V and (b) 2.0 V show the change in the zones shape as a function of field strength. See text.
Mentions: Figure 5 shows the result of such a simulation performed for the case of the TiO2 dispersion previously described. It was obtained by a 3D numerical solution of Poisson’s equation out of which we extracted the 2D solution for the substrate plane (see SI data 1). A value was assigned to positive and negative test charges. The test charges were then “released” at the respective electrodes, and their movement was examined.

Bottom Line: However, the use of DC-induced electrokinetics in miniaturized devices is highly limited.We show that this is made possible in low ion content dispersions, which enable low-voltage electrokinetics and an anomalous bubble-free water electrolysis.This phenomenon can serve as a powerful tool in both microflow devices and digital microfluidics for rapid pre-concentration and particle patterning.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering Faculty of Engineering &University Center for Nano Science and Nanotechnology Tel Aviv University, Tel-Aviv, 69978, Israel.

ABSTRACT
Electrokinetic phenomena are a powerful tool used in various scientific and technological applications for the manipulation of aqueous solutions and the chemical entities within them. However, the use of DC-induced electrokinetics in miniaturized devices is highly limited. This is mainly due to unavoidable electrochemical reactions at the electrodes, which hinder successful manipulation. Here we present experimental evidence that on-chip DC manipulation of particles between closely positioned electrodes inside micro-droplets can be successfully achieved, and at low voltages. We show that such manipulation, which is considered practically impossible, can be used to rapidly concentrate and pattern particles in 2D shapes in inter-electrode locations. We show that this is made possible in low ion content dispersions, which enable low-voltage electrokinetics and an anomalous bubble-free water electrolysis. This phenomenon can serve as a powerful tool in both microflow devices and digital microfluidics for rapid pre-concentration and particle patterning.

No MeSH data available.