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Ionic liquid flow along the carbon nanotube with DC electric field.

Shin JH, Kim GH, Kim I, Jeon H, An T, Lim G - Sci Rep (2015)

Bottom Line: For biological applications, a better understanding of the ionic solution pumping mechanism is required.The resulting electro-osmotic flow was attributed to the movement of an electric double layer near the electrode, and the flow rates along the CWEs were on the order of picoliters per minute.We classified into three pumping zones, according to the initiating voltage and faradaic reaction.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San31, Hyoja-dong, Pohang, Gyungbuk, 790-784, Republic of Korea.

ABSTRACT
Liquid pumping can occur along the outer surface of an electrode under a DC electric field. For biological applications, a better understanding of the ionic solution pumping mechanism is required. Here, we fabricated CNT wire electrodes (CWEs) and tungsten wire electrodes (TWEs) of various diameters to assess an ionic solution pumping. A DC electric field created by a bias of several volts pumped the ionic solution in the direction of the negatively biased electrode. The resulting electro-osmotic flow was attributed to the movement of an electric double layer near the electrode, and the flow rates along the CWEs were on the order of picoliters per minute. According to electric field analysis, the z-directional electric field around the meniscus of the small electrode was more concentrated than that of the larger electrode. Thus, the pumping effect increased as the electrode diameter decreased. Interestingly in CWEs, the initiating voltage for liquid pumping did not change with increasing diameter, up to 20 μm. We classified into three pumping zones, according to the initiating voltage and faradaic reaction. Liquid pumping using the CWEs could provide a new method for biological studies with adoptable flow rates and a larger 'Recommended pumping zone'.

No MeSH data available.


Related in: MedlinePlus

Liquid pumping of an ionic solution along a CWE.(a) Schematic diagram of the ionic solution transport along the CWE. (b) Optical time-lapse images of the ionic solution transported along the CWE over 20 sec period.
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f3: Liquid pumping of an ionic solution along a CWE.(a) Schematic diagram of the ionic solution transport along the CWE. (b) Optical time-lapse images of the ionic solution transported along the CWE over 20 sec period.

Mentions: The CWE was manipulated by a three-axis stage and placed into an ionic solution droplet. A KCl ionic solution was used in this study because K+ and Cl– ions have similar electric mobility. Figure 3a shows that the liquid transported liquid along the CWE when a DC electric field was applied; note that the thin liquid ‘precursor film’ was excluded. When the CWE was submerged, a meniscus formed along the CWE. Without an external force, the liquid spread along the CWE due to its tapered architecture and hydrophilic characteristics. This phenomenon is described in detail in Figure S1. A negative bias was applied to the CWE, resulting in pumping of the liquid along the CWE surface. During liquid pumping, some of the collected liquid generated beads along the CWE. If a DC voltage was applied between the two electrodes continuously, then the liquid flowed continuously along the CWE.


Ionic liquid flow along the carbon nanotube with DC electric field.

Shin JH, Kim GH, Kim I, Jeon H, An T, Lim G - Sci Rep (2015)

Liquid pumping of an ionic solution along a CWE.(a) Schematic diagram of the ionic solution transport along the CWE. (b) Optical time-lapse images of the ionic solution transported along the CWE over 20 sec period.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488867&req=5

f3: Liquid pumping of an ionic solution along a CWE.(a) Schematic diagram of the ionic solution transport along the CWE. (b) Optical time-lapse images of the ionic solution transported along the CWE over 20 sec period.
Mentions: The CWE was manipulated by a three-axis stage and placed into an ionic solution droplet. A KCl ionic solution was used in this study because K+ and Cl– ions have similar electric mobility. Figure 3a shows that the liquid transported liquid along the CWE when a DC electric field was applied; note that the thin liquid ‘precursor film’ was excluded. When the CWE was submerged, a meniscus formed along the CWE. Without an external force, the liquid spread along the CWE due to its tapered architecture and hydrophilic characteristics. This phenomenon is described in detail in Figure S1. A negative bias was applied to the CWE, resulting in pumping of the liquid along the CWE surface. During liquid pumping, some of the collected liquid generated beads along the CWE. If a DC voltage was applied between the two electrodes continuously, then the liquid flowed continuously along the CWE.

Bottom Line: For biological applications, a better understanding of the ionic solution pumping mechanism is required.The resulting electro-osmotic flow was attributed to the movement of an electric double layer near the electrode, and the flow rates along the CWEs were on the order of picoliters per minute.We classified into three pumping zones, according to the initiating voltage and faradaic reaction.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San31, Hyoja-dong, Pohang, Gyungbuk, 790-784, Republic of Korea.

ABSTRACT
Liquid pumping can occur along the outer surface of an electrode under a DC electric field. For biological applications, a better understanding of the ionic solution pumping mechanism is required. Here, we fabricated CNT wire electrodes (CWEs) and tungsten wire electrodes (TWEs) of various diameters to assess an ionic solution pumping. A DC electric field created by a bias of several volts pumped the ionic solution in the direction of the negatively biased electrode. The resulting electro-osmotic flow was attributed to the movement of an electric double layer near the electrode, and the flow rates along the CWEs were on the order of picoliters per minute. According to electric field analysis, the z-directional electric field around the meniscus of the small electrode was more concentrated than that of the larger electrode. Thus, the pumping effect increased as the electrode diameter decreased. Interestingly in CWEs, the initiating voltage for liquid pumping did not change with increasing diameter, up to 20 μm. We classified into three pumping zones, according to the initiating voltage and faradaic reaction. Liquid pumping using the CWEs could provide a new method for biological studies with adoptable flow rates and a larger 'Recommended pumping zone'.

No MeSH data available.


Related in: MedlinePlus