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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

CWE fabrication process.(a) Schematic diagram of CWE fabrication. (b) Scanning electron microscopy (SEM) images of the CWE. The inset shows the individual CNTs. (c) SEM images of the CWE after Au electroplating.
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f2: CWE fabrication process.(a) Schematic diagram of CWE fabrication. (b) Scanning electron microscopy (SEM) images of the CWE. The inset shows the individual CNTs. (c) SEM images of the CWE after Au electroplating.

Mentions: CWEs were fabricated on sharpened TWEs using dielectrophoresis (DEP) and surface tension. A TWE was submerged in a solution, containing CNTs. An AC electric field was applied between the tungsten tube and the TWE (Fig. 2a). The CNTs in the solution were attracted to the TWE by dielectrophoresis (DEP) force. The collected CNTs were compressed by surface tension during solution evaporation. The fabricated CWEs naturally have a tapered architecture, due to the meniscus on the TWE (inset of Fig. 2a). The applied voltage and frequency were controlled to achieve the desired CNW diameter, given the tungsten morphology. The CWE diameter could be increased up to several tens of microns by repeating this process. Figure 2b shows a fabricated CWE; the CWE consisted of many individual CNTs.


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)

CWE fabrication process.(a) Schematic diagram of CWE fabrication. (b) Scanning electron microscopy (SEM) images of the CWE. The inset shows the individual CNTs. (c) SEM images of the CWE after Au electroplating.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: CWE fabrication process.(a) Schematic diagram of CWE fabrication. (b) Scanning electron microscopy (SEM) images of the CWE. The inset shows the individual CNTs. (c) SEM images of the CWE after Au electroplating.
Mentions: CWEs were fabricated on sharpened TWEs using dielectrophoresis (DEP) and surface tension. A TWE was submerged in a solution, containing CNTs. An AC electric field was applied between the tungsten tube and the TWE (Fig. 2a). The CNTs in the solution were attracted to the TWE by dielectrophoresis (DEP) force. The collected CNTs were compressed by surface tension during solution evaporation. The fabricated CWEs naturally have a tapered architecture, due to the meniscus on the TWE (inset of Fig. 2a). The applied voltage and frequency were controlled to achieve the desired CNW diameter, given the tungsten morphology. The CWE diameter could be increased up to several tens of microns by repeating this process. Figure 2b shows a fabricated CWE; the CWE consisted of many individual CNTs.

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