title: Ionic liquid flow along the carbon nanotube with DC electric field.
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'.
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San31, Hyoja-dong, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Jung Hwal
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San31, Hyoja-dong, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Geon Hwee
authors.initials: GH
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San31, Hyoja-dong, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Intae
authors.initials: I
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San31, Hyoja-dong, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Hyungkook
authors.initials: H
authors.lastname: Jeon
authors.affiliation: Department of Mechanical Design Engineering, Andong National University, Andong, Gyungbuk, 760-749, Republic of Korea.
authors.forename: Taechang
authors.initials: T
authors.lastname: An
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San31, Hyoja-dong, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Geunbae
authors.initials: G
authors.lastname: Lim