• Title/Summary/Keyword: Nanochannel

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Sieving the Polymer Chains through Anodic Aluminum Oxide Membranes (Anodic Aluminum Oxide Membrane을 통한 고분자 사슬의 선택적 투과)

  • Choi, Yong-Joon;Lee, Han Sup
    • Membrane Journal
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    • v.26 no.4
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    • pp.291-300
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    • 2016
  • Techniques for selectively separating molecules of gas and liquid states using various separation membranes have been widely used in variety of applications such as chemical, biological, pharmaceutical, and petrochemical industries. As the nanochannel diameter, inter-channel distance and length of the nanochannel of the anodic aluminum oxide (AAO) membranes can be precisely controlled, various studies to effectively separate mixture of various molecules using AAO membrane have been widely carried out. In this study, we fabricated AAO membranes of cylindrical nanochannels of various diameter sizes and of through-hole structure, that is, nanochannels of which both ends of each nanochannel are open. Using those AAO membranes of through-hole nanochannel structure, we studied the selective permeation polymer chains dissolved in a solvent based on hydraulic volume of the polymer chains. We found a precise, quantitative relationship between the radius of gyration of polymer chains that permeated through nanochannels inside AAO membrane and the diameter of nanochannels. In addition, we demonstrate that the behavior of the polymer solution flowing through nanochannel of the AAO membrane can be successfully described with the Hagen-Poiseuille relationship. It is, therefore, possible to theoretically interpret the nanoflow of the solution flowing inside the cylindrical nanochannel.

Experimental study on effect of nanochannel numbers and working conditions for concentration polarization based desalination process (농도분극현상을 이용한 담수화 과정에서의 나노채널 개수 및 운전조건 영향에 대한 실험 적 연구)

  • Li, Longnan;Kim, Daejoong
    • Journal of the Korean Society of Visualization
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    • v.13 no.2
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    • pp.16-21
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    • 2015
  • Concentration polarization(CP) phenomena show great potential on desalination technology. As we can control the dimension of silicon based nanochannel system, it can be used to model ion exchange membrane. In this study, to investigate the effect of nanochannel number and working conditions on the CP based desalination process, nanochannel based microfluidic system is fabricated. First, we optimized nanochannel number and working conditions to conduct visualization study on CP based desalination process. Second, we visualized the desalination process with fluorescent dye in the desalination chip. We also visualized that the particles also can be removed by the CP based desalination process.

Curve-typed PMMA Nanochannel Fabrication using Polymer Layer Transfer and Collapse Technique (폴리머 층 전사 및 처짐 현상을 이용한 곡선 형태의 PMMA 나노채널 제작)

  • Cho, Young-Hak;Kim, Sung-Dong;Hwang, Ji-Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.1
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    • pp.114-120
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    • 2012
  • We present a simple and low-cost method to fabricate poly(methyl-methacrylate) (PMMA) nanochannels with various shapes by combining the standard optical lithography with a PMMA layer transfer and collapse technique. We utilized PMMA membrane reflowing/collapsing phenomena into microchannels to fabricate nanochannels at both corners of arbitrarily-shaped microchannels. This allows nanochannels with various shapes such as curved nanochannels as well as straight nanochannels to be easily fabricated since the shape of the microchannel determines the shape of the nanochannels. This nanochannel fabrication method is simple, flexible, and low-cost since the standard optical lithography with low-resolution optical masks can be used to fabricate nanoscale channels as small as 100 nm wide with various shapes. Also, the sealing of nanochannels can be naturally achieved while the nanochannels are formed through the polymer layer transfer and collapse.

Field-effect Ion-transport Devices with Carbon Nanotube Channels: Schematics and Simulations

  • Kwon Oh Kuen;Kwon Jun Sik;Hwang Ho Jung;Kang Jeong Won
    • Proceedings of the IEEK Conference
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    • 2004.08c
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    • pp.787-791
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    • 2004
  • We investigated field-effect ion-transport devices based on carbon nanotubes by using classical molecular dynamics simulations under applied external force fields, and we present model schematics that car be applied to the nanoscale data storage devices and unipolar ionic field-effect transistors. As the applied external force field is increased, potassium ions rapidly flow through the nanochannel. Under low external force fields, ther nal fluctuations of the nanochannels affect tunneling of the potassium ions whereas the effects of thermal fluctuations are negligible under high external force fields. Since the electric current conductivity increases when potassium ions are inserted into fullerenes or carbon nanotubes, the field effect due to the gate, which can modify the position of the potassium ions, changes the tunneling current between the drain and the source.

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Simple Fabrication of Micromixer Based on Non-Equilibrium Electrokinetics in Micro/Nano Hybrid Fluidic System (단순공정으로 제작된 마이크로/나노 하이브리드 채널의 불균형 동전기성을 이용한 미세혼합기 연구)

  • Yu, Samuel;Kim, Sun-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.4
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    • pp.385-390
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    • 2011
  • In this study, we developed a micromixer based on the non-equilibrium electrokinetics at the junction of a microchannel and nanochannel. Two fluid streams were mixed by an electro-osmotic flow and a vortex flow created as a result of the non-equilibrium electrokinetics at the junction of the microchannel and nanochannel. Initially, the microchannel was fabricated using Polydimethylsiloxane (PDMS) by the general soft lithography process and the nanochannel was created at a specific position on the microchannel by applying a high voltage. To evaluate the mixing performance of the micromixer, fluorescent distribution was analyzed by using the fluorescent dye, Rhodamine B. About 90% mixing was achieved with this novel micromixer, and this micromixer can be used in microsystems for biochemical sample analysis.

Effects of Surface Roughness and Interface Wettability in a Nanochannel (나노 채널에서의 표면 거칠기와 경계 습윤의 효과)

  • Choo, Yun-Sik;Seo, In-Soo;Lee, Sang-Hwan
    • The KSFM Journal of Fluid Machinery
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    • v.13 no.2
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    • pp.5-11
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    • 2010
  • The nanofluidics is characterized by a large surface-to-volume ratio, so that the surface properties strongly affect the flow resistance. We present here the results showing that the effect of wetting properties and the surface roughness may considerably reduce the friction of fluid past the boundaries. For a simple fluid flowing over hydrophilic and hydrophobic surfaces, the influences of surface roughness are investigated by the nonequilibrium molecular dynamics (NEMD) simulations. The fluid slip at near a solid surface highly depends on the wall-fluid interaction. For hydrophobic surfaces, apparent fluid slips are observed on smooth and rough surfaces. The solid wall is modeled as a rough atomic sinusoidal wall. The effects on the boundary condition of the roughness characteristics are given by the period and amplitude of the sinusoidal wall. It was found that the slip velocity for wetting conditions at interface decreases with increasing effects of surface roughness. The results show the surface rougheness and wettability determines the slip or no-slip boundary conditions. The surface roughness geometry shows significant effects on the boundary conditions at the interface.