• Title/Summary/Keyword: soft lithographic method

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Solvent-Assisted Soft-Lithographic Patterning of Lyotropic Liquid Crystalline Polymer Film by Flow Control through Patterned Channels

  • Park, Chang-Sub;Park, Kyung-Woo;Kang, Shin-Won;Kwak, Gi-Seop;Kim, Hak-Rin
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.641-644
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    • 2009
  • We demonstrated a solvent-assisted soft-lithographic patterning method for producing patterned structure and patterned ordering with lyotropic liquid crystalline polymer (LCP) film. Experimental results showed that the liquid crystalline ordering of lyotropic film could be controlled by shearing effects of the fluidic solvent though the patterned mold channels. In this work, two types of lyotropic LCPs were used to investigate the effects of the alkyl chain length of the lyotropic LCP on producing liquid crystalline ordering through the solvent-assisted fluidic patterning.

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Effects of External Voltages and Widths on Fluid Velocity in Microchannel (외부전압 및 너비 변화에 따른 마이크로채널의 유체 속도 변화)

  • Kim, Jin-Yong;Lee, Hyo-Song;Kim, Jeong-Soo;Rhee, Young Woo
    • Applied Chemistry for Engineering
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    • v.16 no.2
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    • pp.238-242
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    • 2005
  • In this work, Polydimethylsiloxane (PDMS) and SU-8 (Microchem, USA) photoresist were used to make the microchannel by soft lithographic method. To investigate the effects of external voltages and widths of the microchannel, we made the microchannel by soft lithographic method. To investigate the effects of external voltages and widths of the microchannel, we made the microchannel with various widths: $100{\mu}m,\;200{\mu}m$ and $300{\mu}m$. And each micorchannel was supplied with external voltage, respectively. As a result, the fluid velocity increased with an increase of the external voltage at the same width. It was speculated that the electrical double layer was condensed and the zeta potential increased with increase of the external voltage. The fluid velocity increased with the microchannel width increase at the same external voltage. It is concluded that the resistance in the microchannel decreased as the microchannel width increased.

Soft Lithography of Graphene Sheets Via Surface Energy Modification

  • Kim, Hansun;Jung, Min Wook;Myung, Sung;Jung, Daesung;Lee, Sun Sook;Kong, Ki-Jeong;Lim, Jongsun;Lee, Jong-Heun;Park, Chong Yun;An, Ki-Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.144.2-144.2
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    • 2013
  • With the synthesis of graphene sheets as large-scale and high quality, it is essentially important to develop suitable graphene patterning process for future industrial applications. Especially, transfer or patterning method of CVD-grown graphene has been studied. We report simple soft lithographic process to develop easily applicable patterning method of large-scale graphene sheets by using chemically functionalized polymer stamp. Also important applications, the prototype capacitors with graphene electrode and commercial polymer dielectrics for the electrostatic-type touch panel are fabricated using the developed soft lithographic patterning and transfer process.

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Soft Lithographic Patterning Method for Flexible Graphene-based Chemical Sensors with Heaters

  • Kang, Min-a;Jung, Min Wook;Myung, Sung;Song, Wooseok;Lee, Sun Suk;Lim, Jongsun;Park, Chong-Yun;An, Ki-Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.176.2-176.2
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    • 2014
  • In this work, we demonstrated that the fabrication of flexible graphene-based chemical sensor with heaters by soft lithographic patterning method [1]. First, monolayer and multilayer graphene were prepared by thermal chemical vapor deposition transferred onto SiO2 / Si substrate in order to fabrication of patterned-sensor and -heater. Second, patterned-monolayer and multilayer graphene were detached through soft lithography process, which was transferred on top and bottom sides of PET film. Third, Au / Ti (Thickness : 100/30 nm) electrodes were deposited end of the patterned-graphene line by sputtering system. Finally, we measured sensor properties through injection of NO2 and CO2 gas on different temperature with voltage change of graphene heater.

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Fabrication of Graphene-based Flexible Devices Utilizing Soft Lithographic Patterning Method

  • Jung, Min Wook;Myung, Sung;Kim, Kiwoong;Jo, You-Young;Lee, Sun Suk;Lim, Jongsun;Park, Chong-Yun;An, Ki-Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.165-165
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    • 2014
  • In this study, we demonstrated that the soft lithographic patterning processing of chemical vapor deposition (CVD) graphene and rGO sheets as large scale, low cost, high quality and simplicity for future industrial applications. Recently, a previous study has reported that single layer graphene grown via CVD was patterned and transferred to a target surface by controlling the surface energy of the polydimethylsiloxane (PDMS) stamp [1]. Using this approach, the surface of a relief-patterned elastomeric stamp was functionalized with hydrophilic dimethylsulfoxide (DMSO) molecules to enhance the surface energy of the stamp and to remove the graphene-based layer from the initial substrate and transfer it to a target surface [2]. Further, we developed a soft lithographic patterning process via surface energy modification for advanced graphene-based flexible devices such as transistors or simple and efficient chemical sensor consisting of reduced graphene oxide (rGO) and a metallic nanoparticle composite. A flexible graphene-based device on a biocompatible silk fibroin substrate, which is attachable to an arbitrary target surface, was also successfully fabricated.

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Variation of Flow Rates in Heterogeneous Microchannel Systems (비균일계 마이크로채널에서의 유량 변화 특성)

  • Kim, Jin-Yong;Lee, Hyo-Song;Yu, Jae-Keun;Kim, Ki-Ho;Rhee, Young Woo
    • Applied Chemistry for Engineering
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    • v.17 no.1
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    • pp.28-32
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    • 2006
  • This study investigated the variation of flow rates in microchannels that consisted of polydimethyl siloxane (PDMS) and glass using various external voltages. Three different microchannel widths and two different depths. PDMS and negative photoresist (SU-8) were used to make the microchannels by the soft lithographic method. For each depth of microchannel ($50{\mu}m$ and $100{\mu}m$), three different widths ($100{\mu}m$, $200{\mu}m$ and $300{\mu}m$) were made. In each case, several different external voltages were applied (0.3 kV, 0.35 kV, 0.4 kV and 0.45 kV) to examine the flow rates. Our results indicated that flow rate increased with an increase of the external voltage at the same microchannel width. This was because the electrical field was increased as the external voltage increased. For the same external voltage, the flow rate increased as the microchannel's width increased. These results showed that the resistance in the microchannel decreased as the microchannel's width increased. Also, to investigate the effect of microchannel's depth and width, the cross-sectional area of the microchannel was increased to the double in area. As a result, the effect of the microchannel's depth was higher at a low external voltage, and the effect of the microchannel's width was higher at a high external voltage.

Surface modification method for controlling liquid crystal alignment

  • Kim, Hak-Rin;Song, June-Yong;Bae, Kwang-Soo;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.299-302
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    • 2007
  • We propose a soft-lithographic patterning method for producing a multi-domain liquid crystal (LC) alignment. The LC alignment polyimide layers are periodically patterned in the pixel boundaries by a micromolding-in-capillaries method. In our structure, the initially homeotropic LC orientations in the pixel areas are changed to axially symmetric LC domains due to the symmetric pretilt of LC molecules on the pixel boundaries.

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Patterning of liquid crystal alignment layers using selective dewetting process in a thermoplastic polymer film

  • Kim, Hak-Rin;Shin, Min-Soo;Lee, You-Jin;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1719-1722
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    • 2006
  • We proposed a soft-lithographic method for aligning a liquid crystal (LC) in patterned azimuthal orientations. It is demonstrated that a thermoplastic polystyrene layer is patterned from a thermally stable polyimide layer via pressure-assisted capillary force lithography, which provides multidirectional LC alignment condition simply followed by a unidirectional rubbing process.

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Design of a specimen holder for living cell in the soft X-ray microscopy (연 X-선 현미경을 위한 생체시료 고정장치 설계)

  • 권영만;김경우;윤권하
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.705-708
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    • 2003
  • To observe a hydrated biological specimen, an environmental chamber was necessary to keep the specimen in a wet state under vacuum surroundings. The specimen holder is as follows designed consequently. The specimen holder consisted of two Si wafers, the centers of which were Si$_3$N$_4$(100nm thickness) windows of a 0.3mm square. The windows were made by a photo-lithographic method. The transmission of a window at 400eV is about 70%. A hydrated biological specimen was put between the two windows. When the chamber was closed, two wafers were contact at the metal mesh by the pressure of O-rings, and the specimen holder moved by the three micrometers.

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