• Title, Summary, Keyword: Polyimid

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Effects of Poly(Styrene-Co-Maleic acid) as Adhesion Promoter on Rheology of Aqueous Cu Nanoparticle Ink and Adhesion of Printed Cu Pattern on Polyimid Film (수계 Cu 나노입자 잉크에서 Poly(styrene-co-maleic acid) 접착 증진제가 잉크 레올로지와 인쇄패턴의 접착력에 미치는 영향)

  • Jo, Yejin;Seo, Yeong-Hui;Jeong, Sunho;Choi, Youngmin;Kim, Eui Duk;Oh, Seok Heon;Ryu, Beyong-Hwan
    • Korean Journal of Materials Research
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    • v.25 no.12
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    • pp.719-726
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    • 2015
  • For a decade, solution-processed functional materials and various printing technologies have attracted increasingly the significant interest in realizing low-cost flexible electronics. In this study, Cu nanoparticles are synthesized via the chemical reduction of Cu ions under inert atmosphere. To prevent interparticle agglomeration and surface oxidation, oleic acid is incorporated as a surface capping molecule and hydrazine is used as a reducing agent. To endow water-compatibility, the surface of synthesized Cu nanoparticles is modified by a mixture of carboxyl-terminated anionic polyelectrolyte and polyoxylethylene oleylamine ether. For reducing the surface tension and the evaporation rate of aqueous Cu nanoparticle inks, the solvent composition of Cu nanoparticle ink is designed as DI water:2-methoxy ethanol:glycerol:ethylene glycol = 50:20:5:25 wt%. The effects of poly(styrene-co-maleic acid) as an adhesion promoter(AP) on rheology of aqueous Cu nanoparticle inks and adhesion of Cu pattern printed on polyimid films are investigated. The 40 wt% aqueous Cu nanoparticle inks with 0.5 wt% of Poly(styrene-co-maleic acid) show the "Newtonian flow" and has a low viscosity under $10mPa{\cdots}S$, which is applicable to inkjet printing. The Cu patterns with a linewidth of $50{\sim}60{\mu}m$ are successfully fabricated. With the addition of Poly(styrene-co-maleic acid), the adhesion of printed Cu patterns on polyimid films is superior to those of patterns prepared from Poly(styrene-co-maleic acid)-free inks. The resistivities of Cu films are measured to be $10{\sim}15{\mu}{\Omega}{\cdot}cm$ at annealing temperature of $300^{\circ}C$.

Comparison of the Performance of Thin Film Pressure Sensors with Polyimid and Silicon Oxide as a Insulating Layer (절연층으로 폴리이미드와 실리콘 산화막을 사용한 박막 압력 센서의 특성 비교)

  • Min, Nam-Ki;Lee, Seong-Rae;Chun, Jae-Hyung;Kim, Jeong-Wan
    • Proceedings of the KIEE Conference
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    • pp.296-298
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    • 1997
  • The performance of thin film pressure sensors with polyimide and silicon oxide as a insulating layer between the stainless steel diaphragm and the Cu-Ni strain gauges is presented. The polyimide was spun on the stainless steel diaphragm and cured in an oven. The silicon oxide was deposited by rf sputtering. The thin film pressure sensor with silicon oxide as a insulating layer showed a better nonlinearity and a lower hysteresis.

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Effects of Thermal Imidization and Annealing on Liquid Crystal Alignment ever Rubbed Polyimide Layers: Change in the Pretilt Angle

  • Paek, Sang-Hyon
    • Macromolecular Research
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    • v.9 no.6
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    • pp.303-312
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    • 2001
  • The fabrication of liquid crystal display (LCD) panels involves several thermal processes such as imidization of the alignment layer (AL) and annealing of the rubbed polyimide AL. The nature of these processes on the LC alignment, especially on the pretilt angle (Θ$\_$p/) has been systematically studied, employing various types of polyimide structures. The imidization effect depends on the nature of polyimid precursors; Θ$\^$p/ increases with the degree of the imidization for the main-chain type of ALs, due to the decrease in the surface polarity, but this relation is not applicable to the alkylated ones in which the steric effect at the AL surface by the aliphatic side chains is dominant. Annealing of the rubbed polyimide AL deteriorates its rubbing-induced molecular orientation and subsequently the overlying LC alignment, resulting in the decrease in Θ$\_$p/. Especially, annealing of the LC cell affects the LC-AL interaction as well as the AL orientation and thus its effect on LC alignment depends sensitively on the nature of LC-polyimide interface; aromatic moiety in the polyimide structure gives better thermal stability of LC alignment while fluorinated polyimide ALs induce the less stable alignment.

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Design and Fabrication of Flexible Thin Multilayered Planar Coil for Micro Electromagnetic Induction Energy Harvester (초소형 전자기 유도방식 에너지 하베스터용 연성 박막 다적층 평판 코일 설계 및 제작)

  • Park, Hyunchul
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.7
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    • pp.601-606
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    • 2016
  • In this paper, an energy harvester is developed that has advantages regarding piezoelectric noise minimization, mass production, and an easily available environmental energy source, electromagnetic induction, as well as low-frequency bandwidth and high amplitude. A process for fabricating a three-dimensional multilayered planar coil using micro-electro-mechanical systems (MEMS) on a flexible printed circuit board FPCB is introduced. Optimal shape and size were calculated via internal resistance and inductance, and a prototype was fabricated through the MEMS procedure while considering the possibility of mass production. Although the internal resistance matched the designed value, the electromotive force generated did not reach the intended amount. The main reason for the decrease in efficiency was the low area of coil outskirt exposed to the magnetic field while there was relative motion between the magnet and the coil.