• Title/Summary/Keyword: shielding films

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The Effect of Solvent and Doping Matter on the Electric Properties of Polyaniline Films (폴리아닐린 필름의 전기적 특성에 미치는 용매 및 도핑물질의 효과)

  • 김재욱
    • Electrical & Electronic Materials
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    • v.10 no.7
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    • pp.713-718
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    • 1997
  • Polyaniline free standing films cast from N-methyl-2-pyrrolidinone(NMP) solution, camphorsulfonic acid(HCSA), dodecylbenzensulfonic acid(HDBSA), inorganic matter(carbon black, graphite) and metal(silver) were prepared by processings. The properties of these films such as crystallinity, near-infrared absorption spectra and conductivity were investigated. The HCSA and HDBSA doped polyaniline films cast from m-cresol and chloroform solvents showed the metallic property and high crystallinity, respectively. The value of conductivity in the HCSA doped polyaniline film obtained 180 S/cm. We have obtained the value of conductivity 200 S/cm in the metal(silver) doped polyaniline film, which is higher than that of the HCSA doped polyaniline film. The metal(silver) doped polyaniline film shows good properties as a electromagnetic shielding material.

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Electromagnetic Shielding Characteristics of Polyaniline and Its Mixtures (폴리아닐린과 그 혼합물의 전자기파 차폐특성)

  • 박종수;임인호;최병수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.2
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    • pp.293-298
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    • 2001
  • EB-NMP free standing film is manufactured from NMP solution of polyaniline(emeraldine base EB). Also ES(emeraldine salt EB . HCl) film is manufactured by doping of EB-NMP film with 1 mole HCI aqueous solution. And EB-mixture films containing conductor(carbon black, graphite, Ag etc.) are prepared, In this study, electromagnetic interference shielding efficiency(EMI SE) of ES free standing film ($\sigma$=5 S/cm, t=0.14mm) is 23~25 dB in the frequency range of 10 MHz~1 GHz. ES-mixture(carbon black, graphite, Ag etc.) films, polyaniline film doped camphorsulfonic acid(CSA) show higher EMI SE(30~34 dB, 36~42 dB, 44~52 dB, 34~43 dB) property than that of ES free standing film, respectively.

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The Effects of Plasma Treatments on the Surface Energy of the Polycarbonates and on the Adhesion Strength of the Cu Film/Polycarbonate Interface (플라즈마 표면처리에 의한 폴리카보네이트의 표면에너지 및 구리박막과의 접착력 변화에 관한 연구)

  • Cho Byeong-Hoon;Lee Won-Jong;Park Young-Ho
    • Korean Journal of Materials Research
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    • v.15 no.11
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    • pp.745-750
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    • 2005
  • Polycarbonates are widely used as housing materials of electronic handsets. Since the polycarbonate is electrically insulating, there should be a conducting layer on the polycarbonate for EMI shielding. In this study, we sputter deposited Cu films on the polycarbonate substrates for EMI shielding. Plasma treatments of polycarbonates were used to increase the adhesion strength of the Cu film/polycarbonate interface. The surface energy of the polycarbonate was greatly increased from $30mJ/m^2 \;to\; 65mJ/m^2$ by a 200 W $O_2$ plasma treatment for 10s. It is thought that this is because of the ion bombardment. The adhesion strength of the sputter deposited Cu film to the polycarbonate was quantitatively measured by a 4 point bending tester. A moderate plasma surface treatment of the polycarbonate increased the Cu film/polycarbonate adhesion strength by $30\%$. The EMI shielding efficiency of the sputter deposited $10{\mu}m$ Cu lam on the polycarbonate showed 90dB in the range of 100MHz to 1000MHz.

High-functional Transparent Electrode Design and Shielding Effect (금속산화물 기반의 고성능 투명 전극 및 전자파 차단 효과)

  • Seongwon Cho;Wu-shin Cha;Junheon Ha;Junsik Lee;Jiwon Kang;Nguyen Thanh Tai;Joondong Kim
    • Current Photovoltaic Research
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    • v.11 no.1
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    • pp.13-17
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    • 2023
  • Functional transparent electrode was achieved by metal oxide-metal-Metal oxide (OMO) structure. Tailoring of metal oxide and metal layers, optically transparent and electrically excellent OMO films were investigated. Silver (Ag) is adopted for the metal layer and Ag oxide (AgO) is reactively formed by flowing O2 gas during the sputtering process. This spontaneous AgO formation from Ag simultaneously provides the good electrical interface with high transparency. Due to the feature of transparent electrode of OMO, it endows the shielding effect (SE) function of electromagnetic interference. Optically transparent and electrically conductive OMO electrode shows the high transmittance (83.7%) and low sheet resistance (6.5 Ω/☐) with SE of 29.54 dB.

Electromagnetic interference(EMI) shielding efficiency(SE) charhcteristics of IMI multilayer/PMMA structure for plasma display panel(PDP) filter.

  • Lee, Jung-Hyun;Sohn, Sang-Ho;Cho, Yong;Lee, Sang-Gul
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.872-876
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    • 2006
  • This study was made to examine the electromagnetic interference(EMI) shielding effect (SE) of multilayered thin films in which indium-tin oxide(ITO) and Ag were deposited alternately from 3layer to 9 layer on Poly Methyl Meth Acrylate(PMMA) substrate at room temperature using a PF sputtering. We measured optical and electrical characteristics by UV-spectrometer and 4 point probe. The measurement of EMI SE in frequency range from 50MHz to 1.5GHz was performed by using ASTM D4935-89 method. We compared the measured EMI SEs with theoretical simulation data. We obtained relatively low resistivity and high transmittance from the EMI SE multilayers. In this study, we obtain good optical electrical characteristics with a minimun transmittance of about 60% at 550nm wavelength and sheet resistance of $2{\sim}3ohm/sq$., respectivity. Measured EMI SEs were over 50dB and similar to theoretical simulation data.

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The Characterization of Electromagnetic Shielding of $SiO_2$/ITO Nano Films with Transition Metal Ions (전이금속이 첨가된 $SiO_2$/ITO 나노박막의 전자파 차폐특성)

  • 신용욱;김상우;손용배;윤기현
    • Journal of the Korean Ceramic Society
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    • v.38 no.1
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    • pp.15-21
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    • 2001
  • 전자파 차폐 및 반사방지용으로 사용되는 SiO$_2$/ITO 이층박막의 전기적 특성에 미치는 전이금속이온의 영향에 대해 고찰하고 전자파 차폐이론식으로부터 박막의 전도특성에 모사하여 효과적인 전자파 차폐효과를 얻기 위한 전도막을 설계하고자 하였다. ITO 상층부에 전이금속염을 첨가한 실리카 복합졸을 코팅하여 SiO$_2$/ITO 이층막을 제조한 결과 최저 표면저항치를 나타내는 첨가량은 전이금속의 종류에 따라 차이를 보이지만 Sn 및 Zn이 첨가된 졸로부터 형성된 박막은 $10^{5}$Ω/$\square$ 이하의 낮은 저항치를 보였으며 가장 안정된 표면저하을 나타내었다. 또한 전자파 차폐효과와 전도박막의 표면저항을 차폐이론식으로부터 모사한 결과 Zn과 Sn의 전이금속염이 첨가된 SiO$_2$/ITO 투명전도막은 TCO99에서 정한 전자파 차폐기준에 부합하였다.다.

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Characterization of Hexagonal Tungsten Bronze CsxWO3 Nanoparticles and Their Thin Films Prepared by Chemical Coprecipitation and Wet-Coating Methods

  • Kwak, Jun Young;Hwang, Tai Kyung;Jung, Young Hee;Park, Juyun;Kang, Yong-Cheol;Kim, Yeong Il
    • Journal of the Korean Chemical Society
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    • v.62 no.2
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    • pp.118-123
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    • 2018
  • The hexagonal tungsten bronze $Cs_xWO_3$ nanoparticle was synthesized by a chemical coprecipitation method of ammonium tungstate and $Cs_2CO_3$ in acidic condition. This synthetic method for cesium tungsten bronze is reported for the first time as far as we know. The synthesized $Cs_xWO_3$ as precipitated showed a weak crystallinity of hexagonal unit cell with a crystallite size of about 4 nm without annealing. When the synthesized $Cs_xWO_3$ was annealed in $N_2$ atmosphere, the crystallinity and crystallite size systematically increased maintaining the typical hexagonal tungsten bronze structure as the annealing temperature increased. The analyzed Cs content in the bronze was about 0.3 vs W, which is very close to the theoretical maximum value, 1/3 in cesium tungsten bronze. According to XPS analysis, the reduced tungsten ions existed as both the forms of $W^{5+}$ and $W^{4+}$ and the contents systematically increased as the annealing temperature increased up to $800^{\circ}C$. The $Cs_xWO_3$ thin films on PET substrate were also prepared by a wet-coating method using the ball-milled solution of the annealed $Cs_xWO_3$ nanoparticles at various temperatures. The near-infrared shielding property of these thin films increased systematically as the annealing temperature increased up to $800^{\circ}C$ as expected with the increased contents of reduced tungsten ions.

Preparation of conductive EPDM rubber sheets by electroless Ni-plating for electromagnetic interference shielding applications (무전해 Ni 도금법을 이용한 전자파 차폐용 도전성 EPDM 고무의 제조)

  • Lee, Byeong Woo;Cho, Soo Jin;Yang, Jun Seok
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.25 no.5
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    • pp.193-198
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    • 2015
  • In the study, electroless Ni-plating on flexible ethylene-propylene-diene-monomer (EPDM) rubber sheets for the application of an insert block for shielding electromagnetic interference of multi cable transit (MCT) systems was investigated. Ni crystallinity and adhesion have been found to vary with processing parameters such as pH and temperature of the plating bath. It was shown that Ni-films having the high crystallinity and optimum electric conductivity were obtained on EPDM rubber sheets under pH 7 and 8 at $60{\sim}70^{\circ}C$. The conductive Ni-plated EPDM rubber prepared at pH 7 at $70^{\circ}C$ showed the enhanced adhesion and electric conductivity, and the high electromagnetic interference shielding effect in the 400 MHz~1 GHz range.

Research Trends of Carbon Composite Film with Electromagnetic Interference Shielding and High Heat Dissipation (탄소 복합재 기반 전자파 차폐 및 고방열 일체형 필름 연구동향)

  • Park, Seong-Hyun;Kim, Myounghun;Kim, Kwang-Seok
    • Journal of the Microelectronics and Packaging Society
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    • v.28 no.4
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    • pp.1-10
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    • 2021
  • Recently, electronic components are becoming smaller and highly integrated. As a result, electromagnetic interference (EMI) and heat generation problems must be solved simultaneously with a small area and thickness. Graphene composites and graphite composites are lightweight materials that can simultaneously solve EMI shielding and heat dissipation problems with excellent electrical and thermal conductivity. With the recent development of synthetic technology and composite manufacturing technology, the research to application of their composites is increasing. In this paper, we reviewed the latest researches on composite films of graphene and graphite for EMI shielding and heat dissipation.