• 공업화학
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• 제27권5호
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• pp.551-554
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• 2016

화학적 환원법에 이온성액체를 분산제로 사용하여 은 입자를 제조하였다. 이온성액체를 구성하는 양이온의 종류에 따라 제조된 은 입자는 다양한 구조를 가지는 것으로 관찰되었다. 이온성액체의 음이온에 상관없이 양이온의 알킬기의 길이가 길어질수록 은 입자가 작고 균일하게 형성되었다. 이는 이온성액체의 양이온이 길이에 따라 합성 중에 이온성액체들 간에 형성되는 구조체의 안정성에 차이를 보이기 때문이다. 조사된 7가지 이온성액체 중 [Omim][$PF_6$]가 은 입자 합성에 가장 효과적이었다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 1986년도 Priceedings Of The Third Korea-Japan Seminar On New Ceramics
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• pp.259-267
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• 1986

The sintering behavior of silver-oxide glass composite thick-film has been studied with varing glass content. It is shown that during heat treatment glass became liquid phase to deeply affect the microstructure development of the silver particles and to control the physical properties of the thick-films. As glass content increased, the initial repacking of silver particles took place rapidly but the homogeneities of the microstructure showed different features. When the glass content was over some range, the silver particles exuded glass to decrease net energy and glass formed liquid pools separated from the solid skeletons. Finally the relations between the microstructures and electrical properties of the thick-film were discussed.

• 한국분말재료학회지
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• 제24권6호
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• pp.464-471
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• 2017

A metal mesh TCE film is fabricated using a series of processes such as UV imprinting of a transparent trench pattern (with a width of $2-5{\mu}m$) onto a PET film, filling it with silver paste, wiping of the surface, and heat-curing the silver paste. In this work nanosized (40-50 nm) silver particles are synthesized and mixed with submicron (250-300 nm)-sized silver particles to prepare silver paste for the fabrication of metal mesh-type TCE films. The filling of these silver pastes into the patterned trench layer is examined using a specially designed filling machine and the rheological testing of the silver pastes. The wiping of the trench layer surface to remove any residual silver paste or particles is tested with various mixture solvents, and ethyl cellosolve acetate (ECA):DI water = 90:10 wt% is found to give the best result. The silver paste with 40-50 nm Ag:250-300 nm Ag in a 10:90 wt% mixture gives the highest electrical conductance. The metal mesh TCE film obtained with this silver paste in an optimized process exhibits a light transmittance of 90.4% and haze at 1.2%, which is suitable for TSP application.

• 한국재료학회지
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• 제18권5호
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• pp.283-288
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• 2008

The effect of sintering aids and glass-frit on the densification and resistivity of silver paste was investigated in an effort to enhance the sintered density and electrical conductivity of the silver electrode. To prepare Pb-free silver paste for use at low sintering temperatures, two commercial silver powders ($0.8\;{\mu}m$ and $1.6\;{\mu}m$ in size) and 5wt.% lab-synthesized nanoparticles (30-50 nm in size) as a sintering aids were mixed with 3 wt.% or 6 wt.% of glass frit ($Bi_2O_3$-based) using a solvent and three roll mills. Thick films from the silver paste were prepared by means of screen printing on an alumina substrate followed by sintering at $450^{\circ}C$ to $550^{\circ}C$ for 15 min. Silver thick films from the paste with bimodal particles showed a high packing density, high densification during sintering and low resistivity compared to films created using monomodal particles. Silver nanoparticles as a sintering aid enhanced the densification of commercial silver powder at a low sintering temperature and induced low resistivity in the silver thick film. The glass frit also enhanced the densification of the films through liquid phase sintering; however, the optimum content of glass frit is necessary to ensure that a dense microstructure and low resistivity are obtained, as excessive glass-frit can provoke low conductivity due to the interconnection of the glass phase with the high resistivity between the silver particles.

• 폴리머
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• 제31권6호
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• pp.543-549
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• 2007

폴리우레탄의 우수한 기계적 물성에 전기 전도성을 가질 수 있도록 은 입자와의 복합체를 제조하였다. 균일하고 우수한 물성을 나타내기 위해서는 고른 분산성이 중요하게 되는데 폴리우레탄의 hard segment와 soft segment를 바꿔가며 가장 열적 안정성이 뛰어나고 은 입자를 균일하게 분산시킬 수 있는 폴리우레탄의 구조를 파악하였다. 열적 안정성은 방향족 증가와 사슬의 hard segment 비율 증가에 따라 높아짐을 알 수 있었고 분산성에서는 hard segment의 방향족이 포함된 것이 지방족보다 우수한 분산성을 가졌다. 또한 soft segment에 따라서는 낮은 분자량에서 사슬의 motility로 인해 좋은 분산성을 나타내었다. 하지만 전기 전도성에서는 고른 분산성보다도 입자간의 inter-connection을 이룰 수 있는 형태가 가장 낮은 저항값을 나타내었으며. NDI와 낮은 분자량의 PEG로 이루처진 복합체가 가장 좋은 물성을 나타내었다.

• 자원리싸이클링
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• 제15권4호
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• pp.19-26
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• 2006

함은 폐재의 리싸이클링을 위한 연구의 일환으로써 Hydrazine Hydrate을 환원제로 사용하여 질산은 수용액으로부터 Ag 나노분말을 제조하기 위한 실험을 수행하였다. 이를 위해 질산은을 소정 농도로 증류수에 용해시킨 수용액에 Ag 미립자의 응집방지를 위한 분산제로써 Tamol NN8906 혹은 Tween 20을 미리 혼합한 다음 환원제인 Hydrazine Hydrate 용액을 첨가하는 방법으로 환원반응을 실시하였다. 환원반응을 통하여 제조한 Ag 미립자는 입도분석기 및 TEM 측정을 통하여 형상과 평균입도를 측정하였다. Hydrazine Hydrate에 의한 은의 환원을 위해서는 이론치의 약 2배를 첨가해 주어야 하는 것으로 나타났으며, Tamol NN8906을 분산제로 사용하여 제조한 Ag 나노분발은 매우 좁은 입도범위의 분포특성을 보여 주었다. Tween 20을 분산제로 사용한 경우의 입도 분포는 bimodal 혹은 multimodal distribution을 보였으며, 입자 모양에 있어서는 Tamol NN8906과 Tween 20이 모두 비슷하게 표면이 매끄러운 불규칙한 모양의 입자들로 구성되어 있었다.

• Journal of Applied Biological Chemistry
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• 제58권2호
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• pp.113-116
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• 2015

Silver materials may be toxic in humans because they can enter the body and accumulate, typically in the lungs. We hypothesized that the cytotoxicity of naive silver materials is affected by their size and shape. Our in vitro assays revealed that the overall toxicity was in the following order: submicro-particles>wires>micro-particles. These results contrast with previous studies, which showed that silver wires are the most toxic among the three tested materials, possibly due to differences in cell lines. Evaluations of in vivo pulmonary toxicity revealed eryptosis in the cavity lining of the lung sections. The observed eryptosis was consistent with the in vitro results. Our results indicate that silver materialinduced cytotoxicity must be measured and compared using various methods.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3707-3711
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• 2011

Silver nanoparticles coated with silica can be obtained by the reduction of $AgNO_3$ with hydrazine in the presence of NaOH-stabilized, active silicic acid (polysilicic acid). The size of the silver nanoparticles and the silica shell thicknesses were affected by varying the hydrazine content, the active silicic acid content and the experimental method (e.g. hydrothermal method). Typically, silver nanoparticles sized around 40 nm were aggregated, connected by silica. The presence of peaks centered around 400 nm in UV-vis spectra corresponds to the surface plasmon resonance of silver nanoparticles. The size of the aggregated silver nanoparticles increased with increasing hydrazine concentration. Under hydrothermal conditions at $150^{\circ}C$ the formation of individual silica particles was observed and the sizes of the silver nanoparticles were reduced. The hydrothermal treatment of silver nanoparticles at $180^{\circ}C$ gives a well-defined Ag@$SiO_2$ core-shell in aggregated silica sol particles. The absorption band observed at around 412 nm were red-shifted with respect to the uncoated silver nanoparticles (${\lambda}_{max}$ = 399 nm) due to the larger refractive index of silica compared to that of water. The formation of silver nanoparticles coated with silica is confirmed by UV-visible absorption spectra, transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS) data.

• 공업화학
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• 제33권6호
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• pp.574-580
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• 2022

Dendrite 형태의 구리 입자 표면을 은으로 무전해 도금을 하는 과정에서, 치환도금(displacement plating)과 화학 환원도금(reducing electroless plating)을 병용하여 다양한 silver-coated copper (Ag@Cu) 입자들을 제조하였다. Ag@Cu 입자들의 물리화학적 특성은 SEM-EDS, TGA, XPS, XRD 및 BET 등으로 분석하였으며, 환원반응에 의하여 코팅되는 은은 구리 입자 표면에 나노 입자 형태로 형성되는 것을 확인할 수 있었다. Ag@Cu 입자들을 에폭시 수지와 복합화하여 도전성 필름을 제조하고 그의 열적 안정성을 평가하였다. 치환 반응과 환원 반응의 차이가 Ag@Cu 필름의 초기 저항 및 열적 안정성에 미치는 영향에 관하여 연구하였다.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4221-4226
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• 2011

Honeycomb-patterned polyvinypyrrolidone (PVP) thin films coated with nanometer-sized silver particles were prepared using honeycomb-patterned polystyrene (PS) template films fabricated by casting a polystyrene solution under humid condition. Silver was first metallized on the patterned PS films via silver nitrate ($AgNO_3$) reduction using tetrathiafulvalene (TTF) and a small amount of PVP as the reductant and dispersing agent, respectively. The effects of $AgNO_3$, TTF, and PVP solution concentrations during the reduction process in acetonitrile were determined to obtain a uniform silver-coated honeycomb-patterned PS film. Second, the silver-metallized patterned porous PS films were filled with high PVP concentration solutions via the spincoating process. Silver-coated patterned PVP films were obtained by peeling off the PVP layer from the template PS film after drying. The results show that the honeycomb-patterned PVP films uniformly coated with silver particles are conveniently obtained using the silver-coated patterned PS template, although the direct fabrication of these films using water droplets under humid conditions was not feasible because of the water solubility of PVP.