목적 : 본 연구는 항균 기능을 갖춘 안경테의 필요성에 주목하여 고분자 물질인 Polyvinylpyrrolidone(PVP)을 사용하여 은 나노 입자를 합성하고, 금속 안경테 소재에 코팅하여 항균성과 코팅 특성을 평가해 보고자 한다. 방법 : 안정성이 높은 고분자 물질인 PVP를 환원제, 분산제, 안정제로 사용하고 합성 온도를 달리하여 은 나노 입자를 합성하였다. 합성한 시료의 특성은 UV-visible spectrophotometer, SEM, EDS를 사용하여 분석하였으 며 paper disk diffusion method로 항균성을 평가하였다. 합성한 은 나노콜로이드를 금속 안경테 소재인 티타 늄, 스테인리스스틸 기판에 코팅하고 코팅막의 특성과 항균성을 측정하였다. 결과 : PVP를 사용하여 합성한 시료 모두에서 은(Ag)이 검출되어 은 나노 입자의 생성을 확인할 수 있었다. 합성 온도에 따른 은 나노 입자의 크기는 차이를 보였으며 Escherichia coli, Pseudomonas aeruginosa, Aspergillus brasiliensis의 경우 45℃에서 합성한 은 나노콜로이드의 항균활성이 가장 크게 나타났다. 이를 금속 안경테 소재 기판에 코팅한 후 항균성을 확인한 결과 코팅막의 항균력을 확인할 수 있었다. 결론 : PVP를 사용하여 합성한 은 나노콜로이드를 금속 안경테 소재 기판에 코팅한 결과 코팅막의 항균성이 확인되어 항균 기능을 가진 안경테 제작 시 항균 물질로 활용될 수 있을 것이라 사료된다.

본 연구에서는 방사성동위원소 추적자 실험을 통해서 산화아연 또는 두 종류의 은나노물질로 오염시킨 토양에서 지렁이 (Eisenia fetida)의 금속축적과 제거율을 비교하였고, 이들을 이온상의 Ag와 Zn으로 처리한 대조구와 비교하였다. 추가적으로 토양의 금속을 다단계추출법 (sequential extraction method)을 이용하여 금속의 결합 형태로부터 생물이용도 (bioavailability)를 예측하고 실제 생물축적 (BAF, bioaccumulation factor)과 비교하였다. ZnO 처리구의 BAF (0.06)는 아연이온 처리구 BAF (1.86)보다 31배 낮았는데, 이는 토양에서 ZnO의 생물전이가 매우 낮음을 제시해 준다. 한편, 은의 BAF는 금속의 오염 형태에에 무관 하게 0.11~0.17의 범위를 보였다. 다단계추출법을 통해서 아연이온 처리구의 아연은 토양에 비교적 약한 결합을 하 는 형태 (mobile fraction)에 35% 분포하여 아연이온처리구 값 (<20%)보다 높았고, 이는 전자의 더 높은 BAF와 일치 한다. 하지만, ZnO 처리구의 다단계추출은 생물이용도나 BAF를 잘 예측하지 못했으며 이는 ZnO가 토양에서 아연 이온과 지화학적으로 다른 거동을 하기 때문으로 추정된다. 지렁이 체내에 축적된 은의 제거율 (3.2~3.8% d-1)은 아연의 제거율 (1.2~1.7% d-1)보다 2~3배 더 높았다

물 여과, 단백질 정제 또는 생체 의학 여과 장치에 사용되는 분리막은 여러 가지 이유로 막 파울링을 거치게 된다. 박테리아에 의한 막 표면의 바이오필름 형성은 분리막의 내구성에 심각한 문제를 초래한다. 단백질 정제의 경우, 소수성 인 막의 표면으로 인해 막의 기공이 막히게 된다. 분리막의 파울링을 조절하는 방법에는 여러 가지가 있는데, 그 중 하나가 은나노 입자의 도입이다. 은나노 입자의 항균 특성은 잘 알려져 있고 따라서 여러 응용에 사용되고 있다. 본 총설에서는 은나 노 입자 또는 그 유도체가 박막 활성층에 도입되거나 또는 복합막 전체에 균일하게 분포된 분리막에 초점을 두었다.

This study investigates Ag coated Cu2O nanoparticles that are produced with a changing molar ratio of Ag and Cu2O. The results of XRD analysis reveal that each nanoparticle has a diffraction pattern peculiar to Ag and Cu2O determination, and SEM image analysis confirms that Ag is partially coated on the surface of Cu2O nanoparticles. The conductive paste with Ag coated Cu2O nanoparticles approaches the specific resistance of 6.4 Ω·cm for silver paste(SP) as (Ag) /(Cu2O) the molar ratio increases. The paste(containing 70 % content and average a 100 nm particle size for the silver nanoparticles) for commercial use for mounting with a fine line width of 100 μm or less has a surface resistance of 5 to 20 μΩ·cm, while in this research an Ag coated Cu2O paste has a larger surface resistance, which is disadvantageous. Its performance deteriorates as a material required for application of a fine line width electrode for a touch panel. A touch panel module that utilizes a nano imprinting technique of 10 μm or less is expected to be used as an electrode material for electric and electronic parts where large precision(mounting with fine line width) is not required.

이전 연구에서 올레핀/파라핀 분리를 위해 poly(ethylene oxide)(PEO)/Ag nanoparicles (AgNPs)(전구체AgBF4)/pbenzoquinone (p-BQ) 복합막이 제조되었으며, 이 복합체 분리막의 성능은 100시간까지 선택도 10과 투과도 15 GPU로 유지 되는 것이 확인되었다. 하지만 전구체인 AgBF4의 가격이 고가이기 때문에, 본 연구에서는 가격 측면에서 경쟁력이 있는 AgNO3를 Ag nanoparticles의 전구체로 사용하여 실험을 진행하였다. 그 결과 이미 존재하고 있는 NO3 -가 AgNPs를 감싸고 있기 때문에 분리 성능이 나오지 않는 것으로 관찰되었다. 이번 연구에서는 AgNO3를 Ag nanoparticles의 전구체로 사용하여도 높은 성능을 내기 위해 전자수용체 7,7,8,8-tetracyanoquinodimethane (TCNQ)를 사용하여 PEO, polyvinyl alcohol (PVA), polyether block amide-1657 (PEBAX-1657) 고분자 복합막을 제조한 결과, 고분자와 전자수용체의 영향과는 무관하게 분리 성능을 내지 못하는 것으로 분석되었으며, 이는 분리성능에 전구체의 음이온이 결정적 역할을 하는 것으로 분석되었다.

In this paper, the recovery and nanoparticle synthesis of Ag from low temperature co-fired ceramic (LTCC) by-products are studied. The effect of reaction behavior on Ag leaching conditions from the LTCC by-products is confirmed. The optimum leaching conditions are determined to be: 5 M HNO3, a reaction temperature of 75℃, and a pulp density of 50 g/L at 60 min. For the selective recovery of Ag, the [Cl]/[Ag] equivalence ratio experiment is performed using added HCl; most of the Ag (more than 99%) is recovered. The XRD and MP-AES results confirm that the powder is AgCl and that impurities are at less than 1%. Ag nanoparticles are synthesized using a chemical reduction process for recycling, NaBH4 and PVP are used as reducing agents and dispersion stabilizers. UV-vis and FE-SEM results show that AgCl powder is precipitated and that Ag nanoparticles are synthesized. Ag nanoparticles of 100% Ag are obtained under the chemical reaction conditions.

This study is aimed to separation propylene and propane using membrane process. Membrane-based gas separation enables a chemical process to be low-energy consuming, if high olefin selective membrane is developed. In this study, facilitated transport membrane (FTM) is used for propylene/ propane separation. We prepared FTM module using PVP/AgBF4/TCNQ composite membrane on top of hollow fiber membrane. We developed simulation program predicting the membrane separation properties under operation conditions. Separation properties of FTM module for propylene and propane were obtained from the simulation program based on the pure gas permeation data. Based on the these results, it is predicted that an one-stage membrane process provides 99.5% of propylene at permeate side from a binary gas mixture of 95 vol% C3H6/5 vol% C3H8 supplied as a feed gas.

There has been much interest in recycling electronic wastes in order to mitigate environmental problems and to recover the large amount of constituent metals. Silver recovery from electronic waste is extensively studied because of environmental and economic benefits and the use of silver in fabricating nanodevices. Hydrometallurgical processing is often used for silver recovery because it has the advantages of low cost and ease of control. Research on synthesis recovered silver into nanoparticles is needed for application to transistors and solar cells. In this study, silver is selectively recovered from the by-product of electrodes. Silver precursors are prepared using the dissolution characteristics of the leaching solution. In the liquid reduction process, silver nanoparticles are synthesized under various surfactant conditions and then analyzed. The purity of the recovered silver is 99.24%, and the average particle size of the silver nanoparticles is 68 nm.

Facilitated transport membranes in the solid state have been attractive because they can improve both the permeability and the selectivity simultaneously to overcome the trade-off behavior. The carrier activity for facilitated transport plays a key role in determining separation performance. We have reported the solid-state facilitated transport membranes containing surface-activated Ag nanoparticles (NPs) as an olefin carrier for separation of olefin/paraffin mixtures, particularly propylene/propane mixture. Interestingly, the surface positive charge density of Ag atom in Ag NPs was linearly correlated with the propylene solubility and also with the propylene/propane selectivity. In addition, the separation performance has been maintained unchanged up to 500 hours.

Noncontact direct-printed conductive silver patterns with an enhanced electrical resistivity are fabricated using a silver ink with a mixture of silver nanoparticles and nanoplates. The microstructure and electrical resistivity of the silver pattern are systematically investigated as a function of the mixing ratio of the nanoparticles and nanoplates. The pattern, which is fabricated using a mixture with a mixing ratio of 3(nanoparticles):7(nanoplates) and sintered at 200oC shows a highly dense and well-sintered microstructure and has a resistivity of 7.60 μΩ·cm. This originates a mutual synergistic effect through a combination of the sinterability of the nanoparticles and the packing ability of the nanoplates. This is a conductive material that can be used to fabricate noncontact direct-printed conductive patterns with excellent electrical conductivity for various flexible electronics applications, including solar cells, displays, RFIDs, and sensors.

Recent Engineered nanoparticles were increasingly exposed to environmental system with the wide application and production of nanomaterials, concerns are increasing about their environmental risk to soil and groundwater system. In order to assess the transport behavior of silver nanoparticles (AgNPs), a saturated packed column experiments were examined. Inductively coupled plasma-mass spectrometry and a DLS detector was used for concentration and size measurement of AgNPs. The column experiment results showed that solution chemistry had a considerable temporal deposition of AgNPs on the porous media of solid glass beads. In column experiment, comparable mobility improvement of AgNPs were observed by changing solution chemistry conditions from salts (in both NaCl and CaCl2 solutions) to DI conditions, but in much lower ionic strength (IS) with CaCl2. Additionally, the fitted parameters with two-site kinetic attachment model form the experimental breakthrough curves (BTCs) were associated that the retention rates of the AgNPs aggregates were enhanced with increasing IS under both NaCl and CaCl2 solutions.

Facilitated olefin transport membrane, containing positively charged silver nanoparticles (AgNPs) as olefin carriers dispersed in poly(vinyl pyrrolidone) (PVP), leads extremely high separation performances for propylene/propane mixtures. In this study, as representatives of electron withdrawing nitrobenzene compounds, 1,2-dinitrobenzene (DNB) and 3,4-dinitro toluene (DNT) were used for PVP/AgNPs membranes. The correlation between the surface charge density of AgNPs and the separation performance was investigated with X-ray photoelectron spectroscopy (XPS). A fairly good linear correlation between the surface charge density and the separation performance was confirmed, which meant that the positive charge density on the surface of AgNPs may be a key factor in determining the separation performance of facilitated olefin transport membranes.

고분자막이 가진 수투과능 한계와 비가역적 막오염에 의한 효율 저하는 막기반 수처리공정의 추가적인 경쟁력 확보를 위해 해결해야 하는 문제이다. 본 연구에서는 초고속 물투과 특성과 뛰어난 선택성을 지닌 Graphene oxide (GO)막 에 뛰어난 항균성을 가진 은나노(nAg)가 코팅된 막을 제작, 평가하였다. GO막 은 막오염 저감에 효과적일 수 있는 높은 친수성과 음표면전하와 같은 특성과 막오염에 취약할 수 있는 높은 비표면적과 뛰어난 흡착능력과 같은 특성을 동 시에 가진다. 따라서, 논란의 부분이 있는 GO막의 막오염에 대한 저항성의 확실한 향상을 위해 nAg를 적용하였다.

In this study, the properties of Ag-coated TiO2 nanoparticles were observed, while varying the molar ratio of water and Ag+ for the surfactant and TiO2. According to the XRD results, each nanoparticle showed a distinctive diffraction pattern. The intensity of the respective peaks and the sizes of the nanoparticles increased in the order of AT1(R1 = 5)(33.3 nm), AT2 (R1 = 10)(38.1 nm), AT3(R1 = 20)(45.7 nm), AT4(R1 = 40)(48.6 nm) as well as AT5(R2 = 0.2, R3 = 0.5)(41.4 nm), AT6(R2 = 0.3, R3 = 1)(45.1 nm), AT7(R2 = 0.5, R3 = 1.5)(49.3 nm), AT8(R2 = 0.7, R3 = 2)(57.2 nm), which values were consistent with the results of the UV-Vis. spectrum. The surface resistance of the conductive pastes fabricated using the prepared Ag-coated TiO2 nanoparticles exhibited a range 7.0~9.0(274~328 μΩ/cm2) times that of pure silver paste(ATP)(52 μΩ/cm2).

Soil column experiments were evaluated effects of silver nanoparticles (i.e., 0, 2.5, 5, and 10 mg/L) on the microbial viability which is strongly associated with the degradation of organic matter, pharmaceutically active compounds(PhACs) and biological oxidation of nitrogenous compounds during river bank filtration. The addition of silver nanoparticles resulted in almost no change in the aqueous matrix. However, the intact cell concentration decreased with addition of silver nanoparticles from 2.5 to 10 mg/L, which accounted for 76% to 82% reduction compared to that of control (silver nanoparticles free surface water). The decrease in adenosine triphosphate was more pronounced; thus, the number and active cells in aqueous phase were concurrently decreased with added silver nanoparticles. Based on the florescence excitation-emission matrix and liquid chromatograph - organic carbon detection analyses, it shows that the removal of protein-like substances was relatively higher than that of humic-like substances, and polysaccharide was substantially reduced. But the extent of those substances removed during soil passage was decreased with the increasing concentration of silver nanoparticles. The attenuation of ionic PhACs ranged from 55% to 80%, depending on the concentration of silver nanoparticles. The attenuation of neutral PhACs ranged between 72% and 77%, which was relatively lower than that observed for the ionic PhACs. The microbial viability was affected by silver nanoparticles, which also resulted in inhibition of nitrifiers.

In order to produce size-controllable Ag nanoparticles and a nanomesh-patterned Si substrate, we introduce a rapid thermal annealing(RTA) method and a metal assisted chemical etching(MCE) process. Ag nanoparticles were self-organized from a thin Ag film on a Si substrate through the RTA process. The mean diameter of the nanoparticles was modulated by changing the thickness of the Ag film. Furthermore, we controlled the surface energy of the Si substrate by changing the Ar or H2 ambient gas during the RTA process, and the modified surface energy was evaluated through water contact angle test. A smaller mean diameter of Ag nanoparticles was obtained under H2 gas at RTA, compared to that under Ar, from the same thickness of Ag thin film. This result was observed by SEM and summarized by statistical analysis. The mechanism of this result was determined by the surface energy change caused by the chemical reaction between the Si substrate and H2. The change of the surface energy affected on uniformity in the MCE process using Ag nanoparticles as catalyst. The nanoparticles formed under ambient Ar, having high surface energy, randomly moved in the lateral direction on the substrate even though the etching solution consisting of 10 % HF and 0.12 % H2O2 was cooled down to -20˚C to minimize thermal energy, which could act as the driving force of movement. On the other hand, the nanoparticles thermally treated under ambient H2 had low surface energy as the surface of the Si substrate reacted with H2. That's why the Ag nanoparticles could keep their pattern and vertically etch the Si substrate during MCE.

원자전달 라디칼 중합(ATRP)에 의해 poly(vinyl chloride) (PVC) 주사슬과 poly(styrene sulfonic acid) (PSSA) 곁사슬로 되어있는 양쪽성 PVC-g-PSSA 가지형 공중합체를 합성하였다. 합성된 고분자 전해질막을 10 wt% AgNO3 수용액에 담가 은이온으로 이온교환을 하였으며, 환원제를 통하여 은 나노입자를 성장시켰다. UV분광학과 XRD 분석을 통해 은 나노입자 성장을 확인하였다. 투과전자현미경(TEM) 분석결과 NaBH4를 사용하였을 때 10~20 nm 크기의 은 나노입자를 얻는데 가장 효과적임을 알 수 있었다. 또한 은 나노입자의 성장은 환원제의 농도와 환원 시간에 크게 영향을 받았다.

In this study, an enthalpy exchanger was coated by silver nano particles via spark discharge method and its antimicrobial and heat exchange efficiencies were evaluated. A method utilizing thermophoretic force was used to improve coating efficiency. Four spark discharge systems were parallel connected and generated silver nano aerosol particles (number concentration of 1.65×10⁸ particles/cc, mode diameter of 31 nm). The coating efficiency was evaluated according to various face velocities (V=0.25~1 m/s) and temperature gradients ((T_hot-T_cold)/T_hot=0~0.09). The maximum coating efficiency was 90.8 % when the face velocity was 0.25 m/s and the temperature gradient was 0.09 (Thot=30℃, Tcold=2℃). Silver nano particles were coated onto the enthalpy exchange element and two different coating amounts of silver nano particles (0.11 ㎍/cm³ , 0.22 ㎍/cm³ ) were tested. For evaluation of antimicrobial efficiency, the suspension test method with E. coli was used. After the suspension test method, CFU(colony forming unit)s of each test sample were counted and colony ratio was calculated. The colony ratio was decreased more quickly when the amount of coated silver particles was increased. When the contact time between each sample and suspension was over 3 hours, antimicrobial efficiencies of coated samples were more over 99.9 % for both amount of silver nano particle(0.11 ㎍/cm³ , 0.22 ㎍/cm³ ). The coating of silver nano particles did not affect the heat exchange efficiency.

Poly(vinyl chloride)-g-poly(styrene sulfonic acid) (PVC-g-PSSA) 가지형 공중합체를 합성한 후, 이를 이용하여 80℃에서 열적으로 환원하여 은 나노입자를 제조하였다. 반응 시간을 바꿈에 따라 다양한 구조의 은 나노입자를 제조하는데 성공하였다. 1시간 정도의 짧은 반응 시간에서는 가지형 공중합체의 미세 상분리 구조를 크게 변화시키지 않고 5 nm 크기의 작은 은 나노입자가 생성되었다. 5시간 정도의 중간 반응 시간에서는 30 내지 50 nm 정도의 크기를 갖는 은 나노입자가 생성되었다. 18시간 정도의 긴 반응 시간에서는, 은입자가 뭉친 허리케인 모양의 은 집합체가 관찰되었다.