• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.299-304
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• 2020

Nanoparticles play an important role as a catalyst in many chemical syntheses. Colloidal nanoparticles were usually synthesized with reducing, capping, and shape directing agents which induce surface poisoning of catalysts. A new green synthesis for silver nanoparticles was developed by utilizing less additives which could be a hazardous waste. A crystallization technique was employed to reduce the amount of reducing and capping agents during synthesis resulting in less surface poisoning of the nanoparticle. The synthesized Ag nanoparticles using monosaccharides and disaccharides as reducing agents could be used as a catalyst for the redox reaction of resazurin and the mechanism of the reaction using Ag nanoparticles was studied.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.9-14
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• 2008

A Nano particle is a small particle with at least one dimension less than 100 nm Nanoparticle is currently used in an area cf intense scientific research, due to a wide variety cf potential applications in biomedical, optical, and electronic fields. In order to know the biological effect of the nine Nano particles on fertilized egg of Crassostrea gigas experiments were performed Development rates of control (free Nano particles) C. gigas to a particular larval stage (D-shape) was 78%. Development rate of C gigas to a parcicular larval stage (D-shape) after 24 hours exposure to 0.05ppm of AGZ020, Nano silver, P-25 and SnO were 22%, 52%, 58% and 76%, respectively. However, all fertilized eggs were destructed within 8 hours afters exposure to 20ppm of respective particles. On the other hand, All fertilized eggs were not affected after 24 hours respective exposure to 0.05ppm of In, Sb, Sn, Zn, and Ag-$TiO_2$ particles. However, development rates of C. gigas after 24 hours exposure to 20ppm of In, Sb, Sn, Zn, Ag-$TiO_2$ were 57%, 60%, 50%, 65%, and 64% respectively.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.347-351
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• 2014

We studied the green synthesis and antibacterial activity of chitosan-silver (Ag) nanocomposite films for application in food packaging. Green synthesis of Ag nanoparticles (AgNPs) was achieved by a chemical reaction involving a mixture of chitosan-silver nitrate ($AgNO_3$) in an autoclave at 0.1 MPa, $121^{\circ}C$, for 15-120 s. The formation of AgNPs in chitosan was confirmed by both UV-Visible spectrophotometry and transmission electron microscopy (TEM) and the effects of chitosan-$AgNO_3$ concentration and reaction time on the synthesis of AgNPs in chitosan were examined. The resulting chitosan-Ag composite films were characterized by various analytical techniques and their antibacterial activity was evaluated based on the formation of halo zones around films, indicating inhibition of the growth of Escherichia coli. A fourier-transform infrared (FTIR) spectroscopy analysis showed that free amino groups in chitosan acted as effective reductants and AgNP stabilizers. The composite films exhibited enhanced antibacterial activity with increasing Ag content on the surface of as-prepared composite films.

• Journal of IKEEE
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• v.20 no.2
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• pp.177-180
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• 2016

The effect of varying thickness of Ag/Ti metal bilayer and annealing time have investigated for controlling self-organized nanoparticles (NPs) on 4H-SiC substrate. In addition, Glass and Si substrate which have different surface energy from SiC were fabricated for analyzing interaction of agglomeration. The results of FE-SEM indicated the different formation behaviors of NPs in various ranges of fabrication condition. The surface energy was measured by using a Contact Angle Analyzer. The formation of network-like NPs was observed on Glass and 4H-SiC, respectively, whereas it was not the case on Si substrates. It has been found that the size of NPs increases with decreasing surface energy, due to particle size-dependent hydrophilic properties of substrates. The different formation behavior was explained by using Young's equation for the contact angles between the metal and different substrates.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.166-166
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• 2013

유체 플라즈마 공정은 금속 나노입자를 제조하는데 있어서 혁신적이고 친환경적인 공정 방법의 하나이다. 본 연구에서는 유체 플라즈마 공정을 통해 젤라틴 기지재 내에 은 나노입자를 합성하였고, 합성 된 용액은 동결건조를 통해 3D scaffold 형태의 생체복합체로 제조하였다. 이렇게 제조된 생체복합체의 물리적 특성 및 생물학적 특성 평가를 통해 생체복합체의 효율성과 항균 효과가 뛰어남을 확인하였다.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.120-126
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• 2018

As a basic study for environment-friendly production of bacterial cellulose (BC) dressing with antimicrobial activity, we isolated and identified acetic acid bacteria which are resistant to silver ions and can biosynthesize silver nanoparticles. Furthermore, conditions of BC production by selected strain were also investigated. Strain G7 isolated from decayed grape skin was able to grow in the presence of 0.1 mM $AgNO_3$ which was identified as Acetobacter intermedius based on 16S rRNA gene analysis. BC production was the highest in a medium containing 2% glucose as a carbon source, 2% yeast extract as a nitrogen source, and 0.115% acetic acid as a cosubstrate. Structural properties of BC produced in optimal medium were studied using Fourier-transform infrared spectroscopy and X-ray diffractometer, and it was found that BC produced was cellulose type I that was the same as a typical native cellulose. When strain G7 was cultured in an optimal medium containing 0.1 mM $AgNO_3$, the color of the culture broth turned into reddish brown, indicating that silver nanoparticles were formed. As a result of UV-Vis spectral analysis of the culture, it was found that a unique absorption spectrum of silver nanoparticles at 425 nm was also observed. Scanning electron microscopic observations showed that silver nanoparticles were formed on the surface and pores of BC membrane.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.640-640
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• 2013

본 연구에서는 유리 기판과 Si 기판에 Ag-doped ZnO 나노로드를 수열합성법을 이용하여 성장하였다. ZnO는 UV 영역에서 exciton 발광을 하며, 가시광선에서도 발광을 하는 것으로 알려져 있다. 그리고 Ag 금속은 입자형태로 ZnO 박막에 도포되었을 때 UV영역의 발광 세기를 강화시킨다는 사실이 알려져 있다. 이러한 내용을 바탕으로 ZnO 나노로드 합성 용액에 Ag powder의 양을 변화시켜 첨가하고, 유리와 Si기판을 넣고 80도에서 30분간 성장하였다. XRD, XPS를 통해 구조적 특성 변화를 보았고 SEM을 통해 나노로드의 형태를 확인하였다. 또한 PL, 투과도 측정을 통해 Ag 도핑에 따른 광학적 특성 변화를 확인하였다. SEM 측정으로 샘플의 단면을 확인한 결과 Ag 도핑 농도에 따른 차이가 거의 없음을 알았다. ZnO 나노로드가 성장된 유리 기판은 본래의 유리기판보다 투과도가 높았으며, Ag를 많이 첨가할수록 투과도가 낮아졌다.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.330-339
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• 2008

Effect of additives such as NP series nonionic surfactant and cosurfactant on AgCl nanoparticles was investigated where nanoparticles were prepared using two different types of water-in-oil (W/O) microemulsions containing silver nitrate and sodium chloride, respectively. Phase behavior experiments showed that the region of one phase W/O microemulsion was found to be broadened with an increase in the ethylene oxide length of a nonionic surfactant mainly due to an increase in hydrophilic nature of a surfactant. Photomicrographs obtained by transmission electron microscopy indicated that an increase in ethylene oxide length of a nonionic surfactant results in both increases in particle size and size distribution. Phase behavior experiments for the systems containing AOT surfactant, isooctane and aqueous solution of an inorganic salt showed that addition of a cosurfactant caused a shrinkage in phase region of one phase W/O microemulsion, especially water contents contained in W/O microemulsion with an increase in the chain length or the concentration of a cosurfactant used. Photomicrographs obtained by transmission electron microscopy indicated that characteristics of AgCl nanoparticles produced were dependent both on the radius of spontaneous curvature and film rigidity of a microemulsion.

• Membrane Journal
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• v.25 no.1
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• pp.1-6
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• 2015

It was known that the polarlized surface of silver nanoparticles could be interacted revesibly with olefin molecules for facilitated olefin transport. However, it was thought that it can be regenerated by interaction between oxide surface of AgNPs and olefin molecules because the surface of the silver nanoparticles is easily oxidized in the air. In order to investigate the effect of the silver oxide, 5 wt% AgO or $Ag_2O$ was dispersed in polymer PVP solutions and 0.005~0.02% electron acceptor as TCNQ or p-BQ were added to fabricate the separation membrane. After the addition of the electron acceptor, it was expected to improve the polarity on the surface of the silver oxide and the degree of dispersion. The characteristics of the separation membrane were identified by the gas permeance, XPS and TEM.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.795-801
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• 2012

Nanoparticles have received significant attention because of their unusual characteristics including high surface area to volume ratios. Thiol ligand have been used as stabilizers of metal nanoparticles since Brust et al. They reported the preparation method of ligand capped metal nanoparticles by protecting the nanoparticles with a self-assembled monolayer of dodecanethiolate. In this method, volatile organic compounds (VOCs) were used as sovents. This study was carried out to replace these VOCs with room temperature ionic liquids (RTILs). We used two type of ILs to prepare metal nanoparticles. One is a hydrophobic IL, [BMIM][[$PF_6$] (1-Butyl-3-methylimidazolium hexafluorophosphate) purchased from IL maker, C-Tri from Korea and the other one is a hydrophilic one, [BMIM][Cl] (1-Buthy-3-methylimdazolium chloride) sinthesized by us. In the case of preparing Ag and Au nanoparticles using [BMIM][Cl], we didn't use phase transition reagents and ethanol because it has hydrophilic property and preparing Au, Ag nanoparticles using [BMIM][[$PF_6$] the method is as same as Brust et al.'s except using [BMIM][[$PF_6$] instead of organic solvent because it has hydrophobic property. FT-IR and UV-vis, TEM, TGA analysis have been used in an attempt to determine the particle size and verify functional groups. The particle size obtained from TEM was very similar to those obtained by Brust et al. This is a clear example of ligand capped metal nanoparticles prepared using ionic liquids. And the experimental result demonstrated ionic liquids can act as a highly effective medium for the preparation and stabilization of gold and silver metal nanoparticles.